pain

More about Pain: Causes and symptoms Diagnosis Treatment Alternative treatment Prognosis Prevention Resources

Definition

Pain is an unpleasant feeling that is conveyed to the brain by sensory neurons. The discomfort signals actual or potential injury to the body. However, pain is more than a sensation, or the physical awareness of pain; it also includes perception, the subjective interpretation of the discomfort. Perception gives information on the pain's location, intensity, and something about its nature. The various conscious and unconscious responses to both sensation and perception, including the emotional response, add further definition to the overall concept of pain.

Description

Pain arises from any number of situations. Injury is a major cause, but pain may also arise from an illness. It may accompany a psychological condition, such as depression, or may even occur in the absence of a recognizable trigger.

Acute pain

Acute pain often results from tissue damage, such as a skin burn or broken bone. Acute pain can also be associated with headaches or muscle cramps. This type of pain usually goes away as the injury heals or the cause of the pain (stimulus) is removed.

To understand acute pain, it is necessary to understand the nerves that support it. Nerve cells, or neurons, perform many functions in the body. Although their general purpose, providing an interface between the brain and the body, remains constant, their capabilities vary widely. Certain types of neurons are capable of transmitting a pain signal to the brain.

As a group, these pain-sensing neurons are called nociceptors, and virtually every surface and organ of the body is wired with them. The central part of these cells is located in the spine, and they send threadlike projections to every part of the body. Nociceptors are classified according to the stimulus that prompts them to transmit a pain signal. Thermoreceptive nociceptors are stimulated by temperatures that are potentially tissue damaging. Mechanoreceptive nociceptors respond to a pressure stimulus that may cause injury. Polymodal nociceptors are the most sensitive and can respond to temperature and pressure. Polymodal nociceptors also respond to chemicals released by the cells in the area from which the pain originates.

Nerve cell endings, or receptors, are at the front end of pain sensation. A stimulus at this part of the nociceptor unleashes a cascade of neurotransmitters (chemicals that transmit information within the nervous system) in the spine. Each neurotransmitter has a purpose. For example, substance P relays the pain message to nerves leading to the spinal cord and brain. These neurotransmitters may also stimulate nerves leading back to the site of the injury. This response prompts cells in the injured area to release chemicals that not only trigger an immune response, but also influence the intensity and duration of the pain.

Chronic and abnormal pain

Chronic pain refers to pain that persists after an injury heals, cancer pain, pain related to a persistent or degenerative disease, and long-term pain from an unidentifiable cause. It is estimated that one in three people in the United States will experience chronic pain at some point in their lives. Of these people, approximately 50 million are either partially or completely disabled.

Chronic pain may be caused by the body's response to acute pain. In the presence of continued stimulation of nociceptors, changes occur within the nervous system. Changes at the molecular level are dramatic and may include alterations in genetic transcription of neurotransmitters and receptors. These changes may also occur in the absence of an identifiable cause; one of the frustrating aspects of chronic pain is that the stimulus may be unknown. For example, the stimulus cannot be identified in as many as 85% of individuals suffering lower back pain.

Other types of abnormal pain include allodynia, hyperalgesia, and phantom limb pain. These types of pain often arise from some damage to the nervous system (neuropathic). Allodynia refers to a feeling of pain in response to a normally harmless stimulus. For example, some individuals who have suffered nerve damage as a result of viral infection experience unbearable pain from just the light weight of their clothing. Hyperalgesia is somewhat related to allodynia in that the response to a painful stimulus is extreme. In this case, a mild pain stimulus, such as a pin prick, causes a maximum pain response. Phantom limb pain occurs after a limb is amputated; although an individual may be missing the limb, the nervous system continues to perceive pain originating from the area.

— Julia Barrett

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n.

1. An unpleasant sensation occurring in varying degrees of severity as a consequence of injury, disease, or emotional disorder.
2. Suffering or distress.
3. pains The pangs of childbirth.
4. pains Great care or effort: take pains with one's work.
5. Informal. A source of annoyance; a nuisance.

v., pained, pain·ing, pains.

v.tr.
To cause pain to; hurt or injure.

v.intr.
To be the cause of pain.

idiom:

on (or under) pain of

1. Subject to the penalty of (a specified punishment, such as death).

[Middle English, from Old French peine, from Latin poena, penalty, pain, from Greek poinē, penalty.]

SYNONYMS   pain, ache, pang, smart, stitch, throe, twinge. These nouns denote a sensation of severe physical discomfort: abdominal pain; aches in my leg; the pangs of a cramped muscle; aspirin that alleviated the smart; a stitch in my side; the throes of dying; a twinge of arthritis.

For more information on pain, visit Britannica.com.

Definition and classification

Pain is a universal human experience. The International Association for the Study of Pain (IASP) defines pain as "an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage." Pain may be a symptom of an underlying disease or disorder, or a disorder in its own right.

At the same time that pain is a universal experience, however, it is also a complex one. While the physical sensations involved in pain may be constant throughout history, the ways in which humans express and treat pain are shaped by their respective cultures and societies. Since the 1980s, research in the neurobiology of pain has been accompanied by studies of the psychological and sociocultural factors that influence people's experience of pain, their use of health care systems, and their compliance with various treatments for pain. As of 2003, the World Health Organization (WHO) emphasizes the importance of an interdisciplinary approach to pain treatment that takes this complexity into account.

Types of pain

Pain can be classified as either acute or chronic. Acute pain is a direct biological response to disease, inflammation, or tissue damage, and usually lasts less than one month. It may be either continuous or recurrent (e.g., sickle cell disease). Acute pain serves the long-term wellbeing of humans and the higher animals by alerting them to an injury or condition that needs treatment. In humans, acute pain is often accompanied by anxiety and emotional distress; however, its cause can usually be successfully diagnosed and treated. Some researchers use the term "eudynia" to refer to acute pain.

In contrast, chronic pain has no useful biological function. It can be defined broadly as pain that lasts longer than a month following the healing of a tissue injury; pain that recurs or persists over a period of three months or longer; or pain related to a tissue injury that is expected to continue or get worse. Chronic pain may be either continuous or intermittent; in either case, however, it frequently leads to weight loss, sleep disturbances, fatigue, and other symptoms of depression. According to an article in the New York Times, chronic pain is the most common under-lying cause of suicide. Unlike acute pain, chronic pain is resistant to most medical treatments. It is sometimes called "maldynia," and is considered a disorder in its own right.

Pain that is caused by organic diseases and disorders is known as somatogenic pain. Somatogenic pain in turn can be subdivided into nociceptive pain and neuropathic pain. Nociceptive pain occurs when pain-sensitive nerve endings called nociceptors are activated or stimulated. Most nociceptors in the human body are located in the skin, joints and muscles, and the walls of internal organs. There may be as many as 1,300 nociceptors in a square inch (6.4 square centimeter) of skin. However, there are fewer nociceptors in muscle tissue and the internal organs, as they are covered and protected by the skin. Nociceptors are specialized to detect different types of painful stimuli—some are sensitive to heat or cold, while others detect pressure, toxic substances, sharp blows, or inflammation caused by infection or overuse.

In contrast to nociceptive pain, neuropathic pain results from damage to or malfunctioning of the nervous system itself. It may involve the central nervous system (the brain and spinal cord); the peripheral nervous system (the nerve trunks leading away from the spine to the limbs, plus the 12 pairs of cranial nerves on the lower surface of the brain); or both. Neuropathic pain is usually associated with an identifiable disorder such as stroke, diabetes, or spinal cord injury, and is frequently described as having a "hot" or burning quality.

Psychogenic pain is distinguished from somatogenic pain by the influence of psychological factors on the intensity of the patient's pain or degree of disability. The patient is genuinely experiencing pain—that is, he or she is not malingering—but the pain has either no organic explanation or else a weak one. Common psychogenic pain syndromes include chronic headache or low back pain; atypical facial pain; or pelvic pain of unknown origin.

Some cases of psychogenic pain belong to a group of mental disorders known as somatoform disorders. According to the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), somatoform disorders are defined by "the presence of physical symptoms that suggest a general medical condition," but cannot be fully explained by such a condition, by the direct effects of a drug or other substance, or by another mental disorder. The somatoform disorders include somatization disorder, characterized by chronic complaints of unexplained physical symptoms, often involving multiple sites in the body; hypochondriasis is a preoccupation with illness that persists in spite of the doctor's reassurance; and pain disorder, characterized by physical pain that is intensified by psychological factors, often becoming the focus of the patient's life and impairing his or her family relationships and ability to work.

It is important to recognize that some pain syndromes may involve more than one type of pain. For example, a cancer patient may suffer from neuropathic pain as a side effect of cancer treatment as well as nociceptive pain associated with pressure from the tumor itself on nociceptors in a blood vessel or hollow organ. In addition to the somatogenic pain, the patient may experience psychogenic pain related to the loss of physical functioning or attractiveness, coupled with anxiety about the progression or recurrence of the cancer. Other pain syndromes do not fit neatly into either somatogenic or psychogenic categories. A case in point would be certain types of chronic headache that involve the stimulation of nociceptors in the tissues of the head and neck as well as psychogenic factors related to the patient's handling of stress.

Description

How the body feels pain

A person begins to feel pain when nociceptors in the skin, muscles, or internal organs detect pressure, inflammation, a toxic substance, or another harmful stimulus. The pain message travels along peripheral nerve fibers in the form of electrical impulses until it reaches the spinal cord. At this point, the pain message is filtered by specialized nerve cells that act as gatekeepers. Depending on the cause and severity of the pain, the nerve cells in the spinal cord may either activate motor nerves, which govern the ability to move away from the painful stimulus; block out the painful message; or release chemicals that increase or lower the strength of the original pain message on its way to the brain. The part of the spinal cord that receives and "processes" the pain messages from the peripheral nerves is known as the dorsal horn.

After the pain message reaches the brain, it is relayed to an egg-shaped central structure called the thalamus, which transmits the information to three specialized areas within the brain: the somatosensory cortex, which interprets physical sensations; the limbic system, which forms a border around the brain stem and governs emotional responses to physical stimuli; and the frontal cortex, which handles thinking. The activation of these three regions explains why human perception of pain is a complex combination of sensation, emotional arousal, and conscious thought.

In addition to receiving and interpreting pain signals, the brain responds to pain by activating parts of the nervous system that send additional blood to the injured part of the body or that release natural pain-relieving chemicals, including serotonin, endorphins, and enkephalins.

Factors that affect pain perception

LOCATION AND SEVERITY OF PAIN Pain varies in intensity and quality. It may be mild, moderate, or severe. In terms of quality, it may vary from a dull ache to sharp, piercing, burning, pulsating, tingling, or throbbing sensations; for example, the pain from jabbing one's finger on a needle feels different from the pain of touching a hot iron, even though both injuries involve the same part of the body. If the pain is severe, the nerve cells in the dorsal horn transmit the pain message rapidly; if the pain is relatively mild, the pain signals are transmitted along a different set of nerve fibers at a slower rate.

The location of the pain often affects a person's emotional and cognitive response, in that pain related to the head or other vital organs is usually more disturbing than pain of equal severity in a toe or finger.

GENDER Recent research has shown that sex hormones in mammals affect the level of tolerance for pain. The male sex hormone, testosterone, appears to raise the pain threshold in experimental animals, while the female hormone, estrogen, appears to increase the animal's recognition of pain. Humans, however, are influenced by their personal histories and cultures as well as by body chemistry. Studies of adult volunteers indicate that women tend to recover from pain more quickly than men, cope more effectively with it, and are less likely to allow pain to control their lives. One explanation of this difference comes from research with a group of analgesics known as kappa-opioids, which work better in women than in men. Some researchers think that female sex hormones may increase the effectiveness of some analgesic medications, while male sex hormones may make them less effective. In addition, women appear to be less sensitive to pain when their estrogen and progesterone levels are high, as happens during pregnancy and certain phases of the menstrual cycle. It has been noted, for example, that women with irritable bowel syndrome (IBS) often experience greater pain from the disorder during their periods.

FAMILY Another factor that influences pain perception in humans is family upbringing. Some parents comfort children who are hurting, while others ignore or even punish them for crying or expressing pain. Some families allow female members to express pain but expect males to "keep a stiff upper lip." People who suffer from chronic pain as adults may be helped by recalling their family's spoken and unspoken "messages" about pain, and working to consciously change those messages.

CULTURE AND ETHNICITY In addition to the nuclear family, a person's cultural or ethnic background can shape his or her perception of pain. People who have been exposed through their education to Western explanations of and treatments for pain may seek mainstream medical treatment more readily than those who have been taught to regard hospitals as places to die. On the other hand, Western medicine has been slower than Eastern and Native American systems of healing to recognize the importance of emotions and spirituality in treating pain. The recent upsurge of interest in alternative medicine in the United States is one reflection of dissatisfaction with a one-dimensional "scientific" approach to pain.

