fever

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More about Fever: Causes and symptoms Diagnosis Treatment Prognosis Resources

Definition

A fever is any body temperature elevation over 100°F (37.8°C).

Description

A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat, which in turn activates different physical responses designed to

cool or warm the body, depending on the circumstances. These responses include: decreasing or increasing the flow of blood from the body's core, where it is warmed, to the surface, where it is cooled; slowing down or speeding up the rate at which the body turns food into energy (metabolic rate); inducing shivering, which generates heat through muscle contraction; and inducing sweating, which cools the body through evaporation.

A fever occurs when the thermostat resets at a higher temperature, primarily in response to an infection. To reach the higher temperature, the body moves blood to the warmer interior, increases the metabolic rate, and induces shivering. The "chills" that often accompany a fever are caused by the movement of blood to the body's core, leaving the surface and extremities cold. Once the higher temperature is achieved, the shivering and chills stop. When the infection has been overcome or drugs such as aspirin or acetaminophen (Tylenol) have been taken, the thermostat resets to normal and the body's cooling mechanisms switch on: the blood moves to the surface and sweating occurs.

Fever is an important component of the immune response, though its role is not completely understood. Physicians believe that an elevated body temperature has several effects. The immune system chemicals that react with the fever-inducing agent and trigger the resetting of the thermostat also increase the production of cells that fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, while at the same time speeding up the chemical reactions that help the body's cells repair themselves. In addition, the increased heart rate that may accompany the changes in blood circulation also speeds the arrival of white blood cells to the sites of infection.

— Bridget Travers

1. 1. Abnormally high body temperature.
   2. Any of various diseases characterized by abnormally high body temperature.
2. 1. A condition of heightened activity or excitement: a fever of anticipation.
   2. A contagious, usually short-lived enthusiasm or craze: disco fever.

To effect fever in.

To be or become feverish.

[Middle English, from Old English fefor and from Old French fievre, both from Latin febris.]

Key Terms: Acetaminophen, Antibiotic, Antihistamine, Biofeedback, Immune response, Neutropenia.

Description

Normal body temperature varies somewhat from one individual to another but displays a general range and pattern around the "normal" temperature of 98.6°F. Early morning body temperature may be as low as 97°F, and as high as 99.3°F in the afternoon hours yet still be considered normal. Higher temperatures may be observed in healthy people, but an abnormal elevation (pyrexia) is classified as hyperthermia, or fever. Fever results from a failure in the body's ability to regulate and dissipate heat. Any fever presents an unpleasant and uncomfortable state for the patient. Fever may cause the patient to experience fatigue, chills, sweats, nausea, and—in some cases—life-threatening conditions. When fevers occur in the elderly or the very young, the effects can be more harmful than in individuals who fall between those two age groups. The elderly may experience poor blood circulation, heart failure, an irregular heartbeat, or mental episodes. Children may lapse into fever-induced seizures. It is possible to treat fever with lukewarm sponge baths or bathing, removing excess clothing or bedding, and increasing the patient's fluid intake; however an important treatment is medication that lowers the body temperature to its normal range.

Causes

Fever associated with cancer can generally be categorized into four major causal groups: infection, tumors, allergic reactions to a drug, or allergic reaction to blood components in transfusion therapies. For cancer patients, fever should be considered a result of infection until an alternative cause is diagnosed. When a fever develops in a cancer patient, the individual must be thoroughly examined to determine the cause. A comprehensive physical examination should be administered by the physician and blood drawn for laboratory analysis.

Once a diagnosis has been made and treatment initiated, it is important to address problems created by the fever itself. It may be necessary to increase fluids and nutritional supplements. Because fever places increased demands on the body, this can be critical in restoring normal health for patients who may already be nutritionally compromised. Fever in a patient with neutropenia (low white blood cell count) represents the potential for a critical, life-threatening situation, and treatment should begin as quickly as the patient can reach the emergency room.

Physicians do not fully understand how tumors can cause fever, but certain correlations are well documented. Fever spikes may indicate that a tumor has grown or spread to other areas of the body, or that the tumor has produced some type of blockage. The fever associated with a tumor tends to be cyclic, and subsides with tumor treatment and recurs when the tumor returns or increases in size. In the case of drug-associated fever, the fever is an allergic-type reaction to a particular medication or combination of medications. Similarly, an immune response to donor blood cells is the typical cause of fever associated with blood components.

Treatments

Each of the major causes for fever associated with cancer has recommended conventional treatment procedures. For infection-related fever, broad-spectrum anti-biotics, given orally, rectally, or intravenously, are the principle method of control. Some antibiotics may be started before a definitive diagnosis is made to retard additional complications caused by the infection. Treatment typically is administered for five to seven days as long as the fever and infection show a positive response.

Fever from a tumor is best treated by treating the tumor itself. Supplemental treatment for the fever may include the use of nonsteroidal anti-inflammatory drugs (NSAIDs) and acetaminophen. Aspirin should only be used in patients with no risk of bleeding problems. The allergic responses manifesting in drug- or blood-associated fever may be treated by various methods: antihistamines and acetaminophen may be administered prior to drug therapy or blood transfusion therapy; discontinuing the present drug and choosing alternate medication may be required; blood may require irradiation or removal of white blood cells from the donor blood.

Alternative and Complementary Therapies

Some patients are investigating and adhering to the use of alternative treatments and complementary therapies. These choices may include holistic healing or herbal medication, and therapy utilizing biofeedback, relaxation therapy, and imagery techniques. Patients maintain that these alternative and complementary therapies add a sense of control to their life during a period when they have little control over anything. No conclusive data exists on the effectiveness of the therapies used alone; however in conjunction with conventional methods of fever management, they do not appear to hinder therapy and may provide the patient increased goodwill and a positive outlook.

Resources

Periodicals

Kern, Winfried., et al. "Oral versus Intravenous Empirical Antimicrobial Therapy for Fever in Patients with Granulocytopenia Who Are Receiving Cancer Chemotherapy." The New England Journal of Medicine 341, no. 5 (July 29, 1999): 312-318.

Other

Herbs for Relieving Cancer. InnerSelf 2000 Copyright. [cited April 21, 2001 and July 1, 2001]. .

—Jane Taylor-Jones, M.S.

An elevation in the central body temperature of warm-blooded animals caused by abnormal functioning of the thermoregulatory mechanisms. Fever accompanies a wide variety of disease states, both infectious and noninfectious, and in the great majority of instances is due to an abnormality in the regulation of body temperature by the central nervous system.

Experimental studies on the cause of fever suggest that leukocytes, as well as the fixed macrophages can be activated by various stimuli to produce a fever-inducing substance—endogenous pyrogen (EP). Endogenous pyrogen has been characterized as a protein of relatively low molecular weight (13,000) with an essential lipid moiety.

The mechanisms responsible for elevating body temperature include: reduction in heat loss by constriction of peripheral vessels whose tone is under control of the sympathetic nervous system; inhibition of panting and sweating, the latter by way of the cholinergic nerves; and increased heat production by means of shivering in voluntary muscles innervated by somatic motor nerves.

