pneumonia

(nʊ-mōn'yə, nyʊ-)

[New Latin, from Greek pneumoniā, lung disease, alteration (influenced by pneuma, breath) of pleumoniā, from pleumōn, lung.]

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Key Terms: Antineoplastic, Free radicals, Necrosis, Oncologist, Photodynamic therapy, Photosensitizing agents, Porphyrins.

Description

One of the most common pulmonary complications affecting cancer patients, pneumonia is a potentially life-threatening inflammation of one or both lungs.

Causes

Serious side effects in cancer patients most often occur in the lungs and may indicate that the cancer is progressing or that the patient has developed a new problem. Both cancer and the therapies used to treat it can injure the lungs or weaken the immune system in ways that make cancer patients especially susceptible to the bacteria, fungi, viruses, and other organisms that cause pneumonia.

Tumors and infections can block the patient's airway or limit the lungs' ability to rid themselves of fluid and other accumulated secretions that make breathing difficult. Other factors that increase a cancer patient's risk of developing pneumonia include:

• radiation therapy
• chemotherapy
• surgery
• depressed white blood cell count (neutropenia)
• antibiotics
• steroids
• malnutrition
• limited mobility
• splenectomy-immune system deficits

The risk of developing pneumonia is greatest for a cancer patient who has one or more additional health problems.

Treatments

Pneumonia in cancer patients must be treated promptly in order to speed recovery and prevent complications that could arise if the inflammation were allowed to linger. Treatment always includes bed rest and coughing to expel phlegm and other fluids from the lungs (productive cough). To determine which course of treatment would be most appropriate, a doctor considers when symptoms first appeared, what pattern the illness has followed, and whether cancer or its treatments have diminished the patient's infection-fighting ability (immune response).

A doctor generally prescribes broad-spectrum oral antibiotics if:

• the patient has had a fever for less than a week
• pneumonia has not spread beyond the lung area where it originated
• the patient's cancer is responding to treatment
• the patient is otherwise in good health

The doctor uses a flexible tube (bronchoscope) to examine the lungs and airway (bronchoscopy) for inflammation, swelling, obstruction, and other abnormalities and washes the lungs (bronchoalveolar lavage) with a mucus-dissolving solution if:

• pneumonia is extensive, aggressive, or severe
• antibiotics don't clear the infection
• the patient is very ill

The doctor may also remove a small piece of lung tissue (transbronchial biopsy) for microscopic examination and cultures, and prescribe medication to combat fungal and viral organisms that might be responsible for the patient's symptoms. If the patient's condition continues to worsen, the doctor may remove additional lung tissue (thoracic needle biopsy or open lung biopsy) for microscopic analysis and cultures.

Alternative and Complementary Therapies

Non-medical treatments will not cure pneumonia but may relieve symptoms and make the patient more comfortable. All of these therapies require the treating doctor's approval.

Accupuncture

Accupuncture may relieve congestion and reduce fatigue.

Essential Oils

Added to a warm bath or vaporizer, essential oils of eucalyptus (Eucalyptus globus), lavender (Lavandula officinalis), or pine (Abies sibirica) can create a fragrant steam that helps the patient breathe more easily. Because steam inhalations can irritate the lungs, individuals who have asthma should not use them.

Postural Drainage

A strenuous exercise that can help clear phlegm from the lungs, postural drainage should be practiced only with a doctor's approval and in the presence of a person who can provide support for a patient who becomes tired or weak.

Leaning over the side of the bed with forearms braced on the floor, the patient coughs up phlegm and spits it into a container. If the patient cannot cough productively enough to dislodge phlegm, the support person can help clear lung secretions by pounding gently on the patient's upper back. Postural drainage should be performed three times a day. Each session should last between five and 15 minutes, unless the patient tires or weakens sooner.

Massage

After the patient's fever has broken, gently massaging the upper back may relieve congestion and encourage productive cough.

Herbal Remedies

Homemade cough medicines (expectorants) containing licorice (Glycyrrhiza glabra), black cherry (Prunus serotina) bark, raw onions, honey, and other natural ingredients can relieve congestion and encourage productive cough. Because natural substances can be poisonous, they should be used only with a doctor's approval and according to label directions.

Eating raw garlic (Allium sativum) or taking garlic supplements is believed to strengthen the immune system. Echinacea, brewed as tea or taken in liquid or capsule form, may help some patients recover more quickly.