There are also differences among various ethnic groups within Western societies regarding ways of coping with pain. One study of African American, Irish, Italian, Jewish, and Puerto Rican patients being treated for chronic facial pain found differences among the groups in the intensity of emotional reactions to the pain and the extent to which the pain was allowed to interfere with daily functioning. However, much more work on larger patient samples is needed to understand the many ways in which culture and society affect people's perception of and responses to pain.

Demographics

Acute pain, particularly in its milder forms, is a commonplace experience in the general population; most people can think of at least one occasion in the past week or month when they had a brief tension headache, felt a little muscle soreness, cut themselves while shaving, or had a similar minor injury. On the other hand, chronic pain is more widespread than is generally thought; the American Chronic Pain Association estimates that 86 million people in the United States suffer from and are partially disabled by chronic pain. Two Canadian researchers evaluating a set of 13 studies of chronic pain done in North America, Europe, and Australia reported that the prevalence of severe chronic pain in these parts of the world is about 8% in children and 11% in adults. In terms of the economic impact of chronic pain, various productivity audits of the American workforce have stated that such pain syndromes as arthritis, lower back pain, and headache cost the United States between $80 and $90 billion every year.

The demographics of chronic pain depend on the specific disorder, including:

• Chronic pelvic pain (CPP) is more common in women than in men; it is thought to affect about 14% of adult women worldwide. In the United States, CPP is most common among women of reproductive age, particularly those between the ages of 26 and 30. It appears to be more common among African Americans than among Caucasians or Asian Americans. In addition, a history of sexual abuse before age 15 is a risk factor for CPP in adult life.
• Lower back pain (LBP) is the most common chronic disability in persons younger than 45. One researcher estimates that 80% of people in the United States will experience an episode of LBP at some point in life. About 3–4% of adults are disabled temporarily each year by LBP, with another 1% of the working-age population disabled completely and permanently. While 95% of patients with LBP recover within six to 12 weeks, the back pain becomes a chronic syndrome in the remaining 5%.
• Headaches in general are very common in the adult population in North America; about 95% of women and 90% of men in the United States and Canada have had at least one headache in the past twelve months. Most of these are tension headaches. Migraine headaches are less common than tension headaches, affecting about 11% of the population in the United States and 15% in Canada. Migraines occur most frequently in adults between the ages of 25 and 55; the gender ratio is about 3 F:1 M. Cluster headaches are the least common type of chronic headaches, affecting about 0.4% of adult males in the United States and 0.08% of adult females. The gender ratio is 7.5–5 M:1 F.
• Atypical facial pain is a less-common chronic pain syndrome, affecting one or two persons per 100,000 population each year. It is almost entirely a disorder of adults. Atypical facial pain is thought to affect men and women equally, and to occur with equal frequency in all races and ethnic groups.

Evaluation of pain

Patient description and history

A doctor's first step in evaluating a patient's pain is obtaining a detailed description of the pain, including:

• severity
• timing (time of day; continuous or intermittent)
• location in the body
• quality (piercing, burning, aching, etc.)
• factors that relieve the pain or make it worse (temperature or humidity; body position or level of activity; foods or medications; emotional stress, etc.)
• its relationship to mood swings, anxiety, or depression

The doctor will then take the patient's medical history, including past illnesses, injuries, and operations as well as a family history. In some cases, the doctor may need to ask about experiences of emotional, physical, or sexual abuse. The doctor will also make a list of all the medications that the patient takes on a regular basis. Other information that may help the doctor evaluate the pain includes the patient's occupation and level of functioning at work; marriage and family relationships; social contacts and hobbies; and whether the patient is involved in a lawsuit for injury or seeking workers' compensation. This information may be helpful in understanding what the patient means by "pain" as well as what may have caused the pain, particularly because many people find it easier to discuss physical pain than anxiety, anger, depression, or sexual problems.

Some doctors may give the patient a brief written pain questionnaire to fill out in the office. There are a number of different instruments of this type, some of which are designed to measure pain associated with cancer, arthritis, HIV infection, or other specific diseases. Most of these rating questionnaires ask the patient to mark their pain level on a scale from zero to 10 or zero to 100 with zero representing "no pain" and the higher number representing "worst pain imaginable" or "unbearable pain." The patient then answers a few multiple-choice questions regarding the impact of the pain on his or her employment, relationships, and overall quality of life.

Physical examination

A thorough physical examination is essential in identifying the specific disorders or injuries that are causing the pain. The most important part of pain management is removing the underlying cause(s) whenever possible, even when there is a psychological component to the pain.

Special tests

Although there are no laboratory tests or imaging studies that can demonstrate the existence of pain as such or measure its intensity directly, the doctor may order special tests to help determine the cause(s) of the pain. These studies may include one or more of the following:

• Imaging studies, usually x rays or magnetic resonance imagings (MRIs). These studies can detect abnormalities in the structure of bones or joints, and differentiate between healthy and diseased tissues.
• Neurological tests. These tests evaluate the patient's movement, gait, reflexes, coordination, balance, and sensory perception.
• Electrodiagnostic tests. These tests include electromyography (EMG), nerve conduction studies, and evoked potential (EP) tests. In EMG, the doctor inserts thin needles in specific muscles and observes the electrical signals that are displayed on a screen. This test helps to pinpoint which muscles and nerves are affected by pain. Nerve conduction studies are done to determine whether specific nerves have been damaged. The doctor positions two sets of electrodes on the patient's skin over the muscles in the affected area. One set of electrodes stimulates the nerves supplying that muscle by delivering a mild electrical shock; the other set records the nerve's electrical signals on a machine. EP tests measure the speed of transmission of nerve impulses to the brain by using two electrodes, one attached to the patient's arm or leg and the other to the scalp.
• Thermography. This is an imaging technique that uses infrared scanning devices to convert changes in skin temperature into electrical impulses that can be displayed as different colors on a computer monitor. Pain related to inflammation, nerve damage, or abnormalities in skin blood flow can be effectively evaluated by thermography.
• Psychological tests. Such instruments as the Minnesota Multiphasic Personality Inventory (MMPI) may be helpful in assessing hypochondriasis and other personality traits related to psychogenic pain.

Treatment

Treatment of either acute or chronic pain may involve several different approaches to therapy.

Medications

Medications to relieve pain are known as analgesics. Aspirin and other nonsteroidal anti-inflammatory drugs, or NSAIDs, are commonly used analgesics. NSAIDs include such medications as ibuprofen (Motrin, Advil), ketoprofen (Orudis), diclofenac (Voltaren, Cataflam), naproxen (Aleve, Naprosyn), and nabumetone (Relafen). These medications are effective in treating mild or moderate pain. A newer group of NSAIDs, which are sometimes called "superaspirins" because they can be given in higher doses than aspirin without causing stomach upset or bleeding, are known as COX-2 inhibitors. The COX-2 inhibitors include celecoxib (Celebrex), rofecoxib (Vioxx), and valdecoxib (Bextra).

For more severe pain, the doctor may prescribe an NSAID combined with an opioid, usually codeine or hydrocodone. Opioids, which are also called narcotics, are strong painkillers derived either from the opium poppy Papaver somniferum or from synthetic compounds that have similar effects. Opioids include such drugs as codeine, fentanyl (Duragesic), hydromorphone (Dilaudid), meperidine (Demerol), morphine, oxycodone (OxyContin), and propoxyphene (Darvon). They are defined as Schedule II controlled substances by the Controlled Substances Act of 1970, which means that they have a high potential for abuse in addition to legitimate medical uses. A doctor must have a special license in order to prescribe opioids. In addition to the risk of abuse, opioids cause potentially serious side effects in some patients, including cognitive impairment (more common in the elderly), disorientation, constipation, nausea, heavy sweating, and skin rashes.

If the patient's pain is severe and persistent, the doctor will give separate dosages of opioids and NSAIDs in order to minimize the risk of side effects from high doses of aspirin or acetaminophen. In addition, the doctor may prescribe opioids that are stronger than codeine—usually morphine, fentanyl, or levorphanol.

The "WHO Ladder" for the treatment of cancer pain is based on the three levels of analgesic medication. Patients with mild pain from cancer are given nonopioid medications with or without an adjuvant (helping) medication. For example, the doctor may prescribe a tranquilizer to relieve the patient's anxiety as well as the pain medication. Patients on the second "step" of the ladder are given a milder opioid and a nonopioid analgesic with or without an adjuvant drug. Patients with severe cancer pain are given stronger opioids at higher dosage levels with or without an adjuvant drug.

Acute pain following surgery is usually managed with opioid medications, most commonly morphine sulfate (Astromorph, Duramorph) or meperidine (Demerol). In some cases, NSAIDs that are available in injectable form (such as ketorolac) are also used. Patient-controlled analgesia, or PCA, allows patients to control the timing and amount of pain medication they receive. Although there are oral forms of PCA, the most common form of administration involves an infusion pump that delivers a small dose of medication through an intravenous line when the patient pushes a button. The PCA pump is pre-programmed to deliver no more than an hourly maximum amount of the drug.

Some types of chronic pain are treated by injections in specific areas of the body rather than by drugs administered by mouth or intravenously. There are three basic categories of injections for pain management:

• Joint injections. Joint injections are given to treat chronic pain associated with arthritis. The most common medications used are corticosteroids, which suppress inflammation in arthritic joints, and hyaluronic acid, which is a compound found in the joint fluid of healthy joints.
• Soft tissue injections. These are given to reduce pain in trigger points (areas of muscle that are hypersensitive to touch) and bursae, which are small pouches or sacs containing tissue fluid that cushions pressure points between tendons and bones. When a bursa becomes inflamed—a condition called bursitis—the person experiences pain in the nearby joint. Corticosteroids are the drugs most often used in soft tissue injections, although the doctor may also inject an anesthetic into a trigger point in order to relax the muscle.
• Nerve blocks. Nerve blocks are injections of anesthetic around the fibers of a nerve to prevent pain messages relayed along the nerve from reaching the brain. They may be used to relieve pain in specific parts of the body for a short period; a common example of this type of nerve block is the lidocaine injections given by dentists before drilling or extracting a tooth. Some nerve blocks are injected in or near the spinal column to control pain that affects a larger area of the body; an example is the epidural injection given to women in labor or to patients with sciatica. A third type of nerve block is administered to block the sympathetic nervous system as part of pain management in patients with complex chronic pain syndromes.

Medications used to treat neuropathic pain include tricyclic antidepressants, anticonvulsant medications, selective serotonin reuptake inhibitors, topical creams containing capsaicin or 5% lidocaine, and diphenhydramine (Benadryl).

Surgery

Because surgery is itself a cause of pain, few surgical treatments to relieve pain were available prior to the discovery of safe general anesthetics in the mid-nineteenth century. For most of human history, doctors were limited to procedures that could be completed within two to three minutes because the patients could not bear the pain of the operation. Ancient Egyptian doctors gave their patients wine mixed with opium, while early European doctors made their patients drunk with brandy, tied them to the benches that served as operating tables, or put pressure on a nerve or artery to numb a specific part of the body.

Modern surgeons, however, can perform a variety of procedures to relieve either acute or chronic pain, depending on its cause. These procedures include:

• removal of diseased or dead tissue to prevent infection
• removal of cancerous tissue to prevent the spread of the cancer and relieve pressure on nearby healthy organs and tissues
• correction or reconstruction of malformed or damaged bones
• insertion of artificial joints or other body parts to replace damaged structures
• organ transplantation
• insertion of pacemakers and other electrical devices that improve the functioning of damaged organs or help to control pain directly
• cutting or destroying damaged nerves to control neuropathic pain

PSYCHOTHERAPY Psychotherapy may be helpful to patients with chronic pain syndromes by exploring the connections between anger, depression, or anxiety and physical pain sensations. One type of psychotherapy that has been shown to be effective is cognitive restructuring, an approach that teaches people to "reframe" the problems in their lives—that is, to change their conscious attitudes and responses to these stressors. Some psychotherapists teach relaxation techniques, biofeedback, or other approaches to stress management as well as cognitive restructuring.

Another type of psychotherapy that is effective in treating some patients with chronic pain is hypnosis. Although there is some disagreement among researchers as to whether hypnosis works by distracting the patient's attention from painful sensations or whether it works by stimulating the release of endorphins (chemicals produced by the body that are released in response to stress or injury and act as natural analgesics), it has been approved by the American Medical Association since 1958 as a treatment for pain. Some therapists offer instruction in self-hypnosis to patients with chronic pain.