There is no clear evidence that elevated body temperature evoked by most infections is directly injurious to microbial invaders. As fever regularly accompanies inflammation, however, increased body temperature may well accelerate certain biochemical reactions of use to the host in combating infection. See also Homeostasis; Inflammation.

Fever a term derived from the Latin febris, refers to an elevation of body temperature due to disease or injury. Man is a homeotherm, meaning that body temperature is kept within narrow limits by complex control mechanisms. This is distinct from poikilotherms, such as reptiles and amphibians, whose body temperature is just above the ambient temperature, and varies with it. Measured in the mouth, body temperature is close to 37°C (98.6°F), and does not usually vary by more than 1.5°C, although a rise up to 40°C can occur transiently in strenuous muscular exercise. In excessive heat exposure, normal temperature regulation is defeated, resulting in heat stroke. In other circumstances any deviation from the norm in an upward direction constitutes fever. Fever, or pyrexia, refers to a rise of up to 40.5°C and hyperpyrexia to a greater rise. Above about 41.5°C a person loses orientation and may become unconscious.

In some diseases the word ‘fever’ is incorporated into the common names, such as in puerperal, scarlet, typhoid, and yellow fevers, indicating that a rise in termperature is associated with the condition. Before the advent of mass vaccination programmes those with infectious fevers were taken in to isolation hospitals, often called fever hospitals. The word ‘fever’ is sometimes used in other contexts, such as ‘fever pitch’, when an individual, group, or crowd (such as a football crowd) becomes over-excited or agitated.

The body has a complex mechanism for controlling temperature that balances heat production against heat loss. Heat is continually produced by metabolism of all body cells, to an extent that varies with the activity of glands and organs, and of the muscles (shivering is an effective way to increase heat production). Heat is lost by radiation and convection, particularly from exposed parts such as the face and hands, and by evaporation of sweat. The control of the balance between heat production and heat loss is centred in the brain, in the hypothalamus, which acts basically as a thermostat. Input signals from heat- and cold-sensitive receptors in the skin relay information to the hypothalamus (these receptors are extremely sensitive: the heat receptors are able to detect a rapid rise in temperature of 0.007°C, while the cold receptors can detect a rapid fall of 0.012°C) and the ‘thermostat’ also senses the temperature of the blood passing through. While the discomfort of the experience of hot and cold environments resides in the skin, it is the body's ‘core’ temperature that matters, as many processes within the body are disrupted if the core temperature changes. Thus if the blood temperature rises, then the output signals from the thermostat lead to vasodilation of blood vessels in the skin and to sweating, thus increasing heat loss. Or, if body temperature falls, then heat loss is curtailed by vasoconstriction of surface blood vessels, and heat production may be increased by shivering.

In fever the hypothalamic thermostat becomes set at a higher temperature. The normal blood temperature is therefore sensed as being too low, and temperature-raising mechanisms come into action, accounting for initial pallor and shivering. Conversely, when fever is abating the set temperature is lowered, and the warm skin and sweating represent heat loss mechanisms.

The commonest cause of fever is infection by viruses, bacteria, yeasts, or parasites. Substances are released by these organisms which are collectively called pyrogens (substances causing a rise in temperature — pyrexia). The pyrogens act upon white blood cells to produce further, endogenous, pyrogens; these latter can also be released from tumours, from the brain after injury or stroke, from blood clots, or in autoimmune disease. The endogenous pyrogens interact in the brain with prostaglandin synthetase, the enzyme necessary for synthesis of prostaglandins, which in turn are the main agents that alter the setting of the ‘thermostat’. This explains why taking aspirin can abolish fever, since it inhibits prostaglandin synthetase; it also explains why, in the absence of fever, aspirin has no effect on body temperature.

In general, it is the practice to use drugs to reduce fever, but this may reduce the effectiveness of macrophages (white cells) to engulf and destroy bacteria. Experimental evidence indicates that prevention of pyrexia is detrimental to survival in infected animals. It is equivocal whether or not fever can be universally regarded as a body defence mechanism, particularly as its usefulness or otherwise where there is no infection is obscure.

— Alan W. Cuthbert

See also heat exposure; injury; prostaglandins; temperature regulation.

A condition in which the body core temperature is higher than normal (oral temperature more than 37°C). Fever is usually caused by an infection that disturbs the temperature control centre in the brain, but it is sometimes linked to an emotional disturbance. It is often accompanied by headaches, shivering, and nausea. It can result in dehydration if sufficient liquids are not taken.

One golden rule of exercise is that you should avoid physical exertion during a fever which raises the core temperature above 38°C. The fever not only diminishes muscle strength and endurance, but it also increases the risk of heat exhaustion during exercise. More seriously, exercising during fevers may lead to inflammation of the heart (myocarditis). Although this may be very rare, myocarditis is a potentially fatal condition.

Definition: state of high temperature or agitation
Antonyms: chill, coldness, freeze, frigidity

Definition

A fever is a rise in body temperature to greater than 100°F (37.8°C).

Description

A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat. In turn, the thermostat activates different physical responses designed to cool or warm the body, depending on the circumstances. These responses include:

• decreasing or increasing the flow of blood from the body's core, where it is warmed, to the surface, where it is cooled
• slowing down or speeding up the rate at which the body turns food into energy (metabolic rate)
• inducing shivering, which generates heat through muscle contraction
• inducing sweating, which cools the body through evaporation

A fever occurs when the body's thermostat resets at a higher temperature, which primarily happens in response to an infection. To reach the higher temperature, the body moves blood to the warmer interior, increases the metabolic rate, and induces shivering. The chills that often accompany a fever are caused by the movement of blood to the body's core, which leaves the surface and extremities cold. Once the body reaches the higher temperature, the shivering and chills stop. When the infection has been overcome or drugs such as aspirin or acetaminophen (Tylenol) have been taken, the thermostat resets to normal. When this happens, the body's cooling mechanisms switch on. The blood moves to the surface and sweating occurs.

Fever is an important component of the immune response, though its role is not completely understood. Physicians believe that an elevated body temperature has several effects. Certain chemicals in the immune system react with the fever-inducing agent and trigger the resetting of the thermostat. These immune system chemicals also increase the production of cells that fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria and speed up the chemical reactions that help the body's cells repair themselves. Changes in blood circulation may cause the heart rate to increase, which speeds the arrival of white blood cells to the sites of infection.