VITAMINS Zinc supplements and large doses of Vitamins A, C, and E may strengthen the patient's immune system. Because large doses of some vitamins can cause diarrhea and other serious side effects, they should not be taken without a doctor's approval. Additionally, large doses of vitamins and herbal remedies may interfere with the primary cancer treatment programs. Approval from the treating doctor is imperative.

Resources

Books

Ito, James, MD. "Infectious Complications." In Cancer Management: A Multidisciplinary Approach, edited by R. Pazdur, et al., 4th ed. New York: PRR Inc., 2000.

Stockdale-Wooley, R., and L. Norton. "Pulmonary Function." In Handbook of Oncology Nursing, edited by B. Johnson and J. Gross, 3rd ed. Sudbury, MA: Jones and Bartlett Publishers, 2001.

Other

American Lung Association Fact Sheet. [cited July 3, 2005]. .

—Maureen Haggerty

An acute or chronic inflammatory disease of the lungs. More specifically when inflammation is caused by an infectious agent, the condition is called pneumonia; when the inflammatory process in the lung is not related to an infectious organism, it is called pneumonitis.

An estimated 45 million cases of infectious pneumonia occur annually in the United States, with up to 50,000 deaths directly attributable to it. Pneumonia is a common immediate cause of death in persons with a variety of underlying diseases. With the use of immunosuppressive and chemotherapeutic agents for treating transplant and cancer patients, pneumonia caused by infectious agents that usually do not cause infections in healthy persons (that is, pneumonia as an opportunistic infection) has become commonplace. Moreover, individuals with acquired immune deficiency syndrome (AIDS) usually die from an opportunistic infection, such as pneumocystis pneumonia or cytomegalovirus pneumonia. Concurrent with the variable and expanding etiology of pneumonia and the more frequent occurrence of opportunistic infections is the development of new antibiotics and other drugs used in the treatment of pneumonia. See also Acquired immune deficiency syndrome (AIDS); Opportunistic infections.

Bacteria, as a group, are the most common cause of infectious pneumonia, although influenza virus has replaced Streptococcus pneumoniae (Diplococcus pneumoniae) as the most common single agent. Some of the bacteria are normal inhabitants of the body and proliferate to cause disease only under certain conditions. Other bacteria are contaminants of food or water.

Most bacteria cause one of two main morphologic forms of inflammation in the lung. Streptococcus pneumoniae causes lobar pneumonia, in which an entire lobe of a lung or a large portion of a lobe becomes consolidated (firm, dense) and nonfunctional secondary to an influx of fluid and acute inflammatory cells that represent a reaction to the bacteria. This type of pneumonia is uncommon today, usually occurring in people who have poor hygiene and are debilitated. If lobar pneumonia is treated adequately, the inflammatory process may entirely disappear, although in some instances it undergoes a process called organization, in which the inflammatory tissue changes into fibrous tissue, usually rendering that portion of the lung nonfunctional.

The other morphologic form of pneumonia, which is caused by the majority of bacteria, is called bronchopneumonia. In this form there is patchy consolidation of lung tissue, usually around the small bronchi and bronchioles, again most frequently in the lower lobes. This type of pneumonia may also undergo complete resolution if there is adequate treatment, although rarely it organizes.

Viral pneumonia is usually a diffuse process throughout the lung and produces a different type of inflammatory reaction than is seen in bronchopneumonia or lobar pneumonia. Mycoplasma pneumonia, caused by Mycoplasma pneumoniae, is referred to as primary atypical pneumonia and causes an inflammatory reaction similar to that of viral pneumonia.

Pneumonia can be caused by a variety of other fungal organisms, especially in debilitated persons such as those with cancer or AIDS. Mycobacterium tuberculosis, the causative agent of pulmonary tuberculosis, produces an inflammatory reaction similar to fungal organisms. See also Mycobacterial diseases; Tuberculosis.

Legionella pneumonia, initially called Legionnaire's disease, is caused by bacteria of the genus Legionella. The condition is frequently referred to under the broader name of legionellosis. See also Legionnaires' disease.