COMPLEMENTARY AND ALTERNATIVE (CAM) APPROACHES CAM therapies that are used in pain management include:

• Acupuncture. Studies funded by the National Center for Complementary and Alternative Medicine (NCCAM) since 1998 have found that acupuncture is an effective treatment for chronic pain in many patients. It is thought that acupuncture works by stimulating the release of endorphins, the body's natural painkillers.
• Exercise. Physical exercise stimulates the body to produce endorphins.
• Yoga. Practiced under a doctor's supervision, yoga helps to maintain flexibility and range of motion in joints and muscles. The breathing exercises that are part of a yoga practice also relax the body.
• Prayer and meditation. The act of prayer by itself helps many people to relax. In addition, prayer and meditation are ways to refocus one's attention and keep pain from becoming the center of one's life.
• Naturopathy. Naturopaths include dietary advice and nutritional therapy in their treatment, which is effective for some patients suffering from chronic pain syndromes.
• Hydrotherapy. Warm whirlpool baths ease muscular and joint pain.
• Music therapy. Music therapy may involve listening to music, making music, or both. Some researchers think that music works to relieve pain by temporarily blocking the "gates" of pain in the dorsal horn of the spinal cord, while others believe that music stimulates the release of endorphins.

Pain management

Pain management refers to a set of skills and techniques for coping with chronic pain. The goal of pain management is not complete elimination of pain; rather, the patient learns to keep the pain at a level that he or she can tolerate, and to make the most of life in spite of the pain. The American Chronic Pain Association (ACPA) lists seven coping skills that help in managing pain:

• not dwelling on physical pain symptoms
• emphasizing abilities rather than disabilities
• recognizing one's feelings about the pain and discussing them freely
• using relaxation exercises to ease the emotional tension that makes pain worse.
• doing mild stretching exercises every day (with medical approval)
• setting realistic goals for improvement and evaluating them on a weekly basis
• affirming one's basic rights: the right to make mistakes, the right to say no, and the right to ask questions

An important part of pain management is participation in a multidisciplinary pain program. Many hospitals and rehabilitation centers in the United States and Canada offer pain management programs. Ideally, the program will have its own unit apart from patient care areas. Good pain management programs offer comprehensive treatment that includes relaxation training and stress management techniques; group therapy, family therapy, personal counseling, and job retraining; physical therapy, including exercise and body mechanics; patient education regarding medications and other aspects of pain management; and aftercare or follow-up support.

The treatment team in a pain management program is usually headed by a neurologist, psychiatrist, or anesthesiologist with specialized training in pain management. Other members of the team include registered nurses, psychiatrists or psychologists, physical and occupational therapists, massage therapists, family therapists, and vocational counselors.

Clinical trials

As of December 2003, the National Institutes of Health (NIH) was sponsoring 35 studies related to various chronic pain conditions and the effectiveness of such treatments as acupuncture, hypnosis, yoga, COX-2 inhibitors, and several experimental drugs.

Special concerns

Pain management in special populations

Pain management in the elderly and in children poses additional challenges. Although 20% of adults over 65 take an analgesic on a regular basis, older people are more vulnerable to the drug's side effects, particularly the nausea and bleeding that sometimes results from long-term use of NSAIDs. Children require special attention because they do not have an adult's ability to describe their pain. New tools have been developed since the mid-1990s to measure pain in children and to help doctors understand their nonverbal cues.

Addiction and withdrawal

Doctors have debated the risk of opioid abuse for most of the past century. For many years, patients with severe chronic pain were not given enough of the drugs they needed to control their pain because of the fear that they would become addicted to the narcotics. In the mid-1980s, however, some experts in pain management argued that the risk of addiction was quite low, whether the patients suffered from cancer pain or from chronic pain unrelated to cancer. As a result, some synthetic narcotics—most notably oxycodone (OxyContin)—were widely prescribed and a growing number of patients became addicted to these drugs. As of 2003, researchers estimate that 3–14% of the population may have an underlying undiagnosed vulnerability to abuse these substances.

In addition to the risk of abuse, there is a risk of withdrawal symptoms and a temporary increase in pain (known as rebound pain) if opioid medications are dis-continued suddenly. Withdrawal symptoms include diarrhea, runny nose and watery eyes, restlessness, insomnia, anxiety, nausea, and abdominal cramps. These symptoms are usually treated with clonidine (Catapres), an antihypertensive drug, and NSAIDs or antihistamines. The various risks of long-term use of opioids in pain management are not yet fully understood.

Resources

BOOKS

Altman, Lawrence K., MD. Who Goes First? The Story of Self-Experimentation in Medicine. Berkeley, CA: University of California Press, 1998.

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision. Washington, DC: American Psychiatric Association, 2000.

Martin, John H. Neuroanatomy: Text and Atlas, 3rd ed. New York: McGraw-Hill, 2003.

"Pain." The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Pain." New York: Simon & Schuster, 2002.

PERIODICALS

Daitz, Ben. "In Pain Clinic, Fruit, Candy and Relief." New York Times, December 3, 2002.

Duenwald, Mary. "Tales from a Burn Unit: Agony, Friendship, Healing." New York Times, March 18, 2003.

Halsey, James H., MD. "Atypical Facial Pain." eMedicine, February 9, 2001 (February 24, 2004). http://www.emedicine.com/neuro/topic25.htm.

Harstall, Christa, and Maria Ospina. "How Prevalent Is Chronic Pain?" Pain: Clinical Updates 11 (June 2003): 1–4.

Lasch, Kathryn E., PhD. "Culture and Pain." Pain: Clinical Updates 10 (December 2002): 1–11.

Meier, Barry. "The Delicate Balance of Pain and Addiction." New York Times, November 25, 2003.

Singh, Manish K., MD, Elizabeth Puscheck, MD, and Jashvant Patel, MD. "Chronic Pelvic Pain." eMedicine, November 7, 2003 (February 24, 2004). http://emedicine.com/med/topic2939.htm.

Wheeler, Anthony H., MD. "Therapeutic Injections for Pain Management." eMedicine, October 19, 2001 (February 24, 2004). http://www.emedicine.com/neuro/topic514.htm.

Wheeler, Anthony H., MD, James R. Stubbart, MD, and Brandi Hicks. "Pathophysiology of Chronic Back Pain." eMedicine, March 8, 2002 (February 24, 2004). http://www.emedicine.com/neuro/topic516.htm.

Yates, William R., MD. "Somatoform Disorders." eMedicine, November 20, 2003 (February 24, 2004). http://www.emedicine.com/med/topic3527.htm.

WEBSITES

http://www.Pain.com.

http://www.PartnersAgainstPain.com.

OTHER

National Institute of Neurological Disorders and Stroke (NINDS). "Pain—Hope Through Research." NIH Publication No. 01-2406. 2001. NINDS. "Chronic Pain Information Page." Bethesda, MD: NINDS, 2001. (February 24, 2004.) http://www.ninds.nih.gov/health_and_medical/pubs/migraineupdate.htm.

ORGANIZATIONS

American Academy of Neurology (AAN). 1080 Montreal Avenue, Saint Paul, MN 55116. (651) 695-2717 or (800) 879-1960; Fax: (651) 695-2791. memberservices@ aan.com. http://www.aan.com.

American Academy of Pain Medicine (AAPM). 4700 West Lake, Glenview, IL 60025. (847) 375-4731; Fax: (877) 734-8750. aapm@amctec.com. http://www.painmed.org.

American Chronic Pain Association. P. O. Box 850, Rocklin, CA 95677. (916) 632-3208 or (800) 533-3231. ACPA@ pacbell.net. http://www.theacpa.org.

American Pain Foundation. 201 North Charles Street, Suite 710, Baltimore, MD 21201-4111. (888) 615-PAIN. http://www.painfoundation.org.

International Association for the Study of Pain (IASP) Secretariat. 909 NE 43rd Street, Suite 306, Seattle, WA 98105-6020. (206) 547-6409; Fax: (206) 547-1703. iaspdesk@juno.com. http://www.iasp-pain.org.

NIH Neurological Institute. P. O. Box 5801, Bethesda, MD 20824. (301) 496-5751 or (800) 352-9424. http://www.ninds.nih.gov.

Rebecca J. Frey, PhD

Pain, especially in its acute form, is usually a reflection of a tissue-damaging or potentially tissue-damaging stimulus. There is a transmission system that conveys this information to the central nervous system. This phenomenon is called nociception. Pain is more complex than other sensory systems such as vision or hearing because it not only involves the transfer of sensory information to the nervous system, but produces suffering which then leads to aversive corrective behavior. In certain disease states, defects in the transmission system can of themselves generate false information to the nervous system, as though tissue damage were occurring in the periphery. An example of this is phantom limb pain, in which the individual often has a crushing type of pain in a foot that has been amputated.

Acute pain such as occurs with broken bones and other significant injuries is almost inevitably accounted for by the phenomenon of nociception and is probably a purely neurophysio-logical event. However, the more pain becomes a chronic phenomenon, the more such influences as psychological factors and behavior become part of the expression of pain.

Acute pain is a useful warning system. There are specific nerve paths for conducting this sensation (see illustration). Pain receptors in the skin and other tissues are nerve terminals which lack any special characteristics, and they are probably triggered by a chemical stimulus when potential tissue damage occurs. There appear to be two types of terminals: one responds to many types of painful stimuli, whereas the other specifically responds to either mechanical or thermal energy. When the terminals are stimulated, the pain (that is, nociception message) is carried along specific small sensory fibers called A-delta and C fibers. The A-delta fibers are larger and transmit the “first pain” or “fast pain” The smaller C fibers transmit a secondary dull continuous pain. These nerve fibers were traditionally believed to enter the spinal cord through the dorsal root, but it now seems that many also enter through the ventral root into the spinal cord.

Neurophysiology of incoming pain. Sensation from peripheral receptors travels along specific pain nerves, and is modulated throughout the spinal cord and brain.

Having entered the spinal cord, these fibers relay in the dorsal horn of the spinal gray matter, an area of considerable regulation and modulation of the incoming pain stimulus which is influenced by other incoming sensory stimuli; that is, touch or pressure sensations can suppress the transmission of signals in the small pain fibers. This helps to explain why when a person is hurting, the pain can be reduced by rubbing the affected part, and this phenomenon forms the basis of some of the treatment strategies of stimulation-produced analgesia. In addition, the incoming pain signal in the spinal cord is also modulated by descending signals from the brain. At times of anxiety, these pain signals may be augmented. From these relay stations in the dorsal horn, the pain signal is carried by two nerve paths up to the brain. The classical pathway is the spinothalamic tract, on the side of the spinal cord opposite to the incoming stimulus, and this leads to the posterior part of the thalamus in the brainstem, and from there nerve paths radiate the pain sensation to many parts of the cerebral cortex, where the pain is appreciated. In addition to this direct path, there is also a diffuse ascending path known as the spinoreticular tract which relays to many of the basal ganglia in the brain, and from there to areas of the brain connected with motivational and affective behavior such as the hippocampus and the cingulate gyrus. It is possible that narcotic analgesics exert some of their action on this ascending spinoreticular tract because these drugs tend to reduce the suffering aspects of pain, but still preserve many of the discriminative qualities so that individuals can still feel the pain, but it does not bother them so much. See also Analgesic; Narcotic.

Certain parts of the brainstem around the central canal appear to exert a strong inhibitory effect on incoming pain signals. Stimulation of these areas probably releases endorphins, which are morphinelike substances produced by the body and liberated at various sites on the incoming pain path to suppress these signals. See also Endorphins.

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The International Association for The Study of Pain has provided the following definition of pain, which is used world-wide amongst scientists and clinicians interested in pain.

Pain is ‘an unpleasant sensory and emotional experience associated with actual or potential damage, or described in terms of such damage. Pain is always subjective. Each individual learns the application of the word through experiences relating to injury in early life’.

Noxious stimulation of a part of the body gives rise to electrical activity in the nervous system, extending from the periphery to the brain. Receptors and pathways dedicated to the nerve impulses giving rise to pain are described as components of somatic sensation and of visceral sensation. That activity is modulated within the central nervous system, both within the dorsal horns of the grey matter of the spinal cord and at higher levels. In this manner the input to the brain generated by noxious stimulation peripherally may be enhanced, diminished, or even, under certain circumstances, abolished — for example, in the heat of battle or a game of football. Thus, although noxious stimulation occurs, pain may not be felt at the time; such a mechanism clearly has value for survival of the individual in certain cases.