Causes & Symptoms

Fevers are primarily caused by viral or bacterial infections, such as pneumonia or influenza. However, other conditions can induce a fever, including these:

• allergic reactions
• autoimmune diseases
• trauma, such as breaking a bone
• cancer
• excessive exposure to the sun
• intense exercise
• hormonal imbalances
• certain drugs
• damage to the hypothalamus

When an infection occurs, fever-inducing agents called pyrogens are released, either by the body's immune system or by the invading cells themselves. These pyrogens trigger the resetting of the thermostat. In other circumstances, an uncontrolled release of pyrogens may occur when the immune system overreacts due to an allergic reaction or becomes damaged due to an autoimmune disease. A stroke or tumor can damage the hypothalamus, causing the body's thermostat to malfunction. Excessive exposure to the sun or intense exercise in hot weather can result in heat stroke, a condition in which the body's cooling mechanisms fail. Malignant hyperthermia is a rare, inherited condition in which a person develops a very high fever when given certain anesthetics or muscle relaxants in preparation for surgery.

A recent study showed that most parents have misconceptions about fever and view it as a disease rather than a symptom. How long a fever lasts and how high it may go depend on several factors, including its cause and the patient's age and overall health. Most fevers caused by infections are acute, appearing suddenly and then dissipating as the immune system defeats the infectious agent. An infectious fever may also rise and fall throughout the day, reaching its peak in the late afternoon or early evening. A low-grade fever that lasts for several weeks is associated with autoimmune diseases such as lupus or with some cancers, particularly leukemia and lymphoma.

Diagnosis

A fever is usually diagnosed using a thermometer. A variety of different thermometers are available, including traditional oral and rectal thermometers made of glass and mercury, and more sophisticated electronic ones that can be inserted in the ear. For adults and older children, temperature readings are usually taken orally. Younger children who cannot or will not hold a thermometer in their mouths can have their temperatures taken by placing an oral thermometer under their armpits. Infants generally have their temperature taken rectally using a rectal thermometer.

As important as registering a patient's temperature is determining the underlying cause of the fever. The physician can make a diagnosis by checking for accompanying symptoms and by reviewing the patient's medical history, any recent trips he or she has taken, what he or she may have ingested, or any illnesses he or she has been exposed to. Blood tests hold additional clues. Anti-bodies in the blood point to the presence of an infectious agent, which can be verified by growing the organism in a culture. Blood tests can also provide the doctor with white blood cell counts. Ultrasound tests, magnetic resonance imaging (MRI) tests, or computed tomography (CT) scans may be ordered if the doctor cannot readily determine the cause of a fever.

Treatment

Often, doctors must remind patients, especially parents, not to "overtreat" low fevers but to remember that they are symptoms of an underlying disease or condition. Alternative therapies for treatment of fever focus not only on reducing fever but also on boosting the immune function to help the body fight infections more effectively. They include nutritional therapy, herbal therapy and traditional Chinese medicine.

Nutritional Therapy

Naturopaths often recommend that patients take high doses of vitamin C to ward off diseases and prevent fever. In addition to vitamin C, other antioxidants such as vitamin A and zinc also boost the immune function. Naturopaths may also suggest reducing sugar intake (even fruit juices) because sugar depresses the immune system. To replace fluid that is lost during fever, patients are advised to drink vegetable juices and eat soups.

Herbal Therapy

Western herbalists use tea preparations containing herbs such as bupleurum root or boneset to reduce fever. Mild herbs such as peppermint, elderflower, or yarrow can provide comfort to the child who has a mild fever. Others believe in sweating a fever out, literally. They often recommend that patients take hot baths to induce sweating. This helps induce or increase fever, which is believed to help the body get rid of infections.

Chinese medicine (TCM) offers many herbs and formulas for fevers. There are many distinct kinds of fevers, also called heat syndromes. For example, an excess-heat syndrome is characterized by a high fever, great thirst, and lots of sweating. Deficiency heat syndrome is characterized by a low-grade fever with afternoon fevers or night sweats. For excess heat, herbs that are dispersing and cold in nature are used. For chronic and low-grade fevers, herbs that tonify the yin (cooling aspect) are used as well as herbs that get rid of heat. There are even herbs such as bupleurum root (called Chai Hu in TCM) that are used for intermittent fevers or conditions alternating between fever and chills. Alternating fevers and chills occur in malaria, conditions connected to AIDS, chronic fatigue syndrome, and Epstein-Barr virus. The individual pattern should be diagnosed by a trained practitioner.

Aromatherapy

Patients can reduce feverish symptoms by inhaling essential oils of camphor, eucalyptus, lemon, and hyssop. These oils can also be mixed with an unscented body lotion or a vegetable oil for aromatherapy massage.

Homeopathy

Homeopathic doctors may prescribe herbal remedies based on the patient's overall personality profile as well as specific symptoms.

Allopathic Treatment

Physicians agree that the most effective treatment for a fever is to address its underlying cause. Also, because a fever helps the immune system fight infection, some clinicians suggest it be allowed to run its course. Drugs to lower fever (antipyretics) can be given if a patient (particularly a child) is uncomfortable. These include aspirin, acetaminophen (Tylenol), and ibuprofen (Advil). Aspirin, however, should not be given to a child or adolescent with a fever since this drug has been linked to an increased risk of Reye's syndrome. Sponging a child or infant with tepid (lukewarm) water can also help reduce mild fevers.

A fever requires emergency treatment under the following circumstances:

• Newborn (three months or younger) with a fever above 100.5°F (38°C).
• Infant or child with a fever above 103°F (39.4°C). A very high fever in a small child can trigger seizures (febrile seizures) and therefore should be treated immediately.
• Fever accompanied by severe headache, neck stiffness, mental confusion, or severe swelling of the throat. A fever accompanied by these symptoms can indicate the presence of a serious infection, such as meningitis, and should be brought to the immediate attention of a physician.

Expected Results

Most fevers caused by infection end as soon as the immune system rids the body of the pathogen. Most fevers do not produce any lasting effects. The prognosis for fevers associated with more chronic conditions, such as autoimmune disease, depends upon the overall outcome of the disorder.

Resources

Books

Bennett, J. Claude, and Fred Plum, eds. Cecil Textbook of Medicine. Philadelphia: W. B. Saunders, 1996.

"Children's Health." In Alternative Medicine: The Definitive Guide, compiled by The Burton Goldberg Group. Tiburon, CA: Future Medicine Publishing, 1999.

"Fever and Chills." In Reader's Digest Guide to Medical Cures and Treatment. New York: Reader's Digest Association, 1996.

Gelfand, Jeffrey, et al. "Fever, Including Fever of Unknow Origin." In Harrison's Principles of Internal Medicine, edited by Kurt Isselbacher, et al. New York: McGraw-Hill, 1997.

Tierney, Lawrence M., M.D., et al., eds. Current Medical Diagnosis and Treatment. Stamford, CT: Appleton & Lange, 1996.

Periodicals

Bernath, Vivienne F."Tepid Sponging and Paracetamol for Reduction of Body Temperature in Febrile Children." The Medical Journal of Australia (February 4, 2002):130.

Huffman, Grace B. "Parental Misconceptions about Fever in Children." American Family Physician (February 1, 2002):482.

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

Definition

A fever is any body temperature elevation over 100.4°F (38°C).