The signs and symptoms of pneumonia and pneumonitis are usually nonspecific, consisting of fever, chills, shortness of breath, and chest pain. Fever and chills are more frequently associated with infectious pneumonias but may also be seen in pneumonitis. The physical examination of a person with pneumonia or pneumonitis may reveal abnormal lung sounds indicative of regions of consolidation of lung tissue. A chest x-ray also shows the consolidation, which appears as an area of increased opacity (white area). Cultures of sputum or bronchial secretions may identify an infectious organism capable of causing the pneumonia.

The treatment of pneumonia and pneumonitis depends on the cause. Bacterial pneumonias are treated with antimicrobial agents. If the organisms can be cultured, the sensitivity of the organism to a specific antibiotic can be determined. Viral pneumonia is difficult to treat, as most drugs only help control the symptoms. The treatment of pneumonitis depends on identifying its cause; many cases are treated with cortisone-type medicines.

Definition

Pneumonia is an infection of the lungs that can be caused by nearly any class of organism known to cause human infections, including bacteria, viruses, fungi, and parasites. It results in an inflammatory response within the small air spaces of the lung (alveoli).

Description

Pneumonia can develop gradually in children after exposure to the causative organism, or it can develop quickly after another illness, reducing the lungs' ability to receive and distribute oxygen. It can be mild and easily cured with antibiotics and rest, or it can be severe and require hospitalization. The onset, duration, and severity of pneumonia depend upon the type of infective organism invading the body and the response of the child's immune system in fighting the infection. Respiratory distress represents 20 percent of all admissions of children to hospitals, and pneumonia is the underlying cause of most of these admissions.

To understand pneumonia, it is important to understand the basic anatomic features of the respiratory system. The human respiratory system begins at the nose and mouth, where air is breathed in (inspired) and out (expired). The nasopharynx is the air tube extending from the nose that directs air into the lungs. Air breathed in through the mouth travels through the oropharynx, which also carries swallowed food, water, and salivary secretions through the food tube (esophagus) and then into the stomach. The nasopharynx and oropharynx merge into the larynx, which is protected by a trap door called the epiglottis. The epiglottis normally prevents substances that have been swallowed, as well as substances that have been regurgitated (vomited), from heading down through the larynx into the lungs.

The larynx flows into the trachea, which is the broadest part of the respiratory tract. The trachea divides into the right and left bronchi, each branching off into multiple smaller bronchi that course throughout the lung tissue. Each bronchus divides into tubes of smaller and smaller diameter, finally ending in the terminal bronchioles. The alveoli, in which oxygen and carbon dioxide are exchanged, are clustered at the ends of the bronchioles. Lung stroma, the tissue of the lung, serves a supportive role for the bronchi, bronchioles, and alveoli.

The main function of the respiratory system is to help distribute oxygen, the most important energy source for the body's cells. Oxygen enters the body as inspired air and travels through the respiratory system to the alveoli. The oxygen is then picked up by hemoglobin, the oxygen-carrying protein in red blood cells, and delivered throughout the body through the circulatory system. Oxygen in the inspired air is exchanged within the alveoli of the lungs for carbon dioxide, a waste product of human metabolism. Carbon dioxide leaves the lungs during expiration.

The healthy human lung is sterile, with no normally resident bacteria or viruses, unlike the upper respiratory system and parts of the gastrointestinal system, where bacteria dwell even in a healthy state. Multiple safeguards along the path of the respiratory system are designed to keep invading organisms from causing infection. The first line of defense includes tiny hairs in the nostrils that filter out large particles. The epiglottis helps prevent food and other swallowed substances from entering the larynx and the trachea. Sneezing and coughing, both provoked by the presence of irritants within the respiratory system, help to clear such irritants from the respiratory tract. Mucus produced through the respiratory system also serves to trap dust and infectious organisms. Tiny hair like projections (cilia) from cells lining the respiratory tract beat constantly to move debris trapped by mucus upwards and out of the respiratory tract. This mechanism of protection is referred to as the mucociliary escalator. Finally, cells lining the respiratory tract produce several types of immune substances that protect against various organisms. Other cells (macrophages) along the respiratory tract surround and kill invading organisms.

Organisms that cause pneumonia, then, are usually prevented from entering the lungs by virtue of these host defenses. However, when a large number of organisms are encountered at once or when the immune system is weakened, the usual defenses may be overwhelmed and infection may occur. This can happen either by inhaling contaminated air droplets or by the aspiration of organisms inhabiting the upper airways. Aspiration pneumonia is a type of pneumonia in which something is aspirated from the upper airway into the lungs. This can be food from the mouth, a foreign object or substance that has entered the mouth, or regurgitated stomach contents (vomitus) aspirated into the lungs as it travels to the mouth.