Our understanding of the physiology of pain control owes a great deal to the work of Melzack and Wall of some thirty-five years ago. Respectively a psychologist/physiologist and neurophysiologist, they proposed the gate-control theory of pain, which brought together previous work on the role of the nervous system in the generation of pain. They stated that within the dorsal horn of the spinal cord there are transmission cells (‘Trans cell’ in the figure) and that, as a result of tissue damage and stimulation, nerve impulses pass to those cells, which project further nerve impulses to the brain, where pain is experienced. The level of activity of the transmission cells is controlled by small adjacent cells which either excite or inhibit them. In turn the level of activity of the smaller cells is determined by the extent to which they are stimulated by nerve impulses from the body or the brain. Large diameter nerve fibres (beta fibres), which are stimulated by touch, excite the small inhibitory cells (white circles in the figure) adjacent to the transmission cells. In contrast, tissue injury excites other (A delta and C) nerve fibres. The former are large diameter fibres which conduct rapidly and the latter are small diameter fibres which conduct slowly. Both stimulate the transmission cell and small excitatory cells (black circles in the figure). Therefore in an acute injury, for example when the thumb is struck by a hammer, the A delta and C fibre activity exceeds the activity in beta fibres and pain is felt. When the injured part is rubbed vigorously the pain lessens and it does so because rubbing the skin stimulates beta fibres to the point where their level of stimulation of the small inhibitory cells exceeds that of the stimulation by the A delta and C fibres of the small excitatory cells. As a result, the activity of the transmission cell is reduced or ceases. This mechanism is involved when clinicians use transcutaneous electrical nerve stimulation (TENS) to relieve pain. Neurons descending from the brain may also excite or inhibit activity of the transmission cells within the spinal cord by influencing the small adjacent excitatory and inhibitory cells. For example, in states of emotional calmness, inhibition of transmission cell activity occurs, and less pain is experienced than in states of anxiety, when the activity of the transmission cells is increased by stimulation of the small excitatory cells.

Gate-control theory of pain: the nerve pathways involved (see text)


In some situations pain may be felt when part of the body is missing, for example after the amputation of a limb or breast. Such ‘phantom pains’ are located in the absent part at a site where pain may have been felt before the part was lost. How then can pain, which is at times chronic and excruciating, be experienced in a limb that does not exist as a physical reality? The answer lies in the way the brain functions. Activity in areas of the brain concerned with sensory activity in the missing limb continues despite the absence of the limb, and gives rise to a phantom. If in addition central pain processes are active, phantom pain is experienced in the phantom limb. Such pain may be eliminated by stimulation of the sensory cerebral cortex but not by the division of nerves or the spinal cord. This supports the view that, although most people believe that pain actually exists at a site in the body that hurts, it is in fact a part of consciousness and the result of brain activity.

Until recently it was thought that the sensory and emotional elements of pain experience were linked solely to specific areas of the brain, namely the sensory and the emotional cortex, respectively. However, recent work using non-invasive brain imaging techniques — for example positron emission scanning — has revealed this model to be too simple. It is true that within the brain there is a degree of functional specialization for pain, but this is only part of the story. For example, damage to one half of the cerebral cortex does not necessarily abolish pain sensations from the opposite side of the body, and damage to areas of the brain associated with emotion does not necessarily remove the emotional component of pain. The reason for these apparent anomalies seems to lie in the fact that pain is generated within a widely distributed system or neuronal network. In this way, the brain detects tissue injury even when there is considerable damage to the nervous system. The brain functions as an active system, which filters, selects, and integrates sensory input against the background of lifelong experiences, both physical and emotional, which are preserved in the systems devoted to memory. One brain output from this process is pain.

Pain therefore occurs only in the conscious individual, and it is essential for survival. A small but unfortunate number of people are born without the capacity to feel pain. As a result they suffer horrific injuries in childhood and die young as a result of accidents or undiagnosed disorders, which in normal people give rise to pain.

In everyday life pain is recognized in two forms, namely acute pain and chronic pain. The former has a protective function. It alerts us to damage to the body, it increases our level of arousal, it directs our attention to the cause of the pain, and generates behaviour that leads to an escape from it. The chief emotion associated with acute pain is anxiety, and this subsides when pain is relieved and the cause is understood. In contrast, chronic pain does not appear to the sufferer to have any purpose and indeed has negative qualities. It gives rise to feelings of anxiety and at times of depression. The behaviours generated include withdrawal from social activities and a search for relief. The latter may well lead the sufferer to move from one doctor to another and to non-medical practitioners in the hope of pain relief. At times that process itself may generate more physical suffering through unnecessary investigation and the end result is pain, despair, and depression.

Both acute and chronic forms of pain are familiar, but in addition pain occurs in two other, quite different situations. It may occur as a symptom in a depressive illness. In other words it is not, as is commonly thought in such situations, that depression has developed because pain is being experienced but, in fact, the pain is part of a primary depressive illness. Up to half of those who develop depressive illnesses experience physical symptoms unrelated to any obvious underlying pathology, and of those symptoms pain is the most common. The failure of doctors to appreciate this fact does occasionally lead to a prolonged search for a physical cause for pain because its presence overshadows other features of a depressive illness.

Pain occurs in individual's experiencing anxiety, or emotional tension. For example, tension headaches are very common. The presence of anxiety in a pain sufferer tends both to increase the severity of pain experienced and to reduce the individual's tolerance or ability to cope with it.

Pain may occur in the absence of an obvious physical cause and where the features of a mental illness are not detectable. Individuals with this type of pain may have had a trivial injury but the level of pain and disability with which they present is out of all proportion to the severity of that injury. In addition, the behaviour shown by the sufferer reveals considerable dependence upon others, loss of willingness to take responsibility for themselves, their home, and their work, and a preoccupation with a search for a ‘cure’ for the pain, which they regard firmly as physical in origin.

Consideration of pain problems in which an underlying physical cause is either minimal or absent highlights the fact that when trying to understand pain it is necessary not only to consider its sensory aspects, but also its emotional ones. Indeed it has been said that to ignore the emotional aspects of pain is to look at only one part of the problem, and probably not the most important part at that. The definition of pain given earlier reinforces this point.

As a consequence of the need to encompass the physical, psychological, and social aspects of pain experience, clinicians and pain researchers have developed what is known as the biopsychosocial model of pain. It is based upon what we know about the generation and control of pain within the nervous system, and also its psychological aspects and the social factors that influence the thinking of individuals about pain and their behaviour. This approach to pain has lead to the development of powerful psychological tools for pain management, which come under the broad heading of cognitive-behavioural theory and practice.

Consideration of socio-cultural and learning factors reveals that learning about pain takes place within a definite social context, and the way each of us behaves when in pain reflects that fact. At a national level it is customary in general for those who are from Northern European countries to regard complaints about pain, especially amongst men, as a weakness of character. In contrast, in Southern European countries to complain about pain is regarded as beneficial to the sufferer. These are very broad generalizations but do have some basis in fact. An important psychological mechanism by which we learn the behaviours we exhibit when in pain is defined as operant learning. It is a process by which overt behavioural responses to a stimulus are significantly influenced by their consequences, including the responses of others to them.

Operant learning is well illustrated by the effects of a simple injection upon a child. The sight of the needle and the pain experienced is an ‘unconditioned stimulus’ and as a response to it the child cries. On the next occasion the child cries at the sight of the syringe and needle, which have become ‘the conditioned stimulus’. If crying leads to the abandonment of the injection the child has developed a ‘conditioned escape response’. Seeing another child crying before an injection which is then not given leads to another type of learning — ‘an observational learning model’.

In some individuals such mechanisms lead to the development of pain behaviours that have a negative effect upon their lives — for example, the excessive use of rest to relieve pain, or the abuse of powerful narcotic-related drugs may actually lead to increasing chronicity of pain and disability. To counter such developments psychologists have developed techniques based upon operant conditioning, which are designed to reverse maladaptive pain behaviours and to replace them by adaptive behaviours. In other words, their techniques involve the use of learning of behaviour designed to lead to coping with pain and everyday life rather than withdrawing from them. Put in simple terms, ‘good behaviour is rewarded and bad behaviour is punished’.

Operant conditioning has been criticized on the grounds that it does not take sufficient account of mental activity. In other words, individuals have thoughts about pain and attitudes towards it. They draw on memories of past experience when in pain, and this leads to thinking and behaviour, which is the result of those experiences. Such thoughts and attitudes, or cognitions, as they are called, cannot be ignored when a clinician is evaluating a person in pain and planning their treatment. For this reason, a purely behavioural approach has been replaced by a cognitive-behavioural approach to pain analysis and management. The main cognitive elements that have been identified include beliefs about pain and its causes, beliefs about the extent to which the individual feels he or she has control over pain, and the extent to which individuals believe that they are able to function despite pain. Therefore, self-efficiency is a significant factor in determining ability to cope.

People in pain often develop what are described by psychologists as ‘cognitive errors’. For example, they may indulge in what is known as ‘catastrophizing’. In other words they develop an unnecessarily negative view of their condition and its likely outcome. In such a state they tend to focus to a extent upon the negative features of their disorder. It has been demonstrated that negative qualities of thought, and catastrophizing in particular, are consistently linked to the development of depression in chronic pain disorders. The manipulation of coping mechanisms is of great significance when considering the management of pain and especially of chronic pain. We are all familiar with coping strategies, some of which are regarded as active — for example, indulging in active and distracting behaviour, whereas others are passive — for example, taking rest or medicines. If the strategy used maximizes function in the presence of pain and reduces anxiety, then it is said to be adaptive. On the other hand, if the strategies used involve too much rest, too great a dependence on medication or on others, or conversely too much activity which provokes excessive pain, they are maladaptive. Cognitive therapies involve changing thoughts and attitudes about pain with a view to changing self-management in the direction of adaptive behaviour: a change which often leads to a lessening of pain.

— Michael R. Bond

Bibliography

• Gatchell, R. J. and Turk, D. C. (ed.) (1996). Psychological approaches to pain management. The Guilford Press, New York and London.
• Main, J. C. and Spanswick, C. C. (2000) Pain management: an interdisciplinary approach. Churchill Livingstone, Edinburgh & London.
• Wall, P. (1999). Pain; the science of suffering. Weidenfeld and Nicolson, London

See also analgesia; central nervous system; endorphins; opiates and opioid drugs; somatic sensation; visceral sensation.

Scientists do not know exactly how we feel pain, but it involves the stimulation of specialized nerve-endings. Individuals vary in their sensitivity according to their pain threshold (minimum intensity of stimulation which can evoke pain) and pain tolerance (ability to put up with feelings of pain). Some chemical substances released in the body increase sensitivity. These include bradykinins, histamine, potassium, and serotonin, all of which may be released at sites of tissue damage.

Many sedentary people believe that all exercisers have to experience pain if they are to become fitter: this belief is encouraged by the well known training motto: ‘No pain, no gain’. Sensible people interpret this as meaning that it takes effort, dedication, and commitment to improve fitness; it does not mean that exercise has to be a masochistic ordeal. On the contrary, if real pain is experienced, an exerciser should stop. Of course, an athlete who is training for top-class competition must be able to tolerate greater discomfort than a recreational athlete, but even an elite athlete must learn to distinguish between real pain and discomfort. Real pain acts as an important warning signal that something is wrong. If the signal is ignored, serious injury may result.

Pain can be relieved by a variety of means including cold therapy (e.g. application of ice), acupuncture, transcutaneous nerve stimulation, and analgesic drugs. Used correctly, these can provide relief and accelerate recovery. However, used incorrectly they can make a bad condition even worse. Many injured athletes unwisely take painkillers to enable them to continue training or competing. This often leads to further damage and the need for stronger painkillers; a vicious cycle ensues which can only be broken by rest. See also muscle soreness.

[PAN] 1. French for "bread" or "loaf of bread". Various types of bread in France include: pain aux noix (nut bread), pain complet (whole wheat bread), pain d'épices (spiced or gingerbread), pain grillé (toasted bread), pain de mie (sliced, packaged white bread), pain ordinaire (peasant bread), pain perdu (french toast) and pain petit (roll). 2. The word pain is also used in France to describe a baked, molded loaf of forcemeat bound with a panade. Such a meat, poultry, fish or vegetable pain can be served hot, cold or at room temperature.

noun

1. A sensation of physical discomfort occurring as the result of disease or injury: ache, pang, prick, prickle, smart, soreness, stab, sting, stitch, throe, twinge. Informal misery. See pain/pleasure.
2. A state of physical or mental suffering: affliction, agony, anguish, distress, hurt, misery, torment, torture, woe, wound, wretchedness. See happy/unhappy.
3. Attentiveness to detail. care, carefulness, fastidiousness, meticulousness, painstaking, punctiliousness, scrupulousness, thoroughness. See careful/careless.
4. The use of energy to do something. effort, endeavor, exertion, strain¹, striving, struggle, trouble, while. Informal elbow grease. See work/play.
5. One that makes another totally miserable by causing sharp pain and irritation: thorn, trial. Idioms: pain in the neck, thorn in thefleshside. See pain/pleasure.

verb

1. To cause suffering or painful sorrow to: aggrieve, distress, grieve, hurt, injure, wound. See happy/unhappy.
2. To have or cause a feeling of physical pain or discomfort: ache, hurt, pang, twinge. See pain/pleasure.