Description

A healthy person's body temperature fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). The body maintains stability within this range by balancing the heat produced by the metabolism with the heat lost to the environment. The "thermostat" that controls this process is located in the hypothalamus, a small structure located deep within the brain. The nervous system constantly relays information about the body's temperature to the thermostat, which in turn activates different physical responses designed to cool or warm the body, depending on the circumstances. These responses include: decreasing or increasing the flow of blood from the body's core, where it is warmed, to the surface, where it is cooled; slowing down or speeding up the rate at which the body turns food into energy (metabolic rate); inducing shivering, which generates heat through muscle contraction; and inducing sweating, which cools the body through evaporation.

A fever occurs when the thermostat resets at a higher temperature, primarily in response to an infection. To reach the higher temperature, the body moves blood to the warmer interior, increases the metabolic rate, and induces shivering. The chills that often accompany a fever are caused by the movement of blood to the body's core, leaving the surface and extremities cold. Once the higher temperature is achieved, the shivering and chills stop. When the infection has been overcome or drugs such as aspirin or acetaminophen have been taken, the thermostat resets to normal and the body's cooling mechanisms switch on: the blood moves to the surface and sweating occurs.

Fever is an important component of the immune response, though its role is not completely understood. Physicians believe that an elevated body temperature has several effects. The immune system chemicals that react with the fever-inducing agent and trigger the resetting of the thermostat also increase the production of cells that fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, while at the same time speeding up the chemical reactions that help the body's cells repair themselves. In addition, the increased heart rate that may accompany the changes in blood circulation also speeds the arrival of white blood cells to the sites of infection.

Demographics

Fevers are components of many disease entities. Virtually all persons experience fevers at some time in their lives. Elevations in temperature are not reportable events. Thus, accurate data regarding the prevalence of fevers are not available.

Causes and Symptoms

Fevers are primarily caused by viral or bacterial infections, such as pneumonia or influenza. However, other conditions can induce a fever, including allergic reactions; autoimmune diseases; trauma, such as breaking a bone; cancer; excessive exposure to the sun; intense exercise; hormonal imbalances; certain drugs; and damage to the hypothalamus. When an infection occurs, fever-inducing agents called pyrogens are released, either by the body's immune system or by the invading cells themselves that trigger the resetting of the thermostat. In other circumstances, the immune system may overreact (allergic reactions) or become damaged (autoimmune diseases), causing the uncontrolled release of pyrogens. A stroke or tumor can damage the hypothalamus, causing the body's thermostat to malfunction. Excessive exposure to the sun or intense exercise in hot weather can result in heat stroke, a condition in which the body's cooling mechanisms fail. Malignant hyperthermia is a rare, inherited condition in which a person develops a very high fever when given certain anesthetics or muscle relaxants in preparation for surgery.

How long a fever lasts and how high it may go depends on several factors, including its cause, the age of the person, and his or her overall health. Most fevers caused by infections are acute, appearing suddenly and then dissipating as the immune system defeats the infectious agent. An infectious fever may also rise and fall throughout the day, reaching its peek in the late afternoon or early evening. A low-grade fever that lasts for several weeks is associated with autoimmune diseases such as lupus or with some cancers, particularly leukemia and lymphoma.

When to Call the Doctor

A doctor or other healthcare provider should be called when a fever does not resolve after two to three days. Anyone with a fever over 104°F (40.0°C) should seek immediate medical treatment.

A doctor should be called when an infant's temperature rises above 100°F (37.8°C) and cannot be brought down within a few minutes. Infants whose temperatures exceed 102°F (38.9°C) should be immersed in warm or tepid water to help reduce temperature slowly, while waiting for emergency help to arrive.

Diagnosis

A fever is usually diagnosed using a thermometer. A variety of different thermometers are available. Glass thermometer should not be used since they can break and release mercury, which is toxic. Digital thermometers can and should be used in place of glass thermometers rectally, orally, and under the arm in all age groups. Electronic thermometers can be inserted in the ear to quickly register the body's temperature.

As important as registering a person's temperature is determining the underlying cause of the fever. The presence or absence of accompanying symptoms, a person's medical history, and information about what he or she may have ingested, any recent trips taken, or possible exposures to illness all help the physician make a diagnosis. Blood tests can aid in identifying an infectious agent by detecting the presence of antibodies against it or providing samples for growth of the organism in a culture. Blood tests can provide the doctor with white blood cell counts. Ultrasound tests, magnetic resonance imaging (MRI) tests, or computed tomography (CT) scans may be ordered if the doctor cannot readily determine the cause of a fever.

Treatment

Physicians agree that the most effective treatment for a fever is to address its underlying cause, such as through the administration of antibiotics. Also, because a fever helps the immune system fight infection, it usually should be allowed to run its course. Drugs to lower fever (antipyretics) can be given if a person (particularly a child) is uncomfortable. These include acetaminophen and ibuprofen. Aspirin, however, should not be given to a child or adolescent with a fever since this drug has been linked to an increased risk of Reye's syndrome. Bathing a person in tepid water can also help alleviate a high fever.

A fever requires emergency treatment under the following circumstances:

• newborn (three months or younger) with a fever over 100.5°F (38°C)
• infant or child with a fever over 103°F (39.4°C)
• fever accompanied by severe headache, neck stiffness, mental confusion, or severe swelling of the throat

A very high fever in a small child can trigger seizures (febrile seizures) and, therefore, should be treated immediately. A fever accompanied by the above symptoms can indicate the presence of a serious infection, such as meningitis, and should be brought to the immediate attention of a physician.

Prognosis

Most fevers caused by infection end as soon as the immune system rids the body of the pathogen, and these fevers do not produce lasting effects. The prognosis for fevers associated with more chronic conditions, such as autoimmune disease, depends upon the overall outcome of the disorder.

Prevention

Fevers may be prevented by avoiding the various diseases that cause them.

Nutritional Concerns

Adequate nutrition via a well-balanced diet and sufficient intake of liquid help to reduce many fevers. Adequate intake of electrolytes such as sodium, chloride, potassium, phosphate, and bicarbonate helps to prevent dehydration that often accompanies a fever.

Parental Concerns

Parents should carefully monitor their infants and young children for symptoms of fever. Any fever that exceeds 103°F (39.4°C) for more than a few minutes should be promptly treated.

Resources

Books

Barlam, Tamar F., and Dennis L. Kasper. "Approach to the Acutely Ill Infected Febrile Patient." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 95–101.

Beutler, Bruce, and Steven M. Beutler. "The Pathogenesis of Fever." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1730–32.

Bisno, Alan L. "Rheumatic Fever." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1788–93.

Dale, David C. "The Febrile Patient." In Cecil Textbook of Medicine, 22nd ed. Edited by Lee Goldman et al. Philadelphia: Saunders, 2003, pp. 1729–30.

Dinarello, Charles A., and Jeffrey A. Gelfand. "Fever and Hyperthermia." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 91–4.

Dumler, J. Stephen. "Q Fever (Coxiella burnetii)." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 1009–10.