The invading organism causing pneumonia provokes an immune response in the lungs that causes inflammation of the lung tissue (pneumonitis), a condition that actually makes the lung environment more ideal for infection. Small blood vessels in the lungs (capillaries) begin to empty protein-rich fluid into the alveoli, a condition that results in a less functional area for oxygen-carbon dioxide exchange. The individual becomes relatively oxygen deprived, while retaining potentially damaging carbon dioxide. This results in rapid respiration (tachypnea or faster and faster breathing) in an effort to bring in more oxygen and blow off more carbon dioxide.

Consolidation, a feature of bacterial pneumonia, occurs when the alveoli, which are normally hollow air spaces within the lung, instead become solid due to quantities of fluid and debris. Viral pneumonias and mycoplasma pneumonias do not result in consolidation. These types of pneumonia primarily infect the walls of the alveoli and the stroma of the lung. Bacterial and viral pneumonia occur mostly in winter months, while mycoplasma pneumonia is more common in summer and fall.

Bacterial pneumonia develops after the child inhales or aspirates pathogens. Viral pneumonia stems primarily from inhaling infected droplets from the upper airway into the lungs. In neonates, pneumonia may result from colonization of the infant's nasopharynx by organisms that were in the birth canal at the time of delivery.

In addition to exposure to sufficient quantities of causative organisms, certain other conditions can increase the risk of pneumonia. These include the following:

• abnormal anatomical structure, particularly of the chest or lungs
• cigarette smoke, inhaled directly by a smoker or second-hand
• immune system deficiencies (common variable immunodeficiency, immunoglobulin deficiency syndromes, HIV infection, and others)
• swallowing difficulties as a result of stroke or seizures
• intoxication by alcohol and drugs that may interfere with normal cough reflex and decrease the chance of clearing unwanted debris from the respiratory tract
• viruses that may interfere with ciliary function, allowing themselves or other invading microorganisms such as bacteria access to the lower respiratory tract
• various chronic conditions such as asthma, cystic fibrosis, diabetes, emphysema, and neuromuscular diseases that may interfere with the seal of the epiglottis
• advanced age and associated immune system weakness
• esophageal disorders that may result in stomach contents passing upwards
• genetic factors and associated changes in DNA
• post-operative complications including the use of certain therapeutic drugs, suppressed cough reflex, breathing difficulties, and pain at the surgical site that affects breathing
• malnutrition
• radiation treatment for breast cancer, which may weaken lung tissue

The epidemic of immmunodeficiency virus (HIV), the virus that causes acquired immunodeficiency syndrome (AIDS), has resulted in a huge increase in the incidence of pneumonia. Because AIDS results in immune system suppression, individuals with AIDS are highly susceptible to all kinds of pneumonia, including some previously rare parasitic types that would not cause illness in someone with a normal immune system.

Pneumonia is also the most common fatal infection acquired by already hospitalized patients. Even in nonfatal cases, pneumonia is a significant economic burden on the healthcare system. One study estimates that U.S. workers who develop pneumonia cost employers five times as much in health care as the average worker.

Transmission

Pneumonia is not usually passed from one person to another. The bacterial and viral organisms that cause pneumonia, however, can be transmitted through airborne or direct contact.

Demographics

Every year in the United States, two million people of all ages develop pneumonia, including 4 percent of all the children in the country. It is the sixth most common disease leading to death and the fourth leading cause of death in the elderly; 40,000 to 70,000 people die from pneumonia each year. The incidence of pneumonia in children younger than one year of age is 35 to 40 per 1,000; 30 to 35 per 1,000 children ages two to four; and 15 per 1,000 children between ages five and nine. Fewer than 10 children in 1,000 over age nine are reported to develop pneumonia. The Centers for Disease Control and Prevention (CDC) reports that the number of deaths from pneumonia in the United States declined between 2001 and 2004.