Idioms beginning with pain:
pain in the neck
paint black
paint oneself into a corner
paint the town red

See also at pains; feel no pain; for one's pains; growing pains; no pain, no gain; on pain of.

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n

Definition: big problem
Antonyms: irritation

n

Definition: mental suffering
Antonyms: cheer, happiness, joy, pleasure, well-being

n

Definition: physical suffering
Antonyms: comfort, good health, health, well-being

v

Definition: bother, trouble
Antonyms: aid, assist, assuage, help, please

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Definition

Pain is an unpleasant feeling that is conveyed to the brain by sensory neurons. The discomfort signals actual or potential injury to the body. However, pain is more than a sensation, or the physical awareness of pain; it also includes perception, the subjective interpretation of the discomfort. Perception gives information on the pain's location, intensity, and something about its nature. The various conscious and unconscious responses to both sensations and perception, including the emotional response, add further definition to the overall concept of pain.

Description

Pain arises from any number of situations. Injury is a major cause, but pain may also arise from a wide variety of illnesses. It may accompany a psychological condition, such as depression, or may even occur in the absence of a recognizable trigger.

Acute Pain

Acute pain often results from ordinary tissue damage, such as a skin burn or broken bone. Acute pain can also be associated with headaches or muscle cramps. This type of pain usually goes away as the injury heals or the cause of the pain (stimulus) is removed.

To understand acute pain, it is necessary to understand the nerves that support it. Nerve cells, or neurons, perform many functions in the body. Although their general purpose, providing an interface between the brain and the body, remains constant, their capabilities vary widely. Certain types of neurons are capable of transmitting a pain signal to the brain.

As a group, these pain-sensing neurons are called nociceptors, and virtually every surface and organ of the body is wired with them. The central part of these cells is located in the spine, and they send threadlike projections to every part of the body. Nociceptors are classified according to the stimulus that prompts them to transmit a pain signal. Thermoreceptive nociceptors are stimulated by temperatures that are potentially tissue damaging. Mechanoreceptive nociceptors respond to a pressure stimulus that may cause injury. Polymodal nociceptors are the most sensitive and can respond to temperature and pressure. Polymodal nociceptors also respond to chemicals released by the cells in the area from which the pain originates.

Nerve cell endings, or receptors, are at the front end of pain sensation. A stimulus at this part of the nociceptor unleashes a cascade of neurotransmitters (chemicals that transmit information within the nervous system) in the spine. Each neurotransmitter has a purpose. For example, substance P relays the pain message to nerves leading to the spinal cord and brain. These neurotransmitters may also stimulate nerves leading back to the site of the injury. This response prompts cells in the injured area to release chemicals that not only trigger an immune response, but also influence the intensity and duration of the pain.

Chronic and Abnormal Pain

Chronic pain refers to pain that persists after an acute injury heals, cancer pain, pain related to a persistent or degenerative disease, and long-term pain from an unidentifiable cause. It is estimated that one in three people in the United States will experience chronic pain at some point in their lives. Of these people, approximately 50 million are either partially or completely disabled.

Chronic pain may be caused by the body's response to acute pain. In the presence of continued stimulation of nociceptors, changes occur within the nervous system. Changes at the molecular level are dramatic and may include alterations in genetic transcription of neurotransmitters and receptors. These changes may also occur in the absence of an identifiable cause; one of the frustrating aspects of chronic pain is that the stimulus may be unknown. For example, the stimulus cannot be identified in as many as 85% of individuals suffering lower back pain.

Other types of abnormal pain include allodynia, hyperalgesia, and phantom limb pain. These types of pain often arise from some damage to the nervous system (neuropathic). Allodynia refers to a feeling of pain in response to a normally harmless stimulus. For example, some individuals who have suffered nerve damage as a result of viral infection experience unbearable pain from just the light weight of their clothing. Hyperalgesia is somewhat related to allodynia in that the response to a painful stimulus is extreme. In this case, a mild pain stimulus, such as a pin prick, causes a maximum pain response. Phantom limb pain occurs after a limb is amputated; although an individual may be missing the limb, the nervous system continues to perceive pain originating from the area.

Causes & Symptoms

Pain is the most common symptom of injury and disease, and descriptions can range in intensity from a mere ache to unbearable agony. Nociceptors have the ability to convey information to the brain that indicates the location, nature, and intensity of the pain. For example, stepping on a nail sends an information-packed message to the brain: the foot has experienced a puncture wound that hurts a lot.

Pain perception also varies depending on the location of the pain. The kinds of stimuli that cause a pain response on the skin include pricking, cutting, crushing, burning, and freezing. These same stimuli would not generate much of a response in the intestine. Intestinal pain arises from stimuli such as swelling, inflammation, and distension.

Diagnosis

Pain is considered in conjunction with other symptoms and individual experiences. An observable injury, such as a broken bone, may be a clear indicator of the type of pain a person is suffering. Determining the specific cause of internal pain is more difficult. Other symptoms, such as fever or nausea, help narrow down the possibilities. In some cases, such as lower back pain, a specific cause may not be identifiable. Diagnosis of the disease causing a specific pain is further complicated by the fact that pain can be referred to (felt at) a skin site that does not seem to be connected to the site of the pain's origin. For example, pain arising from fluid accumulating at the base of the lung may be referred to the shoulder.

Since pain is a subjective experience, it may be very difficult to communicate its exact quality and intensity to other people. There are no diagnostic tests that can determine the quality or intensity of an individual's pain. Therefore, a medical examination will include a lot of questions about where the pain is located, its intensity, and its nature. Questions are also directed at what kinds of things increase or relieve the pain, how long it has lasted, and whether there are any variations in it. An individual may be asked to use a pain scale to describe the pain. One such scale assigns a number to the pain intensity. For example, 0 may indicate no pain, and 10 may indicate the worst pain the person could imagine. Scales are modified for infants and children to accommodate their level of comprehension.

Treatment

Both physical and psychological aspects of pain can be dealt with through alternative treatment. Some of the most popular treatment options include herbal therapies, nutritional therapies, homeopathy, acupressure and acupuncture, massage, chiropractic, guided imagery, and relaxation techniques, such as yoga, hypnosis, and meditation. Hydrotherapy can also be very beneficial for pain relief.

Herbal Therapies

Mild natural painkillers are used as herbal remedies for pain. They should only be used for mild to moderate chronic pain. However, unlike prescription drugs, they are not addictive and do not dull the senses. In addition, they can help heal the nervous system as well as relieving pain. The following herbal remedies have been known to provide pain relief:

• Capsaisin: is found naturally in cayenne pepper. (Its cream or gel form may be able to relieve some arthritic pain.)
• Bromelain: reduce inflammation.
• Curcumin: reduces inflammation.
• Kava kava: helps relax the body.
• Pine-bark and grape-seed extracts: reduces inflammation.
• Pain-relief tea: is composed of white willow bark, chamomile, skullcap, valerian root and licorice root. (This herbal preparation may be effective in relieving normal aches and pain. However, persons with high blood pressure or those allergic to aspirin should avoid using this preparation.)

Nutritional Therapy

Diet and nutrition can play important roles in controlling chronic pain. Patients with chronic pain sometimes find relief just by eating healthy foods and by adding nutritional supplements with pain-killing properties. A diet high in fiber and complex carbohydrates is recommended. Because inflammation is often caused by allergic reactions, patients should eliminate allergic foods from their diets. They should also avoid foods high in fats or margarine, red meat, dairy products, shellfish, alcohol, and coffee. In addition, they may consider taking one of the following nutritional supplements: flaxseed oil, bromelain, calcium taken with magnesium, vitamin C taken with bioflavonoids, and glucosamine. Glucosamine sulfate is one of the best natural remedies available for arthritic pain. Studies have shown that it effectively reduces pain and improves joint movement in 80% of arthritic patients. It works by healing and regenerating new connective tissues damaged by the inflammatory process. It may also increase the level of endorphins, the body's natural painkillers, and reduces inflammation in most arthritic patients. Recently, researchers also confirmed what thousands of people with arthritis have known for a long time — that cod liver oil eases the pain of arthritis. A new study says that the omega-3 fatty acids in cod liver oil break down joint cartilage, slowing destruction of the joints and easing pain. This has been good news for arthritis sufferers who can not tolerate the prescription drugs available for arthritis treatment.

Homeopathy

Depending on a patient's specific condition, a homeopathic physician may prescribe one of the following medications for pain management:

• Arnica: for treatment of acute pain after an injury.
• Hypericum: for treatment of pain in nerves, fingers or toes after injury or surgery.
• Ledum: for treatment of pain associated with black- and-blue bruises and puncture wounds.

Acupuncture

Acupuncture involves inserting needles at various points on the skin of the body. These needles direct chi (life force) to organs or functions of the body. This therapy possibly works by triggering the release of endorphins, therefore dulling the perception of pain. Acupuncture can effectively reduce most chronic pain. However, it may require up to 10 sessions before results are noticeable. A 2002 study showed that acupuncture worked well for chronic neck pain and range of motion, but that its long-term effects were limited. It is important that patients request disposable needles to prevent transmission of AIDS, hepatitis, and other infectious diseases.

Acupressure

There are some acupressure techniques that patients can train themselves to do to help relieve pain. Using thumbs or fingers to apply pressure at appropriate acupressure points in the body, a person can release muscular tension in the head, neck or shoulder; calm the nervous system and relieve painful symptoms. Like acupuncture, acupressure probably works by releasing endorphins.

Massage

Massage involves using physical manipulation techniques to make various parts of the body, such as muscles, connective tissues, and vertebrae, work together and function properly. This form of therapy may effectively reduce stress and physical pain.

Chiropractic

Chiropractors treat patients by manipulating joints and the spine. It is believed that pain, especially back pain, is caused by misalignment of the spine. This form of treatment is most effective in patients with persistent back pain and neck problems. It is also effective in patients with acute, uncomplicated low back pain.

Relaxation Therapy

Relaxation techniques include meditation, yoga, guided imagery, biofeedback, and hypnotherapy. When practiced regularly, these techniques have been shown to relax muscles and reduce tension and stress-related pain.

Lifestyle Changes

Lifestyles can be changed to include a healthier diet and regular exercise. Regular exercise, aside from relieving stress, has been shown to increase endorphins.

Hydrotherapy

This form of therapy uses hot and cold compresses, whirlpools, saunas, and alternating cold/warm showers or body wraps to reduce the soreness of aching joints, inflamed muscles, chronic muscle strains, and backache. Some of these treatments can be done at home.

Allopathic Treatment

There are many drugs aimed at preventing or treating pain. Nonopioid analgesics, narcotic analgesics, corticosteroids, anticonvulsant drugs, and tricyclic antidepressants work by blocking the production, release, or uptake of neurotransmitters. Nonopioid analgesics are used for treatment of minor pain. They include common over-the-counter medications such as aspirin, acetaminophen (Tylenol), and ibuprofen (Advil). Narcotic analgesics such as codeine, morphine, and methadone are used for more severe pain, such as cancer pain. These medications are available with a doctor's prescription. Initially developed to treat seizures and depression, some anticonvulsants and antidepressants now also have pain-killing applications. Finally, corticosteroid injections directly into or near the nerve that is transmitting the pain signal are reserved for intractable (unrelenting) pain that is not treatable by other medications.

Drugs are not always effective in controlling pain. Surgical methods are used as a last resort if drugs and local anesthetics fail. Electrode implants are the least destructive surgical procedure. However, this method may not completely control pain and is not used frequently. Other surgical techniques involve destroying or severing the nerve, but the use of this technique is limited by side effects, including unpleasant numbness.

Expected Results

Successful pain treatment is highly dependent on successful resolution of the pain's cause. Acute pain will stop when an injury heals or when an underlying problem is treated successfully. Chronic pain and abnormal pain are more difficult to treat, and it may take longer to find a successful resolution. Some pain is intractable and will require extreme measures for relief. In 2002, several health care organizations got together to form a panel charged with working on standards for evaluating effectiveness of pain management for patients who suffer from cancer, arthritis, and back pain. The standards will help physicians and others better measure patients' pain and effectiveness of pain management drugs and techniques.

Prevention

Pain is generally preventable only to the degree that the cause of the pain is preventable; diseases and injuries are often unavoidable. However, increased pain, pain from surgery and other medical procedures, and continuing pain are preventable through drug treatments and alternative therapies.