——. "Spotted Fever Group Rickettsioses." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 999–1003.

Halstead, Scott B. "Yellow Fever." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 1095–6.

——. "Dengue Fever and Dengue Hemorrhagic Fever." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 1092–4.

Kaye, Elaine T., and Kenneth M. Kaye. "Fever and Rash." In Harrison's Principles of Internal Medicine, 15th ed. Edited by Eugene Braunwald et al. New York: McGraw-Hill, 2001, pp. 95–101.

Powell, Keith R. "Fever without a Focus." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 841–5.

——. "Fever." In Nelson Textbook of Pediatrics, 17th ed. Edited by Richard E. Behrman et al. Philadelphia: Saunders, 2003, pp. 839–40.

Periodicals

Dinarello, C. A. "Infection, fever, and exogenous and endogenous pyrogens: some concepts have changed." Journal of Endotoxin Research 10, no. 4 (2004): 201–22.

Galache, C., et al. "Q fever: a new cause of 'doughnut' granulomatous lobular panniculitis." British Journal of Dermatology 151, no. 3 (2004): 685–7.

Huang, S. Y., et al. "Effect of Recent Antipyretic Use on Measured Fever in the Pediatric Emergency Department." Archives of Pediatric and Adolescent Medicone 158, no. 10 (2004): 972–6.

Organizations

American Academy of Emergency Medicine. 611 East Wells St., Milwaukee, WI 53202. Web site: www.aaem.org/.

American Academy of Pediatrics. 141 Northwest Point Boulevard, Elk Grove Village, IL 60007–1098. Web site: www.aap.org/.

American Association of Naturopathic Physicians. 8201 Greensboro Drive, Suite 300, McLean, VA 22102. Web site: .

American Society of Clinical Pathologists. 2100 West Harrison Street, Chicago IL 60612. Web site: www.ascp.org/index.asp.

College of American Pathologists. 325 Waukegan Road, Northfield, IL 60093. Web site: www.cap.org/.

Meningitis Foundation of America Inc. 7155 Shadeland Station, Suite 190, Indianapolis, IN 46256–3922. Web site: www.musa.org/default.htm.

Web Sites

"Fever." MedlinePlus. Available online at www.nlm.nih.gov/medlineplus/ency/article/003090.htm (accessed January 6, 2005).

"Typhoid Fever." Centers for Disease Control and Prevention. Available online at www.cdc.gov/ncidod/dbmd/diseaseinfo/typhoidfever_g.htm (accessed January 6, 2005).

"Yellow Fever." Centers for Disease Control and Prevention. Available online at www.cdc.gov/travel/diseases/yellowfever.htm (accessed January 6, 2005).

"Yellow Fever." World Health Organization. Available online at www.who.int/csr/disease/yellowfev/en/ (accessed January 6, 2005).

[Article by: L. Fleming Fallon Jr., MD, DrPH]

For more information on fever, visit Britannica.com.

A condition in which the core temperature is higher than normal (i.e. oral temperature more than 37 °C and rectal temperature more than 37.2 °C). Fever is usually due to an infection, but may also he linked to an emotional condition. It is usually accompanied by headaches, shivering, and nausea. Fever is caused by a rise in the set point in the temperature control centre in the hypothalamus, so that heat-loss mechanisms (e.g. sweating) do not begin until core temperature exceeds that of the new set point. Fever can result in dehydration and loss of muscle strength. Exercise during some febrile diseases can worsen the illness. This applies especially to enteroviral infections. It is a golden rule of sports medicine that an athlete should not compete or take part in strenuous physical activity when in a fever which raises body core temperature above 38 °C.

1. an abnormally high body temperature; pyrexia. See also hyperthermia.
2. any disease characterized by marked increase of body temperature. See body temperature.
For diseases characterized by fever, see the eponymic or descriptive name: e.g. african swine, bovine petechial, canicola, cat-scratch disease, desert, ephemeral, equine intestinal ehrlichiosis, classical swine fever (hog cholera), malignant catarrhal fever, malta, mediterranean coast, q, rift valley, rocky mountain spotted, Russian spring–summer encephalitis, tickborne, tularemia, undulant. milk fever is not accompanied by pyrexia.

• aseptic f. — fever associated with aseptic wounds, presumably due to the disintegration of leukocytes or to the absorption of avascular or traumatized tissue.
• central f. — sustained fever resulting from damage to the thermoregulatory centers of the hypothalamus.
• chemical f. — fever caused by the intake of a sterile substance, e.g. the injection of a foreign protein, the administration of dinitrophenols.
• continued f., continuous f. — persistently elevated body temperature, showing no or little variation and never falling to normal during any 24-hour period.
• intermittent f. — an attack of fever, with recurring paroxysms of elevated temperature separated by intervals during which the temperature is normal.
• remittent f. — elevated body temperature showing fluctuation each day, but never falling to normal.
• septic f. — see septic fever.
• Shar Pei f. — see familial renal amyloidosis.
• f. of unknown origin (FUO) — a recognized clinical syndrome of persistently (>2 weeks) elevated body temperature (>104°F) and without other signs. Causes include infections, neoplasia, immune-mediated diseases, and drug reactions.

It has been suggested that Hyperpyrexia be merged into this article or section. (Discuss)

This article is about the medical condition. For other uses, see Fever (disambiguation).

Fever

An analog medical thermometer showing the temperature of 38.7 °C
ICD-10	R50.
ICD-9	780.6
DiseasesDB	18924
eMedicine	med/785
MeSH	D005334

Fever (also known as pyrexia, from the Greek pyretos meaning fire, or a febrile response, from the Latin word febris, meaning fever, and archaically known as ague) is a frequent medical sign that describes an increase in internal body temperature to levels above normal. Fever is most accurately characterized as a temporary elevation in the body's thermoregulatory set-point, usually by about 1–2 °C (1.8-3.6 °F).

Fever is caused by an elevation in the thermoregulatory set-point, causing typical body temperature (generally and problematically considered to be 37 °C or 98.6 °F; see below for specifics) to rise, and effector mechanisms are enacted as a result. A feverish individual has a general feeling of cold despite an increased body temperature, and increases in heart rate, muscle tone and shivering, all of which are caused by the body's attempts to counteract the newly-perceived hypothermia and reach the new thermoregulatory set-point.

Fever differs from hyperthermia in that hyperthermia is an increase in body temperature over the body's thermoregulatory set-point, due to excessive heat production or insufficient thermoregulation, or both.

A fever is considered one of the body's immune mechanisms to attempt a neutralization of a perceived threat inside the body, be it bacterial or viral. Carl Wunderlich discovered that fever is not a disease, but the body's response to a disease.