Causes and Symptoms

The list of organisms that can cause pneumonia is lengthy and includes nearly every class of infecting organism: viruses, bacteria, bacteria-like organisms, fungi, and parasites (including certain worms). Different organisms are more frequently encountered by different age groups, and other individual characteristics may increase risk for infection by particular types of organisms:

• Viruses cause the majority of pneumonias in young children, especially respiratory syncytial virus, parainfluenza and influenza viruses, and adenovirus.
• Adults are more frequently infected with bacteria such as Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus.
• Pneumonia in older children and young adults is often caused by the bacteria-like Mycoplasma pneumoniae, the cause of pneumonia that is often called "walking" pneumonia.
• Pneumocystis carinii causes pneumonia in immunosuppressed individuals such as patients being treated with chemotherapy or people with AIDS. Classically considered a parasite, it appears to be more related to fungi.
• Chlamydia psittaci can be infective in some individuals, such as poultry farm workers, who have direct contact with bird droppings.

Pneumonia is suspected in a child who has symptoms such as fever, cough, chest pain, difficulty breathing (shortness of breath or dyspnea), and an increased number of breaths per minute (respiration). Fever with a shaking chill is even more suspicious. Mucus production is typically increased and leaky capillaries in the lungs may tinge the mucus with blood. The alveoli fill further with fluid and debris from the large number of white blood cells being produced to fight the infection. Children may cough up clumps of sputum or phlegm, secretions produced in the alveoli during the infection or inflammatory condition. These clumps may appear streaked with pus or blood. In severe pneumonia, mucus plugs and the accumulation of fluid together decrease the efficiency of gas exchange in the lung, resulting in signs of oxygen deprivation. Reduced oxygen levels in the blood may produce a blue appearance of the nail beds or lips (cyanosis).

Diagnosis

Diagnosis is based on the parents' report of the onset of illness and the symptoms that have developed, combined with examination of the chest. Physical examination may indicate labored breathing. Listening with a stethoscope may reveal abnormal crackling sounds (rales), and tapping on the back, which normally yields a resonant sound due to air filling the alveoli, may yield a dull thump if the alveoli are filled with fluid and debris.

Laboratory diagnostic tests may include staining sputum samples on a glass slide and looking at the stained specimen under a microscope to determine if white cells, red cells, or bacteria are present. Identification of the specific type of bacteria may require culturing the sputum, a microbiological technique that identifies disease-causing bacterial organisms in infected material. A small sample of sputum will be streaked on a special plate filled with medium that allows the specific organism to be grown in the laboratory under certain conditions. The bacteria can then be identified and, by performing antibiotic sensitivity tests on the bacteria, appropriate treatment can usually be prescribed. In addition, oxygen and carbon dioxide levels may be measured (blood gases) and the exchange evaluated (oximetry).

If pneumonia is present, a rapid rate of respiration may be noted; tachypnea is defined as a respiratory rate over 50 respirations per minute in infants younger than one year. Older children will have tachypnea if the respiratory rate is greater than 40 per minute.

X-ray examination of the chest may reveal certain abnormal changes associated with pneumonia. Localized shadows obscuring areas of the lung may indicate a bacterial pneumonia, while streaky or patchy changes in the x-ray film may indicate viral or mycoplasma pneumonia. These changes on x ray, however, are known to lag in time behind actual symptoms.

Treatment

Prior to the discovery of penicillin and other antibiotics, bacterial pneumonia was almost always fatal. In the early 2000s, especially given early in the course of the disease, antibiotics are very effective against bacterial causes of pneumonia. Penicillin was, as of 2004, still the first choice for treating children with pneumonia unless the child is known to be penicillin-resistant. Oral amoxicillin or cephalosporins are often administered first in treating milder cases of pneumococcal pneumonia in children younger than age five, though they are not used in newborns. Erythromycin and tetracycline are broad-spectrum antibiotics that are known to improve recovery time for symptoms of mycoplasma pneumonia. They do not, however, eradicate the organisms. If the results of culture and sensitivity positively identify the causative bacteria, an antibiotic is prescribed for that demonstrated sensitivity. Viruses do not usually respond to antibiotics. Amantadine and acyclovir may be helpful against certain viral pneumonias.

Linezolid (Zyvox), the first of a new line of antibiotics known as oxazolidinones, is used to treat penicillin-resistant organisms that cause pneumonia. Another newer drug known as ertapenem (Invanz) is reported to be effective in treating bacterial pneumonia.

The child is also be given fluids and possibly drug therapy to thin mucus secretions (mucolytic agents) or medication to open the airways of the lung (brochodilators). Cough suppressants may be given as well as pain medication and fever-reducing medication. Hospitalized children may receive extra oxygen, respiratory therapy, and intravenous antibiotics and fluids.