For many years, experts thought that arthritis patients should not exercise because it would damage their joints. However, a 2002 report said that regular low-impact exercise such as water aerobics or riding a stationary bicycle can actually help arthritic patients prevent pain.

Resources

Books

Adams, Raymond D., Maurice Victor, and Allan H. Ropper. Principles of Neurology. 6th ed. New York: McGraw-Hill, 1997.

Digeronimo, Theresa. The Natural Way of Healing: Chronic Pain New York, NY: The Philip Lief Group, 1995.

Tollison, C. David, John R. Satterthwaite, and Joseph W. Tollison, eds. Handbook of Pain Management. 2nd ed. Baltimore: Williams & Wilkins, 1994.

Zand, Janet, Allan N. Spreen and James B. LaValle. Smart Medicine for Healthier Living: A Practical A-to-Z Reference to Natural and Conventional Treatments for Adults. Garden City Park, NY: Avery Publishing Group, 1999.

Periodicals

Iadarola, Michael J., and Robert M. Caudle. "Good Pain, Bad Pain: Neuroscience Research." Science 278 (1997): 239.

Markenson, Joseph A. "Mechanisms of Chronic Pain." The American Journal of Medicine 101 (supplement 1A/1996): 6S.

"Pain Management Panel to Work on Standards." Hospice Management Advisor (March 2002): 36.

"Preventing Pain." American Fitness (March – April 2002): 13.

"Science Backs Cod Liver Oil." Immunotherapy Weekly (March 27, 2002): 4.

Sykes, J., R. Johnson, and G.W. Hanks. "Difficult Pain Problems: ABC of Palliative Care." British Medical Journal 315 (1997): 867.

Walling, Anne D. "Acupuncture Therapy for Chronic Neck Pain." American Family Physician (January 15, 2002): 310.

Organizations

American Chronic Pain Association. P.O. Box 850, Rocklin, CA 95677-0850. (916) 632-0922. http://members.tripod.com/~widdy/ACPA.html.

American Pain Society. 4700 W. Lake Ave., Glenview, IL 60025. (847) 375-4715. http://www.ampainsoc.org/.

[Article by: Mai Tran; Teresa G. Odle]

Definition

Pain is an unpleasant feeling that is conveyed to the brain by nerves in the body.

Description

Pain arises from any number of situations. Injury is a major cause, but pain may also arise from an illness. It may accompany a psychological condition, such as depression, or may even occur in the absence of a recognizable trigger. The discomfort signals actual or potential injury to the body. However, pain is more than a sensation or the physical awareness of pain; it also includes perception, the subjective interpretation of the discomfort. Perception gives information on the pain's location, intensity, and something about its nature. The various conscious and unconscious responses to both sensation and perception, including the emotional response, add further definition to the overall concept of pain.

Acute Pain

Acute pain often results from tissue damage, such as a skin burn or broken bone. Acute pain can also be associated with headaches or muscle cramps. This type of pain usually goes away as the injury heals or the cause of the pain (stimulus) is removed. To understand acute pain, it is necessary to understand the nerves that support it. Nerve cells, or neurons, perform many functions in the body. Although their general purpose, providing an interface between the brain and the body, remains constant, their capabilities vary widely. Certain types of neurons are capable of transmitting a pain signal to the brain. As a group, these pain-sensing neurons are called nociceptors, and virtually every surface and organ of the body is wired with them. The central part of these cells is located in the spine, and they send threadlike projections to every part of the body. Nociceptors are classified according to the stimulus that prompts them to transmit a pain signal. Thermoreceptive nociceptors are stimulated by temperatures that are potentially tissue damaging. Mechanoreceptive nociceptors respond to a pressure stimulus that may cause injury. Polymodal nociceptors are the most sensitive and can respond to temperature and pressure. Polymodal nociceptors also respond to chemicals released by the cells in the area from which the pain originates.

Nerve cell endings, or receptors, are responsible for pain sensation. A stimulus at this part of the nociceptor unleashes a cascade of neurotransmitters (chemicals that transmit information within the nervous system) in the spine. Each neurotransmitter has a purpose. For example, substance P relays the pain message to nerves leading to the spinal cord and brain. These neurotransmitters may also stimulate nerves leading back to the site of the injury. This response prompts cells in the injured area to release chemicals that not only trigger an immune response but also influence the intensity and duration of the pain.

Chronic and Abnormal Pain

Chronic pain refers to pain that persists after an injury heals, cancer pain, pain related to a persistent or degenerative disease, and long-term pain from an unidentifiable cause. It is estimated that one in three people in the United States experiences chronic pain at some point in their lives. Of these people, approximately 50 million are either partially or completely disabled. Chronic pain may be caused by the body's response to acute pain. In the presence of continued stimulation of nociceptors, changes occur within the nervous system. Changes at the molecular level are dramatic and may include alterations in genetic transcription of neurotransmitters and receptors. These changes may also occur in the absence of an identifiable cause; one of the frustrating aspects of chronic pain is that the stimulus may be unknown. For example, the stimulus cannot be medically identified in as many as 85 percent of individuals suffering from lower back pain.

Other types of abnormal pain include allodynia, hyperalgesia, and phantom limb pain. These types of pain often arise from some damage to the nervous system (neuropathic). Allodynia refers to a feeling of pain in response to a normally harmless stimulus. For example, some individuals who have suffered nerve damage as a result of viral infection experience unbearable pain from just the light weight of their clothing. Hyperalgesia is somewhat related to allodynia in that the response to a painful stimulus is extreme. In this case, a mild pain stimulus, such as a pinprick, causes a maximum pain response. Phantom limb pain occurs after a limb is amputated; although an individual may be missing the limb, the nervous system continues to perceive pain originating from the area.

Demographics

Pain is experienced by all age groups, both sexes, and all races and ethnic groups.

Causes and Symptoms

Pain is the most common symptom of injury and disease, and descriptions can range in intensity from a mere ache to unbearable agony. Nociceptors have the ability to convey information to the brain that indicates the location, nature, and intensity of the pain. For example, stepping on a nail sends an information-packed message to the brain: the foot has experienced a puncture wound that hurts a lot. Pain perception also varies depending on the location of the pain. The kinds of stimuli that cause a pain response on the skin include pricking, cutting, crushing, burning, and freezing. These same stimuli would not generate much of a response in the intestine. Intestinal pain arises from stimuli such as swelling, inflammation, and distension.

When to Call the Doctor

Parents should notify their physician or pediatrician if any of the following occurs:

• The child is in severe pain.
• The child has pain that lasts for more than three days.
• Parents have questions or concerns about their child's treatment or condition.
• The child is in the hospital and the parent thinks he or she is in pain. The sooner the pain is treated, the easier it is to control.

Diagnosis

Pain is considered in view of other symptoms and individual experiences. An observable injury, such as a broken bone, may be a clear indicator of the type of pain a person is suffering. Determining the specific cause of internal pain is more difficult. Other symptoms, such as fever or nausea, help narrow the possibilities. In some cases, such as lower back pain, a specific physiological cause may not be identified. Diagnosis of the disease causing a specific pain is further complicated by the fact that pain can be referred to (felt at) a skin site that does not seem to be connected to the site of the pain's origin. For example, pain arising from fluid accumulating at the base of the lung may be referred to the shoulder.

Since pain is a subjective experience, it may be very difficult to communicate its exact quality and intensity to other people. There are no diagnostic tests that can determine the quality or intensity of an individual's pain. Therefore, a medical examination includes a lot of questions about where the pain is located, its intensity, and its nature. Questions are also directed at what kinds of things increase or relieve the pain, how long it has lasted, and whether there are any variations in it. An individual may be asked to use a pain scale to describe the pain. One such scale assigns a number to the pain intensity; for example, 0 may indicate no pain, and 10 may indicate the worst pain the person has ever experienced. Scales are modified for infants and children to accommodate their level of comprehension.

A subsequent method of evaluating pain in children up to age four years was as of 2004 set to be implemented in 60 hospitals in the Netherlands. The Pain Observation Scale for Young Children, called POCIS, measures pain levels according to children's behavior in seven categories: facial expressions, crying, breathing, torso movements, movements in the arms and fingers and in the legs and toes, and restlessness. Physicians and nurses observe the intensity of these behaviors and calculate a pain severity score ranging from 0 to 7. Researchers from the University of Amsterdam who developed the scale said that existing behavioral pain measures were created for premature neonates or infants and may not be appropriate for older children. Some of those measures are upsetting for children because they require restraint or physical contact by a healthcare professional.

Alternative Treatment

Both physical and psychological aspects of pain can be dealt with through alternative treatment. Some of the most popular treatment options include acupressure and acupuncture, massage, chiropractic, and relaxation techniques, such as yoga, hypnosis, and meditation. Herbal therapies are increasingly recognized as viable options; for example, capsaicin, the component that makes cayenne peppers spicy, is used in ointments to relieve the joint pain associated with arthritis. Contrast hydrotherapy can also be very beneficial for pain relief. Lifestyles can be changed to incorporate a healthier diet and regular exercise. Regular exercise, aside from relieving stress, has been shown to increase endorphins, painkillers naturally produced in the body.

Prognosis

Successful pain treatment is highly dependent on successful resolution of the pain's cause. Acute pain will stop when an injury heals or when an underlying problem is treated successfully. Chronic pain and abnormal pain are more difficult to treat, and it may take longer to find a successful resolution. Some pain is intractable and requires extreme measures for relief.

Prevention

Pain is generally preventable only to the degree that the cause of the pain is preventable; diseases and injuries are often unavoidable. However, increased pain, pain from surgery and other medical procedures, and continuing pain are preventable through drug treatments and alternative therapies.

Parental Concerns

If a child has a lot of pain, it is likely that more can be done to help. The first step is for parents to tell the child's doctor or nurse what their concerns are. They can ask what more can be done for the child to control pain. If parents are still concerned about their child's pain control, they can request a meeting with the doctor. Parents should list their concerns as clearly as possible. They should take a constructive approach and seek to form a partnership with the healthcare team in managing the child's pain. For parents who are still not satisfied with what is being done, some type of formal complaint to the hospital may be unavoidable. Pain management is the right of every child. Parents working with health providers are the best advocates for this right. The U.S. Department of Health and Human Services Agency for Health Care Policy and Research has developed guidelines for pain management. These guidelines establish a standard of care that should be followed. Parents can get a copy from the hospital library or directly from the government.

Resources

Books

Lehman, Thomas J. It's Not Just Growing Pains: A Guide to Childhood Muscle, Bone, and Joint Pain, Rheumatic Diseases, and the Latest Treatments. Oxford, UK: Oxford University Press, 2004.

McGrath, Patrick J., and Allen G. Finley. Pediatric Pain: Biological and Social Context. Seattle, WA: IASP Press, 2003.

Schechter, Neil L., et al. Pain in Infants, Children, and Adolescents, 2nd ed. New York: Lippincott Williams & Wilkins, 2002.

Periodicals

Leung, Alexander K. C., and David L. Sigalet. "Acute Abdominal Pain in Children." American Family Physician (June 1, 2003): 2321.

O'Rourke, Deborah. "The Measurement of Pain in Infants, Children, and Adolescents: From Policy to Practice." Physical Therapy (June 2004): 560–70.

Springen, Karen. "Small Patients, Big Pain: Ten Million American Children Suffer Chronic or Recurrent Pain. Treating Them Poses Special Challenges. Now Doctors and Researchers are Learning How to Help." Newsweek (May 19, 2003): 54.

Tanne, Janice Hopkins. "Children Are Often Undertreated for Pain." British Medical Journal (November 22, 2003): 1185.

Williams, Mathew E. "Trouble Underfoot: Heel Pain in Children: Practitioners Must Have a High Index of Suspicion and Conduct a Thorough Workup to Determine the True Cause of a Child's Symptoms." Biomechanics (July 1, 2004): 26.

Organizations

American Chronic Pain Association. PO Box 850, Rocklin, CA 95677. Web site: www.theacpa.org.

American Pain Society. 4700 W. Lake Ave., Glenview, IL 60025. Web site: www.ampainsoc.org.

Web Sites

Rutherford, Kim. "The Truth about Pain." KidsHealth, August 2001. Available online at www.kidshealth.org/parent/general/aches/pain.html (accessed November 22, 2004).

Suresh, Santhanam. "Chronic Pain Management in Children and Adolescents." The Child's Doctor, 2004. Available online at www.childsdoc.org/spring2002/chronicpain.asp (accessed November 22, 2004).