Contents 1 Measurement and normal variation 2 Mechanism 2.1 Pyrogens 2.1.1 Endogenous 2.1.2 Exogenous 2.2 PGE2 release 2.3 Hypothalamus response 3 Types 4 Causes 5 Usefulness of fever 6 Treatment 7 Fever in domestic animals 8 Diseases called "fever" 8.1 In humans 8.2 In animals 9 References 10 Further reading 11 External links

Measurement and normal variation

When a patient has or is suspected of having a fever, that person's body temperature is measured using a thermometer. At a first glance, fever is present if:^{[citation needed]}

• Temperature in the anus (rectum/rectal) is at or over 37.8 °C (100.0 °F)
• Temperature in the mouth (oral) is at or over 37.5 °C (99.5 °F)
• Temperature under the arm (axillary) is at or over 37.2 °C (99.0 °F)
• Temperature in the ear (otic) is at or over 37.2 ºC (99.0 ºF)

The common oral measurement of normal human body temperature is 36.8±0.7 °C (98.2±1.3 °F). This means that any oral temperature between 36.1 and 37.5 °C (96.9 and 99.5 °F) is likely to be normal.

However, there are many variations in normal body temperature, and this needs to be considered when measuring for fever. The values given are for an otherwise healthy, non-fasting adult, dressed comfortably, indoors, in a room that is kept at a normal room temperature (22.7 to 24.4 °C or 73 to 76 °F), during the morning, but not shortly after arising from sleep. Furthermore, for oral temperatures, the subject must not have eaten, drunk, or smoked anything in at least the previous fifteen to twenty minutes.

Body temperature normally fluctuates over the day, with the lowest levels around 4 a.m. and the highest around 6 p.m.^[1] (assuming the subject follows the prevalent pattern, i.e., sleeping at nighttime and staying awake during daytime). Therefore, an oral temperature of 37.2 °C (99.0 °F) would strictly be a fever in the morning, but not in the afternoon. An oral body temperature reading up to 37.5 °C (99.5 °F) in the early/late afternoon or early/late evening also wouldn't be a fever. Normal body temperature may differ as much as 1 °F (0.6 °C) between individuals or from day to day. In women, temperature differs at various points in the menstrual cycle, and this can be used as part of fertility awareness (although temperature is only one of the variables). Temperature is increased after eating, and psychological factors also influence body temperature.

There are different locations where temperature can be measured, and these differ in temperature variability. Tympanic membrane thermometers measure radiant heat energy from the tympanic membrane (infrared). These may be very convenient, but may also show more variability.

Children develop higher temperatures with activities like playing, but this is not fever because their set-point is normal. Elderly patients may have a decreased ability to generate body heat during a fever, so even a low-grade fever can have serious underlying causes in geriatrics.

Fever is usually accompanied by sickness behavior which consists of lethargy, depression, anorexia, sleepiness, hyperalgesia, and the inability to concentrate.^[2][3][4]

Mechanism

Temperature is ultimately regulated in the hypothalamus. A trigger of the fever, called a pyrogen, causes a release of prostaglandin E2 (PGE2). PGE2 then in turn acts on the hypothalamus, which generates a systemic response back to the rest of the body, causing heat-creating effects to match a new temperature level.

Hyperthermia: Characterized on the left. Normal body temperature (thermoregulatory set-point) is shown in green, while the hyperthermic temperature is shown in red. As can be seen, hyperthermia can be conceptualized as an increase above the thermoregulatory set-point.
Hypothermia: Characterized in the center: Normal body temperature is shown in green, while the hypothermic temperature is shown in blue. As can be seen, hypothermia can be conceptualized as a decrease below the thermoregulatory set-point.
Fever: Characterized on the right: Normal body temperature is shown in green. It reads "New Normal" because the thermoregulatory set-point has risen. This has caused what was the normal body temperature (in blue) to be considered hypothermic.

Pyrogens

A pyrogen is a substance that induces fever. These can be either internal (endogenous) or external (exogenous) to the body. The bacterial substance lipopolysaccharide (LPS), present in the cell wall of some bacteria, is an example of an exogenous pyrogen. Pyrogenicity can vary, as in extreme examples some bacterial pyrogens known as superantigens can cause rapid and dangerous fevers. Depyrogenation may be achieved through filtration, distillation, chromatography, or inactivation.

Endogenous

Cytokines (especially interleukin 1) are a part of the innate immune system, are produced by phagocytic cells, and cause the increase in the thermoregulatory set-point in the hypothalamus. Other examples of endogenous pyrogens are interleukin 6 (IL-6), and tumor necrosis factor-alpha.

These cytokine factors are released into general circulation where they migrate to the circumventricular organs of the brain due to easier absorption caused by the blood-brain barrier's reduced filtration action there. The cytokine factors then bind with endothelial receptors on vessel walls, or interact with local microglial cells. When these cytokine factors bind, the arachidonic acid pathway is then activated.

Exogenous

One model for the mechanism of fever caused by exogenous pyrogens includes LPS, which is a cell wall component of gram-negative bacteria. An immunological protein called lipopolysaccharide-binding protein (LBP) binds to LPS. The LBP–LPS complex then binds to the CD14 receptor of a nearby macrophage. This binding results in the synthesis and release of various endogenous cytokine factors, such as interleukin 1 (IL-1), interleukin 6 (IL-6), and the tumor necrosis factor-alpha. In other words, exogenous factors cause release of endogenous factors, which, in turn, activate the arachidonic acid pathway.

PGE2 release

PGE2 release comes from the arachidonic acid pathway. This pathway (as it relates to fever), is mediated by the enzymes phospholipase A2 (PLA2), cyclooxygenase-2 (COX-2), and prostaglandin E2 synthase. These enzymes ultimately mediate the synthesis and release of PGE2.

PGE2 is the ultimate mediator of the febrile response. The set-point temperature of the body will remain elevated until PGE2 is no longer present. PGE2 acts on neurons in the preoptic area (POA) through the prostaglandin E receptor 3 (EP3). EP3-expressing neurons in the POA innervate the dorsomedial hypothalamus (DMH), the rostral raphe pallidus nucleus in the medulla oblongata (rRPa) and the paraventricular nucleus (PVN) of the hypothalamus . Fever signals sent to the DMH and rRPa lead to stimulation of the sympathetic output system, which evokes non-shivering thermogenesis to produce body heat and skin vasoconstriction to decrease heat loss from the body surface. It is presumed that the innervation from the POA to the PVN mediates the neuroendocrine effects of fever through the pathway involving pituitary gland and various endocrine organs.

Hypothalamus response

The brain ultimately orchestrates heat effector mechanisms via the autonomic nervous system. These may be:

• Increased heat production by increased muscle tone, shivering and hormones like epinephrine.
• Prevention of heat loss, such as vasoconstriction.

The autonomic nervous system may also activate brown adipose tissue to produce heat (non-exercise-associated thermogenesis, also known as non-shivering thermogenesis), but this seems mostly important for babies. Increased heart rate and vasoconstriction contribute to increased blood pressure in fever.