Alternative Treatment

Vitamin C is known to improve immune response and to help reduce inflammation. Grape seed extract enhances immune system functioning and helps protect lung tissue. These are adjunctive measures that do not destroy the causative organism as antibiotics do. Although garlic and certain herbs such as yerba mansa may have antibiotic properties, they cannot replace specific antibiotics used to treat pneumonia.

Prognosis

Prognosis varies according to the type of organism causing the infection, the status of the immune system, and the overall health of the affected child. Generally, there are lower mortality rates from pneumonia in the United States than elsewhere in the world. Streptococcus pneumoniae, the most common organism causing pneumonia, has a significantly lower death rate of about 5 percent. More complications occur in the very young or very old with multiple areas of the lung infected simultaneously. The presence of chronic illnesses such as diabetes, cirrhosis, and congestive heart failure may increase the chance of complications. Individuals with immunodeficiency disorders, various types of cancer, or AIDS are also more prone to complications. In children, cystic fibrosis, aspiration problems, immunodeficiencies, and congenital or acquired lung malformation may increase the risk of pneumonia from S. pneumoniae.

Recovery following pneumonia with Mycoplasma pneumoniae is nearly 100 percent. However, in the very young or very old or immunodeficient, Staphylococcus aureus has a death rate of 30 to 40 percent. Similarly, infections with a number of gram negative bacteria (such as those in the gastrointestinal tract that can cause infection following aspiration) have a death rate of 25 to 50 percent.

Prevention

Because many bacterial pneumonias occur in people who were first infected with the influenza virus (the flu), yearly flu vaccinations can decrease the risk of pneumonia for the elderly and children or adults with chronic diseases such as asthma, cystic fibrosis, other lung or heart diseases, sickle cell anemia, diabetes, kidney disease, and cancer.

A specific vaccine against Streptococcus pneumoniae can be protective for people with chronic illnesses.

Immunodeficient individuals are at higher risk for infection with Pneumocystis carinii and are frequently put on a regular preventive drug regimen of trimethoprim sulfa and/or inhaled pentamidine to avoid pneumocystis pneumonia.

Parental Concerns

Pneumonia in a child can produce severe symptoms that can be frightening to both the child and parents, particularly when breathing is compromised or cyanosis is noted. When symptoms seem to suggest pneumonia, immediate attention allows early treatment so that breathing difficulties can be corrected quickly and drug therapy begun in order to destroy the causative organism. Parents can try to reassure young children and keep them as calm as possible, knowing that anxiety also increases breathing difficulties.

See also Common variable immunodeficiency.

Resources

Books

"Pneumonia." Section 6, Chapter 73 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers and Robert Berkow. Whitehouse Station, NJ: Merck Research Laboratories, 2003.

Organizations

American Lung Association. 1740 Broadway, New York, NY 10019. Web site: www.lungusa.org.

Centers for Disease Control and Prevention. 1600 Clifton Rd., NE, Atlanta, GA 30333. Web site: www.cdc.gov.

Web Sites

Cantu, Santos, Jr. "Pneumonia, Mycoplasma." eMedicine, July 13, 2001. Available online at www.emedicine.com/EMERG/topic467.htm (accessed November 22, 2004).

National Heart Lung and Blood Institute (NHLBI), Available online at www.nhlbi.nih.gov (accessed November 22, 2004).

[Article by: L. Lee Culvert Rosalyn Carson-DeWitt, MD Rebecca J. Frey, PhD]

A disease characterized by inflammation of the lungs. Pneumonia can be caused by many factors, including bacterial infections, viral infections, and the inhalation of chemical irritants.

Tutor's tip: This word was used in the 2006 Scripps National Spelling Bee finals.

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Inflammation of the parenchyma of the lung. It is often accompanied by inflammation of the airways and sometimes of the adjoining pleura. Clinically it is manifested by an increase in the rate and depth of respiration at all degrees of severity up to dyspnea. There is also cough, and abnormality of the breath sounds on auscultation. In bacterial pneumonia there is usually a severe toxemia, in viral pneumonia it is usually minor. See also bronchopneumonia, pleuropneumonia.