Other

Carr, Daniel B., and Ada Jacox. "Acute Pain Management: Operative or Medical Procedures and Trauma; Clinical Practice Guideline." Available free by writing to AHCPR Publications Clearinghouse, PO Box 8547, Silver Spring, MD 20907. Available online at www.ahrq.gov/clinic/medtep/acute.htm (accessed November 22, 2004).

[Article by: Julia Barrett
Ken R. Wells]

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A favourite example of an experience that seems to resist reduction in terms of behaviour. Although pain obviously has behavioural consequences, being unpleasant, disruptive, and sometimes overwhelming, there is also something more than behaviour, something ‘that it is like’ to be in pain, and there is all the difference in the world between pain behaviour accompanied by pain and the same behaviour without pain. Theories identifying pain with neural events subserving it have been attacked (e.g. by Kripke) on the grounds that whilst a genuine metaphysical identity should be necessarily true, the association between pain and any such event would be contingent. See also mind-body problem, qualia.

A feeling of distress, suffering, or agony usually caused by the stimulation of specialized nerve endings. Pain has a protective function, acting as a warning sign and preventing further injury. However, even mild pain can have a detrimental effect on performance and severe pain will limit movement. Pain can be classified functionally into five levels: at level 1, pain occurs only after a specific activity; at level 2, pain occurs during and after specific activities, but it does not affect performance; at level 3, pain occurs during and after specific activity, and affects the performance of the activity; at level 4, pain occurs with activities of daily living; at level 5, pain occurs at rest. This classification enables an athlete to describe their pain to a physician. Also, during rehabilitation from a sports injury, the functional level of pain can be used as a guide to how recovery is progressing. Pain can be relieved by acupuncture, ice treatment, heat treatment, anaesthetics, anti-inflammatory medicines, analgesics NSAIDs, opiates, and transcutaneous nerve stimulation therapy. Substances that increase sensitivity to pain include bradykinins, free radicals, histamine, potassium, and serotonin. Some of these substances evoke pain by affecting nerves directly, others cause an inflammatory reaction. See also adaptive pain, maladaptive pain.

The term "pain" refers to a physical sensation or a distress linked to instinctual tension, which the psychic apparatus then seeks to discharge by work according to the principle of pleasure/unpleasure.

Jean-Bertrand Pontalis (1981) noted that the outline for an original theory of pain can be found in Freud's work from "A Project for a Scientific Psychology" (1950c [1895]) onward. Taken up again in Inhibitions, Symptoms, and Anxiety (1926d [1925]), this theory covers the basic reference points of analytic theory: the theory of narcissism, the question of trauma, the definition of primary masochism, and the presentation of the death instinct. Finally, with the concept of negative therapeutic reaction in place, Freud, in The Ego and the Id (1923b), described how pain drives resistance to analysis, indeed, how pain is the final refuge from renouncing the lost object, as the resistance implies.

By 1895 Freud had postulated bipolarity as the principle of psychic functioning, and, anticipating his later theory of instinctual dualism, he opposed the experience of pain to the experience of satisfaction. In qualitative terms, pain is different from unpleasure in that pain is situated outside the economic apparatus of pleasure/unpleasure. In dynamic terms, "[p]ain is . . . characterized as an irruption of excessively large Qs [quantities] into N [neurones that don't retain quantities of energy] and R [neurones that do retain energy and are capable of retaining memory" (1950c, p. 307). Then the body discharges the accumulated excitation. Pain can cause the subject to break out of preestablished paths only because there are boundaries (bodily boundaries, ego boundaries); however, its internal discharge has an implosive effect. Like a physical or psychic hole (to be distinguished from a possible lacuna or a lack), the excess of excitation caused by pain obstructs all binding activity. Pontalis (1981) has stressed that this theory of pain breaching is a departure from the economic apparatus where the theory of anxiety is more generally situated.

In 1926, in addendum C to Inhibitions, Symptoms and Anxiety, Freud again tried to differentiate pain from anxiety, though not without difficulty or contradiction. Pain is primarily a reaction to the loss of the object, whereas anxiety is a reaction to the danger that loss entails. Pain is the consequence of a breaching of the protective shield, and by acting as a constant instinctual excitation (some authors have proposed the idea of a pseudo-instinct here), it prevents the subject from escaping from it. Nonetheless, pain has a locus: it emanates from the periphery of the body or the organs. If anxiety has already led the subject to regard the loss of the object metaphorically, the unmediated reality of pain ensures that the subject can survive without the loss of the object or the nostalgia of that loss. In a third stage of his exposition in addendum C, Freud returns to the difference between mental pain and physical pain, arguing that the former is much more closely related to the mechanism of anxiety. "The transition from physical pain to mental pain corresponds to a change from narcissistic cathexis to object-cathexis. An object-presentation which is highly cathected by instinctual need plays the same role as a part of the body which is cathected by an increase of stimulus" (1926d, pp. 171-172).

Freud thus uses the same model to describe both physical pain and psychic pain. As Pontalis has made clear, pain is not a case of metaphor but rather a case of analogy—a direct exchange between one level and another, as if with pain the body mutates into psyche and the psyche into body. But while anxiety can be communicated, pain cannot. Despite a scream of pain, the cry does nothing to ease it. The experience of pain takes place within a bodily ego. Both physical pain and mental pain partake of the content-container relationship (Enriquez, 1980; McDougall, 1978). The subject in pain finds it impossible to recover the object by means of representation: "Where there is pain, it is the lost, absent object that is present; the real, present object that is absent." The distinctive feature of pain is its blurring of boundaries. Thus, for example, certain types of physical suffering serve to alleviate mental pain. Recent clinical work on somatization and borderline states is often faced with this inchoate nature of pain: absolute, naked pain.

Bibliography

Enriquez, Micheline. (1980). Du corps de souffrance au corps en souffrance. Topique, 26, 5-27.

Freud, Sigmund. (1923b). The ego and the id. SE, 19: 1-66.

——. (1926d [1925]). Inhibitions, symptoms, and anxiety. SE, 20: 75-172.

——. (1950c [1895]). A project for a scientific psychology. SE, 1: 281-387.

McDougall, Joyce. (1978). Plaidoyer pour une certaine anormalité. Paris: Gallimard.

Pontalis, Jean-Bertrand. (1981). Frontiers in psychoanalysis: Between the dream and psychic pain (Catherine Cullen and Philip Cullen, Trans.). London: Hogarth Press and the Institute of Psycho-Analysis. (Original work published 1977)

—DRINA CANDILIS-HUISMAN

Pain research and therapy have long been dominated by specificity theory which proposes that pain is a specific sensation subserved by a straight-through transmission system, and that the intensity of pain is proportional to the extent of tissue damage. Recent evidence, however, shows that pain is not simply a function of the amount of bodily damage alone, but is influenced by attention, anxiety, suggestion, prior experience, and other psychological variables (Melzack and Wall 1982). Moreover, the natural outcome of the specificity concept of pain has been the development of neurosurgical techniques to cut the so-called pain pathway, and the results of such operations have been disappointing, particularly for chronic pain syndromes. Not only does the pain tend to return in a substantial proportion of patients, but new pains may appear. The psychological and neurological data, then, forces us to reject the concept of a single straight-through sensory transmission system.

In recent years the evidence on pain has moved in the direction of recognizing the plasticity and modifiability of events in the central nervous system. Pain is a complex perceptual and affective experience determined by the unique past history of the individual, by the meaning to him of the injurious agent or situation, and by his 'state of mind' at the moment, as well as by the sensory nerve patterns evoked by physical stimulation.

In the light of this understanding of pain processes, Melzack and Wall (1965) proposed the gate control theory of pain. Basically, the theory states that neural mechanisms in the dorsal horn of the spinal cord act like a gate which can increase or decrease the flow of nerve impulses from peripheral fibres to the spinal cord cells that project to the brain. Somatic input is therefore subjected to the modulating influence of the gate before it evokes pain perception and response. The theory suggests that large-fibre inputs (such as gentle rubbing) tend to close the gate while small-fibre inputs (such as pinching) generally open it, and that the gate is also profoundly influenced by descending influences from the brain. It further proposes that the sensory input is modulated at successive synapses throughout its projection from the spinal cord to the brain areas responsible for pain experience and response. Pain occurs when the number of nerve impulses that arrive at these areas exceeds a critical level.

Melzack and Wall (1982) have recently assessed the present-day status of the gate control theory in the light of new physiological research. It is apparent that the theory is alive and well despite considerable controversy and conflicting evidence. Although some of the physiological details may need revision, the evidence supporting the concept of gating (or input modulation) is stronger than ever.

The subjective experience of pain clearly has sensory qualities, such as are described by the words throbbing, burning, or sharp. In addition, it has distinctly unpleasant, affective qualities which are described by words such as exhausting, wretched, and punishing. Pain becomes overwhelming, demands immediate attention, and disrupts ongoing behaviour and thought. It motivates or drives the organism into activity aimed at stopping the pain as quickly as possible. On the basis of these considerations, Melzack and Casey (1968) have proposed that there are three major psychological dimensions of pain experience: sensory–discriminative, motivational–affective, and cognitive–evaluative. Psychophysiological evidence suggests that each is subserved by specialized systems in the brain which interact to produce the multidimensional qualities of pain experience.

Recent recognition of the complexity of pain experience has led to the development of a paper-and-pencil questionnaire (the 'McGill Pain Questionnaire') to obtain numerical measures of the intensity and qualities of pain (Melzack 1975). The questionnaire consists of twenty sets of words that people use to describe pain. Ten sets describe sensory qualities, five describe affective qualities, and one is an evaluative group. Four sets consist of miscellaneous words. Since each word has a numerical value, patients asked to check those words that best describe their pain provide quantitative measures for each of the major dimensions of pain. The power of the questionnaire has been demonstrated in many quantitative, controlled studies of the effects of different forms of pain therapy (Melzack 1983). In addition, the questionnaire has been shown to discriminate among different types of pain. Distinctive patterns of words discriminate between migraine and tension headaches, between low-back pain of organic and that of functional origin, and between dysmenorrhoea and pain caused by an intra-uterine device.

Drugs, especially opium and its derivatives, are among the oldest methods for controlling pain. Thomas Sydenham in 1680 wrote: 'Among the remedies which it has pleased Almighty God to give to man to relieve his sufferings, none is so universal and efficacious as opium.' Since then, more effective derivatives of opium, notably morphine and heroin, have been discovered. The invention of the hypodermic needle and syringe not only stimulated the search for pure, injectable analgesics but also, unfortunately, increased the risk of drug dependence. The quest for preparations free from addictive properties has proved to be fruitless, but withholding such pain-relieving drugs from the terminally ill lest they become 'addicted' is as ridiculous as it is inhumane. Other drugs said to have analgesic properties include the antidepressants, but it does not appear that relief of depression is their mode of action. Possibly this may be by blocking the reuptake of serotonin and so potentiating the effect of enkephalins in the brain (see neuropeptides).

Many new methods to control pain have been developed in recent years (Melzack and Wall 1982). Sensory modulation techniques such as transcutaneous electrical nerve stimulation (TENS) and ice massage are widely used in the attempt to activate inhibitory neural mechanisms to suppress pain. These techniques have a long history but were not understood until recently. Acupuncture, for example, is an ancient Chinese medical procedure in which long needles are inserted into specific points at the skin. The traditional Chinese explanation is that the needles bring yin and yang (which flow through hypothetical tubules called meridians) into harmony with each other. It has been discovered, however, that the sites of insertion correspond to myofascial 'trigger points' which are well known in Western medicine. It has also been found that acupuncture and electrical stimulation through electrodes placed on the skin (TENS) are equally effective in relieving low-back pain and several other forms of pain, including pains due to peripheral nerve injury. The neural mechanisms which underlie the relief produced by these forms of stimulation are not entirely understood, but evidence suggests that the intense stimulation produced by acupuncture or TENS activates an area in the brain which exerts a powerful inhibitory control over pathways that transmit pain signals.

Psychological techniques that allow patients to achieve some degree of control over their pain have also been developed. These techniques include biofeedback, hypnosis, distraction, and the use of imagery and other cognitive activities to modulate the transmission of the nerve-impulse patterns that subserve pain. Psychological techniques are being used increasingly and provide relatively simple, safe approaches to pain control. They represent a significant advance over the earlier tendency to treat pain by neurosurgical operations intended to cut the 'pain pathway' and which so frequently ended in failure.

The techniques of sensory modulation and psychological control work well in conjunction with each other. A large body of research demonstrates that several of these procedures employed at the same time — 'multiple convergent therapy' — are often highly effective for the control of chronic pain states, particularly those such as low-back pain which have prominent elements of tension, depression, and anxiety.