Types

According to one common rule of thumb, fever is generally classified for convenience as an anal (core) temperature of:

Fever classification

Grade	°C	°F
low grade	38–39	100.4–102.2
moderate	39–40	102.2–104.0
high-grade	40–41.1	104.0–106.0
hyperpyrexia	>41.1	>106.0

The last is a medical emergency because it approaches the upper limit compatible with human life. If the temperature is taken by another route (mouth, ear, armpit), then the reading needs to be converted to the equivalent core body temperature.

Most of the time, fever types can not be used to find the underlying cause. However, there are specific fever patterns that may occasionally hint the diagnosis:

• Pel-Ebstein fever: A specific kind of fever associated with Hodgkin's lymphoma, being high for one week and low for the next week and so on. However, there is some debate as to whether this pattern truly exists.^[5]
• Continuous fever: Temperature remains above normal throughout the day and does not fluctuate more than 1 °C in 24 hours, e.g. lobar pneumonia, typhoid, urinary tract infection, brucellosis, or typhus. Typhoid fever may show a specific fever pattern, with a slow stepwise increase and a high plateau.
• Intermittent fever: Elevated temperature is present only for some hours of the day and becomes normal for remaining hours, e.g. malaria, kala-azar, pyaemia, or septicemia. In malaria, there may be a fever with a periodicity of 24 hours (quotidian), 48 hours (tertian fever), or 72 hours (quartan fever, indicating Plasmodium malariae). These patterns may be less clear in travelers.
• Remittant fever: Temperature remains above normal throughout the day and fluctuates more than 1 °C in 24 hours, e.g. infective endocarditis.

A neutropenic fever, also called febrile neutropenia, is a fever in the absence of normal immune system function. Because of the lack of infection-fighting neutrophils, a bacterial infection can spread rapidly and this fever is therefore usually considered a medical emergency. This kind of fever is more commonly seen in people receiving immune-suppressing chemotherapy than in apparently healthy people.

Febricula^[6] is a mild fever of short duration, of indefinite origin, and without any distinctive pathology.

Causes

Fever is a common symptom of many medical conditions:

• Infectious disease, e.g. influenza, HIV, malaria, infectious mononucleosis, or gastroenteritis
• Various skin inflammations, e.g. boils, pimples, acne, or abscess
• Immunological diseases, e.g. lupus erythematosus, sarcoidosis, inflammatory bowel diseases
• Tissue destruction, which can occur in hemolysis, surgery, infarction, crush syndrome, rhabdomyolysis, cerebral hemorrhage, etc.
• Drug fever
  • Directly caused by the drug, e.g. lamictal, progesterone, or chemotherapeutics causing tumor necrosis
  • As an adverse reaction to drugs, e.g. antibiotics or sulfa drugs.
  • After drug discontinuation, e.g. heroin or fentanyl withdrawal
• Reaction to incompatible blood products
• Cancers, most commonly renal cancer and leukemia and lymphomas
• Metabolic disorders, e.g. gout or porphyria
• Thrombo-embolic processes, e.g. pulmonary embolism or deep venous thrombosis

Persistent fever which cannot be explained after repeated routine clinical inquiries, is called fever of unknown origin.

Usefulness of fever

There are arguments for and against the usefulness of fever, and the issue is controversial.^[7][8] There are studies using warm-blooded vertebrates^[9] and humans^[10] in vivo, with some suggesting that they recover more rapidly from infections or critical illness due to fever. A Finnish study suggested reduced mortality in bacterial infections when fever was present.^[11]

Theoretically, fever can aid in host defense.^[7] There are certainly some important immunological reactions that are sped up by temperature, and some pathogens with strict temperature preferences could be hindered.^[12] Fevers may be useful to some extent since they allow the body to reach high temperatures, causing an unbearable environment for some pathogens. White blood cells also rapidly proliferate due to the suitable environment and can also help fight off the harmful pathogens and microbes that invaded the body.^{[citation needed]}

Research^[13] has demonstrated that fever has several important functions in the healing process:

• Increased mobility of leukocytes
• Enhanced leukocytes phagocytosis
• Endotoxin effects decreased
• Increased proliferation of T cells^[14]
• Enhanced activity of interferon^[14]

Treatment

This section does not cite any references or sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (March 2008)

Fever should not necessarily be treated. Fever is an important signal that there's something wrong in the body, and it can be used to govern medical treatment and gauge its effectiveness. Moreover, not all fevers are of infectious origin.

Even when treatment is not indicated, however, febrile patients are generally advised to keep themselves adequately hydrated, as the dehydration produced by a mild fever can be more dangerous than the fever itself. Water is generally used for this purpose, but there is always a small risk of hyponatremia if the patient drinks too much water. For this reason, some patients drink sports drinks or electrolyte-replacing products designed specifically for this purpose.

Most people take medication against fever because the symptoms cause discomfort. Fever increases heart rate and metabolism, thus potentially putting an additional strain on elderly patients, patients with heart disease, etc. This may even cause delirium. Therefore, potential benefits must be weighed against risks in these patients. In any case, fever must be brought under control in instances when fever escalates to hyperpyrexia and tissue damage is imminent.

Treatment of fever is normally done by lowering the set-point, but facilitating heat loss may also be effective. The former is accomplished with antipyretics such as ibuprofen or paracetamol (US acetominophen). Aspirin can also be given to adults, but can cause Reye's Syndrome in children. Heat removal is generally by wet cloth or pads, usually applied to the forehead,^[15] but also through bathing the body in tepid water. This is particularly important for babies, where drugs should be avoided. However, using water that is too cold can induce vasoconstriction, and reduce effective heat loss.

Heat loss may also be accomplished by heat conduction, convection, radiation, or evaporation (sweating, perspiration), or a combination of these.

Fever in domestic animals

Fever is also an important feature for the diagnosis of disease in domestic animals. The body temperature of animals, which is taken rectally, is different from one species to another. For example, a horse is said to have a fever at 38.5 °C, while a cow is said to have a fever at 39.6 °C.^{[citation needed]}

In species that allow the body to have a wide range of "normal" temperatures, such as camels, it is sometimes difficult to determine a febrile stage.

Diseases called "fever"

As fever is a prominent symptom of many diseases, in humans and animals, it will often appear in the common appellation of diseases.