• Arabian foal p. — an inexorably progressive pneumonia of certain Arabian foals born with primary severe combined immunodeficiency in which adenovirus plays a dominant role but is complicated by other microorganisms, particularly Pneumocystis carinii.
• aspiration p. — see aspiration pneumonia.
• atypical p. — histologically the pneumonia is atypical in that there are no signs of acute inflammation and it is characterized by an exudation of eosinophilic, protein-rich fluid in the alveoli which may become organized to form a hyaline membrane. In animals that survive for several days there is epithelialization of the alveolar walls. In humans there is a primary atypical pneumonia caused by Mycoplasma pneumoniae. In animals the best known example is atypical interstitial pneumonia of cattle.
• bronchointerstitial p. — the lesions are centered on the bronchioles and a prominent feature is the accumulation of lymphocytes in interstitial tissue; typical of pneumonias caused by aerogenous virus infections, especially myxoviruses.
• brooder p. — see brooder pneumonia.
• chronic undifferentiated p. of sheep — see enzootic pneumonia.
• corynebacterial p. of foals — see corynebacterial pneumonia.
• cuffing p. — chronic undifferentiated pneumonia of sheep in which lymphofollicular sheaths around the bronchioles are a feature.
• equine cryptococcal p. — see epizootic lymphangitis.
• desquamative p. — a chronic pneumonia associated with Mycoplasma spp. and characterized by organization of the exudate within bronchioles and bronchi, and proliferation of the interstitial tissue and epithelium.
• desquamative interstitial p. — chronic pneumonia with desquamation of large alveolar cells and thickening of the walls of distal air passages; marked by dyspnea and nonproductive cough.
• embolic p. — results from hematogenous spread from an intravascular lesion elsewhere in the body. The best known example is caudal vena caval thrombosis.
• endogenous-lipid p. — focal alveolar accumulations of foamy, lipid-filled macrophages which may impede alveolar clearance. Usually an incidental postmortem finding in laboratory rodents, fur-bearing animals and uncommonly cats and dogs.
• enzootic p. — see enzootic pneumonia.
• fibrinous p. — an acute fulminating pneumonia, often lobar in distribution, characterized by a fibrinous exudate. Fibrinous describes the exudate, not the anatomical distribution so that the term fibrinous pneumonia should not be used interchangeably with lobar pneumonia.
• foreign body p. — see aspiration pneumonia.
• gangrenous p. — usually an accompaniment of aspiration pneumonia.
• giant-cell p. — a secondary lesion in dermatosis vegetans in pigs; lesions marked by the presence of a proliferative giant-cell type of diffuse interstitial pneumonia.
• granulomatous p. — has a slow course characterized by granulomatous, not exudative, lesions. Sporadic cases occur in immunodeficient animals. It is a characteristic of tuberculosis and systemic fungal infections, e.g. coccidioidomycosis.
• hypostatic p. — caused by pooling of blood and some decrease in viability of the dependent lung in an old, sick or debilitated animal that is in lateral recumbency for a long period. The infection is secondary to hypostasis.
• inhalation p. — see aspiration pneumonia.
• interstitial p. — pneumonia in which there is diffuse or patchy damage to alveolar septa widely distributed through the lungs. There is an early intra-alveolar exudative phase followed by significant proliferation and enlargement of the alveolar epithelial cells and a thickening of the interstitial tissue. Most interstitial pneumonias in animals are infectious including viral, bacterial, fungal and protozoal causes, but may be caused by chemical injury, acute pancreatitis or shock, as in acute respiratory distress syndrome.
• lipid p. — a specific type of aspiration pneumonia caused by the inhalation of oil droplets; most commonly associated with the forced administration of paraffin oil or cod-liver oil to cats. Called also medication pneumonia, lipoid pneumonia. See also aspiration pneumonia.
• lobar p. — a fulminating bronchopneumonia in which entire pulmonary lobes are diffusively inflamed and then consolidated. Pneumonic pasteurellosis in cattle is the type disease. The animal is critically ill with anoxia and toxemia.
• lobular p. — an oldfashioned term for bronchopneumonia.
• lymphoid interstitial p. — see maedi.
• ovine progressive p. — see maedi.
• parasitic p. — see lungworm disease.
• stable p. — see equine influenza.
• suppurative p. of foals — see corynebacterial pneumonia.
• uremic p. — occurs in dogs with terminal uremia; lesions characterized by absence of inflammatory cells.