While great strides have been made in the control of pain, there are still many pain syndromes which are beyond our comprehension and our control. Back pains, especially of the lower back, are the most common kind of pain, and literally millions of sufferers are continually seeking help. Sometimes they obtain temporary relief, but most continue to suffer. Migraine and tension headaches similarly plague millions of people. Perhaps the most terrible of all pains are those suffered by some cancer patients in the terminal phases of the disease. In recent years, specialized medical units have been developed to cope with these problems. Their major feature is that physicians and other health professionals from many different disciplines work together in the attempt to alleviate the pain of each individual patient. Pain clinics have been set up in every major Western city to cope with benign chronic pain, and hospices or palliative care units in hospitals have been developed to control pain (and other miseries) of patients who are terminally ill with cancer.

The development of pain clinics and hospices represents a breakthrough of the highest importance in the clinical control of pain. They are radical, new approaches to old problems. Chronic pain and terminal pain are major challenges to the scientist and clinician. But the giant step has been the recognition that they are special problems. The challenges ahead are clear: to conquer pain and suffering in all their forms.

(Published 1987)

See also anaesthesia.

— Ronald Melzack

Bibliography
• Dickenson, A. H. (2002). 'Gate Control Theory of pain stands the test of time'. British Journal of Anaesthesia, 88/6.
• Melzack, R. (1975). 'The McGill Pain Questionnaire: major properties and scoring methods'. Pain, 1.
• — —  (ed.) (1983). Pain Measurement and Assessment.
• — —  and Casey, K. L. (1968). 'Sensory, motivational and central control determinants of pain: a new conceptual model'. In Kenshalo, D. (ed.), The Skin Senses.
• — —  and Wall, P. D. (1965). 'Pain mechanisms: a new theory'. Science, 150.
• — —   — —  (1982). The Challenge of Pain.
• Wall, P. (1999). Pain, the Science of Suffering.

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A feeling of distress, suffering or agony, caused by stimulation of specialized nerve endings. Its purpose is chiefly protective; it acts as a warning that tissues are being damaged and induces the sufferer to remove or withdraw from the source.
All receptors for pain stimuli are free nerve endings of groups of myelinated or unmyelinated neural fibers abundantly distributed in the superficial layers of the skin and in certain deeper tissues such as the periosteum, surfaces of the joints, arterial walls, and the falx and tentorium of the cranial cavity. The distribution of pain receptors in the gastrointestinal mucosa apparently is similar to that in the skin; thus, the mucosa is quite sensitive to irritation and other painful stimuli. Although the parenchyma of the liver and the alveoli of the lungs are almost entirely insensitive to pain, the liver as an organ and the bile ducts are extremely sensitive, as are the bronchi, ureters, parietal pleura and peritoneum.
Some pain receptors are selective in their response to stimuli, but most are sensitive to more than one of the following types of excitation: (1) mechanical stress of trauma; (2) extremes of heat and cold; and (3) chemical substances, such as histamine, potassium ions, acids, prostaglandins, bradykinin and acetylcholine.
The conscious perception of pain probably takes place in the thalamus and lower centers; interpretation of the quality of pain is probably the role of the cerebral cortex.
There are some naturally occurring internal systems in the body that are known to control pain but none of them has been completely verified. One of the best known is the gate control system in which it is thought that pain impulses are mediated in the substantia gelatinosa of the spinal cord.

• abdominal p. — pain occurring in the area between the thorax and pelvis. Manifestations vary between species. Identifiable syndromes include: (1) horse—pawing, flank watching, rolling, straddling as though to urinate, lying on the back; (2) cattle—may depress back and paddle with hindfeet but mostly arched back, grunting, immobility; (3) dogs and cats—arched back, grunting, depression, reluctance to move. Sometimes there is elevation of the hindquarters, with the chest and forelegs on the ground (the so-called ‘praying dog’ attitude).
• Beagle p. syndrome — see beagle pain syndrome.
• projected p. — pathology in one area can affect the nerve supply to a distant area in which pain is experienced.
• p. receptors — free nerve endings of tufts of fine points or buttons.
• referred p. — pain felt in an area distant from the site of pathology but not mediated through a common innervation. There is no evidence that referred pain occurs in animals but it seems likely on anatomical grounds.
• p. threshold — the lowest level at which a stimulus can be applied and cause perceptible pain.
• p. tolerance — the level of stimulation at which pain becomes intolerable.

A cynical view of the world by Ambrose Bierce

n.

An uncomfortable frame of mind that may have a physical basis in something that is being done to the body, or may be purely mental, caused by the good fortune of another.

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IN BRIEF: n. - A somatic sensation of acute discomfort; Emotional distress.

We cannot learn without pain. — Aristotle

Quotes:

"Who, except the gods, can live time through forever without any pain?" - Aeschylus

"The injuries we do and the injuries we suffer are seldom weighed on the same scales." - Aesop

"The greatest evil is physical pain." - St. Augustine

"The moment an ill can be patiently handled, it is disarmed of its poison, though not of its pain." - Henry Ward Beecher

"And God shall wipe away all tears from their eyes; and there shall be nor more death, neither sorrow nor crying, neither shall there be any more pain. [Revelation]" - Bible

"To banish cares, scare away sorrow and soothe pain is the business of the poet and singer." - Bodenstedt

See more famous quotes about Pain

Experiencing pain in one's dream may be a reflection of real pain that exists somewhere in the dreamer's body. Alternatively, the dreamer may consider someone or something to be a "pain." The suppression of painful memories may also be an issue.

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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

Dansk (Danish)
n. - smerte
v. tr. - smerte, bedrøve
v. intr. - gøre ondt

idioms:

• be at pains to    gøre sig umage med
• feel no pain    ingen smerte føle
• for one's pains    for ens umage
• go to great pains    gøre sig meget umage
• on pain of    under straf af
• pain barrier    smertetærskel
• pain in the arse    en lort
• pain in the neck    en irriterende person
• under pain of    med straf af

Nederlands (Dutch)
pijn, lastpost, emotionele leed, verdriet doen, pijn doen

Français (French)
n. - douleur, mal, casse-pieds, sous peine de
v. tr. - faire mal, chagriner
v. intr. - faire souffrir, chagriner

idioms:

• be at pains to    prendre grand soin de (faire qch)
• feel no pain    (lit) ne ressentir aucune douleur, (US, fig) être soûl
• for one's pains    pour sa peine
• go to great pains    se donner beaucoup de mal pour
• on pain of    sous peine de
• pain barrier    seuil de la douleur
• pain in the arse    (US) (être) emmerdant
• pain in the neck    (GB) (être) casse-pieds
• under pain of    sous peine de

Deutsch (German)
n. - Schmerz, Plage, Mühe
v. - schmerzen

idioms:

• be at pains to    sich Mühe geben
• feel no pain    keinen Schmerz fühlen
• for one's pains    für jmds. Bemühungen
• go to great pains    sich sehr anstrengen
• on pain of    unter Androhung von
• pain barrier    Schmerzgrenze
• pain in the arse    einem auf den Nerv gehen
• pain in the neck    Nervensäge
• under pain of    unter Androhung von

Ελληνική (Greek)
n. - πόνος, οδύνη, (πληθ.) κόπος, στεναχώρια, βάσανα
v. - προξενώ πόνο, πονώ, λυπώ, στενοχωρώ, θλίβω

idioms:

• be at pains to    αγωνίζομαι να
• feel no pain    δεν νιώθω πόνο
• for one's pains    για τον κόπο μου
• go to great pains    αγωνίζομαι
• on pain of    με τιμωρία, επί ποινή
• pain barrier    οδυνηρή δοκιμασία (για παίκτη που παίζει παρά τον τραυματισμό του)
• pain in the arse    φόρτωμα, κακός μπελάς, σπαζαρχίδης
• pain in the neck    φόρτωμα, κακός μπελάς, σπαζαρχίδης
• under pain of    υπό ποινή

Italiano (Italian)
addolorare, dolore, pena, male, sofferenza

idioms:

• be at/take pains    fare di tutto per, darsi pena, affannarsi
• feels no pain    é insensibile, é indolore
• for one's pains    in compenso
• give a pain    dar fastidio
• go to great pains    far tutto il possibile
• on/under pain of    su pena di
• pain barrier    limite di sopportazione, soglia del dolore
• pain in the arse/backside    rompiscatole
• pain in the neck    rompiscatole
• spare no pains    mettercela tutta

Português (Portuguese)
n. - dor (f), sofrimento (m), esforço (m), castigo (m)
v. - doer

idioms:

• be at/take pains    esforçar-se
• feels no pain    meio bêbado (coloq.)
• for one's pains    por causa de alguém
• give a pain    punir
• go to great pains    esforçar-se muito
• on/under pain of    sob pena de
• pain barrier    limiar de dor
• pain in the arse/backside    desagradável, irritante
• pain in the neck    irritante, chato (coloq.)
• spare no pains    não medir esforços

Русский (Russian)
испытывать боль, причинять боль, боль

idioms:

• be at/take pains    стараться, усердствовать
• feels no pain    пьяный в стельку, мертвый
• for one's pains    в награду за труды
• give a pain    досаждать, надоедать
• go to great pains    стараться изо всех сил
• on/under pain of    под страхом
• pain barrier    болевой барьер
• pain in the arse/backside    головная боль, зануда
• pain in the neck    головная боль, зануда
• spare no pains    не жалеть сил

Español (Spanish)
n. - dolor, sufrimiento, pena
v. tr. - doler, dar lástima, apenar, afligir
v. intr. - doler, dar lástima, apenar, afligir

idioms:

• be at pains to    hacer grandes esfuerzos, darse mucho trabajo, tomarse el trabajo de
• feel no pain    borracho como una cuba, no sentir dolor
• for one's pains    lo único que logró como recompensa
• go to great pains    afanarse, empeñarse, esmerarse
• on pain of    so pena de
• pain barrier    umbral del dolor
• pain in the arse    inaguantable, fastidioso al máximo
• pain in the neck    ser un pesado, ser una lata
• under pain of    so pena de

Svenska (Swedish)
n. - smärta, värk, plåga, (pl.) besvär, omak, möda, straff, sorg, ängslan
v. - plåga, värka, svida

中文（简体）(Chinese (Simplified))
痛苦, 辛苦, 疼痛, 使烦恼, 使痛苦, 使疼痛, 引起疼痛, 感到疼痛

idioms:

• be at pains to    尽心于..., 费尽苦心于..., 努力于...
• feel no pain    不觉得痛
• for one's pains    尽管费尽力气
• go to great pains    费大力
• on pain of    违则以...处罚
• pain barrier    痛苦障限
• pain in the arse    讨厌的人或事, 麻烦的事或人, 屁股疼
• pain in the neck    讨厌的人或事, 麻烦的事或人, 脖子疼
• under pain of    违者则处以...的处罚

中文（繁體）(Chinese (Traditional))
n. - 痛苦, 辛苦, 疼痛
v. tr. - 使煩惱, 使痛苦, 使疼痛
v. intr. - 引起疼痛, 感到疼痛

idioms:

• be at pains to    盡心於..., 費盡苦心於..., 努力於...
• feel no pain    不覺得痛
• for one's pains    儘管費盡力氣
• go to great pains    費大力
• on pain of    違則以...處罰
• pain barrier    痛苦障限
• pain in the arse    討厭的人或事, 麻煩的事或人, 屁股疼
• pain in the neck    討厭的人或事, 麻煩的事或人, 脖子疼
• under pain of    違者則處以...的處罰

한국어 (Korean)
n. - 아픔, 노력
v. tr. - 괴롭히다, 비탄에 잠기게 하다
v. intr. - 아프다, 괴로워하다

idioms:

• be at pains to    애써서 ~ 하다
• go to great pains    ~하려고 매우 애쓰다
• under pain of    죽음을 당한다는 조건으로

日本語 (Japanese)
n. - 苦痛, 痛み, 骨折り, 陣痛, 苦しみ
v. - 苦痛を与える, 心痛させる, 困らせる, 痛む, 心配させる

idioms:

• be at/take pains    骨折っている
• feels no pain    酔っ払っている
• for one's pains    骨折り賃に, 骨折りがいもなく
• on/under pain of    ～の罰をもって
• pain barrier    苦痛障害
• pain in the arse/backside    泣きっ面に蜂
• pain in the neck    いやなこと
• referred pain    関連痛

العربيه (Arabic)
‏(الاسم) ألم, وجع, آلام الولادة والطلق (فعل) يؤلم, يوجع‏

עברית (Hebrew)
n. - ‮כאב, סבל, צער, צירי-לידה, מאמצים, טרחה, עונש‬
v. tr. - ‮ציער, גרם סבל, הכאיב‬
v. intr. - ‮הכאיב, סבל כאב‬

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t pain	Back Pain
Arthritis Pain	machine a pain