In humans

• Puerperal fever
• Scarlet fever
• Typhoid fever
• Malaria, archaically fever and ague
• Viral hemorrhagic fever
  • Ebola fever
  • Dengue fever
  • Yellow fever

In animals

• East Coast fever (an African disease of cattle)
• Malignant catarrhal fever (a worldwide disease of cattle)
• Rift valley fever (an African disease of sheep)
• Classical and African swine fevers (diseases of pigs)

References

1. ^ Body Temperature
2. ^ Hart, B. L. (1988) "Biological basis of the behavior of sick animals". Neurosci Biobehav Rev. 12: 123-137.PubMed
3. ^ Johnson, R. (2002) "The concept of sickness behavior: a brief chronological account of four key discoveries". Veterinary Immunology and Immunopathology. 87: 443-450 PubMed
4. ^ Kelley, K. W., Bluthe, R. M., Dantzer, R., Zhou, J. H., Shen, W. H., Johnson, R. W. Broussard, S. R. (2003) "Cytokine-induced sickness behavior". Brain Behav Immun. 17 Suppl 1: S112-118 PubMed
5. ^ Hilson, A.J.W.; DiNubile, M.J. (1995-07-06), "Correspondence", New England Journal of Medicine 333: 66–67, doi:10.1056/NEJM199507063330118, PMID 7777006, http://content.nejm.org/cgi/content/short/333/1/66, retrieved on 2008-03-18 . They cite Richard Asher's lecture Making Sense (Lancet, 1959, 2, 359)
6. ^ Febricula, definition from Biology-Online.org, consulted June 7, 2006 http://www.biology-online.org/dictionary/Febricula
7. ^ ^{a b} Schaffner A. Fever—useful or noxious symptom that should be treated? Ther Umsch 2006; 63: 185-8. PMID 16613288
8. ^ Soszynski D. The pathogenesis and the adaptive value of fever. Postepy Hig Med Dosw 2003; 57: 531-54. PMID 14737969
9. ^ Su, F.; Nguyen, N.D.; Wang, Z.; Cai, Y.; Rogiers, P.; Vincent, J.L. Fever control in septic shock: beneficial or harmful? Shock 2005; 23: 516-20. PMID 15897803
10. ^ Schulman, C.I.; Namias, N.; Doherty, J., et al. The effect of antipyretic therapy upon outcomes in critically ill patients: a randomized, prospective study. Surg Infect (Larchmt) 2005; 6:369-75. PMID 16433601
11. ^ Rantala S, Vuopio-Varkila J, Vuento R, Huhtala H, Syrjänen J. Predictors of mortality in beta-hemolytic streptococcal bacteremia: A population-based study. J Infect. March 2, 2009. PMID 19261333
12. ^ Fischler, M.P.; Reinhart, W.H. Fever: friend or enemy? Schweiz Med Wochenschr 1997; 127: 864-70. PMID 9289813
13. ^ Craven, R and Hirnle, C. (2006). Fundamentals of nursing: Human health and function. Fourth edition. p. 1044
14. ^ ^{a b} Lewis, SM, Heitkemper, MM, and Dirksen, SR. (2007). Medical-surgical nursing: Assessment and management of clinical problems. sixth edition. p. 212
15. ^ Craven,R and Hirnle,C. (2006). "Fundamentals of nursing: Human health and function. Forth edition.". Antipyretics 11 (7-8): 1044. PMID 15636181. 

Further reading

• Rhoades, R. and Pflanzer, R. Human physiology, third edition, chapter 27 Regulation of body temperature, p. 820 Clinical focus: pathogenesis of fever. ISBN 0-03-005159-2
• Kasper, D.L.; Braunwald, E.; Fauci, A.S.; Hauser, S.L.; Longo, D.L.; Jameson, J.L. Harrison's Principles of Internal Medicine. New York: McGraw-Hill, 2005. ISBN 0-07-139140-1.

External links

• What to do if your child has a fever from Seattle Children's Hospital
• Fever and Taking Your Child's Temperature
• US National Institute of Health factsheet
• BUPA factsheet

v • d • e Symptoms and signs: general (R50-R69, 780-789) Fever Hyperpyrexia - Fever of unknown origin Pain Headache - Chronic pain Malaise/Fatigue Asthenia - Debility Fainting/syncope Vasovagal syncope - Carotid sinus syncope - Heat syncope Ingestion food and fluid intake (Anorexia, Polydipsia, Polyphagia) - Cachexia - Xerostomia Anorexia/Weight loss Hemodynamic Shock: Cardiogenic - Hypovolemic - Distributive (Septic, Neurogenic) Edema: Peripheral edema - Anasarca Hyperaemia: Functional - Reactive Lymphadenopathy Underdevelopment Delayed milestone - Failure to thrive - Short stature (Idiopathic) - Growth failure Other Seizure (Febrile seizure) Hyperhidrosis (Sleep hyperhidrosis) Clubbing - Tenderness Flu-like syndrome

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Dansk (Danish)
n. - feber, febersygdom, ophidselse
v. tr. - ophidse
v. intr. - give feber, få feber, blive smittet med en febersygdom

idioms:

• fever pitch    voldsom ophidselse

Nederlands (Dutch)
koorts, opwinding, rage, opwinden, koorts krijgen

Français (French)
n. - fièvre
v. tr. - enfiévrer
v. intr. - s'exciter fébrilement, s'enfiévrer

idioms:

• fever pitch    poussée de fièvre

Deutsch (German)
n. - Fieber(krankheit), Aufregung
v. - in Aufregung versetzen, fiebern

idioms:

• fever pitch    Zustand höchster Erregung

Ελληνική (Greek)
n. - (παθολ.) πυρετός, θέρμη, πυρετώδης δραστηριότητα, έξαψη
v. - επιφέρω/προκαλώ πυρετό

idioms:

• fever pitch    υπερδιέγερση

Italiano (Italian)
febbre

idioms:

• fever pitch    stato febbrile
• rheumatic fever    febbre reumatica

Português (Portuguese)
n. - febre (f)
v. - causar febre a

idioms:

• fever pitch    o grau mais alto
• rheumatic fever    febre (f) reumática (Med.)

Русский (Russian)
жар, лихорадка, температура, взволнованность

idioms:

• fever pitch    рьяность
• rheumatic fever    ревматизм

Español (Spanish)
n. - fiebre, calentura, temperatura
v. tr. - dar fiebre, enardecer
v. intr. - dar fiebre, enardecer

idioms:

• fever pitch    punto culminante

Svenska (Swedish)
n. - feber, feberaktigt tillstånd (bildl.)
v. - ge feber, få feber

中文（简体）(Chinese (Simplified))
发烧, 热病, 发热, 使发烧, 使狂热, 使高度兴奋, 狂热, 高度兴奋

idioms:

• fever pitch    狂热, 极度兴奋

中文（繁體）(Chinese (Traditional))
n. - 發燒, 熱病, 發熱
v. tr. - 使發燒, 使狂熱, 使高度興奮
v. intr. - 發燒, 狂熱, 高度興奮

idioms:

• fever pitch    狂熱, 極度興奮

한국어 (Korean)
n. - 열, 열병, 흥분
v. tr. - 발열하다, 열광적으로 활동하다
v. intr. - 열나게 하다, 열광시키다

日本語 (Japanese)
n. - 熱, 熱病, 異常に高まった状態, 熱狂, 発熱, 興奮

idioms:

• fever pitch    異常な興奮, 熱狂

العربيه (Arabic)
‏(الاسم) حمى , حرارة (فعل) يرفع الحرارة‏

עברית (Hebrew)
n. - ‮חום, קדחת, עצבנות, מתח‬
v. tr. - ‮גרם חום או קדחת‬
v. intr. - ‮קדח מחום, קיבל חום‬

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