An acute inflammation of the lungs, usually caused by inhaled microorganisms. The alveoli and bronchioles of the lungs become plugged with a fibrous exudate, seriously interfering with oxygen exchange.

• Diseases and Infestations - pneumonia: inflammation or infection of lungs in which air sacs fill with pus, causing coughing and chest pain

For other uses, see Pneumonia (disambiguation).

Pneumonia
Classification and external resources
A chest X-ray showing a very prominent wedge-shaped bacterial pneumonia in the right lung.
ICD-10	J12, J13, J14, J15, J16, J17, J18, P23
ICD-9	480-486, 770.0
DiseasesDB	10166
MedlinePlus	000145
eMedicine	topic list
MeSH	D011014

Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs (alveoli)—associated with fever, chest symptoms, and a lack of air space (consolidation) on a chest X-ray.^[1][2] Pneumonia is typically caused by an infection but there are a number of other causes.^[1] Infectious agents include: bacteria, viruses, fungi, and parasites.^[3]

Typical symptoms include cough, chest pain, fever, and difficulty breathing.^[4] Diagnostic tools include x-rays and examination of the sputum. Vaccines to prevent certain types of pneumonia are available. Treatment depends on the underlying cause. Presumed bacterial pneumonia is treated with antibiotics.

Although pneumonia was regarded by William Osler in the 19th century as "the captain of the men of death", the advent of antibiotic therapy and vaccines in the 20th century have seen radical improvements in survival outcomes. Nevertheless, in the third world, and among the very old, the very young and the chronically ill, pneumonia remains a leading cause of death.^[5]

Contents 1 Classification 2 Signs and symptoms 3 Cause 3.1 Bacteria 3.2 Viruses 3.3 Fungi 3.4 Parasites 3.5 Idiopathic 4 Pathophysiology 4.1 Viral 4.2 Bacterial 5 Diagnosis 5.1 Imaging 5.2 Microbiology 5.3 Differential diagnosis 6 Prevention 6.1 Vaccination 6.2 Environmental 6.3 Other 7 Management 7.1 Bacterial 7.2 Viral 7.3 Aspiration 8 Prognosis 8.1 Clinical prediction rules 8.2 Pleural effusion, empyema, and abscess 8.3 Respiratory and circulatory failure 9 Epidemiology 9.1 Children 10 History 11 Society and culture 12 References

Classification

Main article: Classification of pneumonia

Pneumonitis refers to lung inflammation; pneumonia refers to pneumonitis, usually due to infection but sometimes non infectious, that has the additional feature of pulmonary consolidation.^[6] Pneumonia can be classified in several ways. It is most commonly classified by where or how it was acquired (community-acquired, aspiration, healthcare-associated, hospital-acquired, and ventilator-associated pneumonia),^[7] but may also be classified by the area of lung affected (lobar pneumonia, bronchial pneumonia and acute interstitial pneumonia),^[7] or by the causative organism.^[8] Pneumonia in children may additionally be classified based on signs and symptoms as non-severe, severe, or very severe.^[9]

Signs and symptoms

Main symptoms of infectious pneumonia

People with infectious pneumonia often have a productive cough, fever accompanied by shaking chills, shortness of breath, sharp or stabbing chest pain during deep breaths, confusion, and an increased respiratory rate.^[10] In the elderly, confusion may be the most prominent symptom.^[10] The typical symptoms in children under five are fever, cough, and fast or difficult breathing.^[11] Fever, however, is not very specific, as it occurs in many other common illnesses, and may be absent in those with severe disease or malnutrition. In addition, a cough is frequently absent in children less than 2 months old.^[11] More severe symptoms may include: central cyanosis, decreased thirst, convulsions, persistent vomiting, or a decreased level of consciousness.^[11]

Symptoms frequency in pneumonia[12]
Symptom	Frequency
Cough	79–91%
Fatigue	90%
Fever	71–75%
Shortness of breath	67–75%
Sputum	60–65%
Chest pain	39–49%

Some causes of pneumonia are associated with classic, but non-specific, clinical characteristics. Pneumonia caused by Legionella may occur with abdominal pain, diarrhea, or confusion,^[13] while pneumonia caused by Streptococcus pneumoniae is associated with rusty colored sputum,^[14] and pneumonia caused by Klebsiella may have bloody sputum often described as "currant jelly".^[12]

Physical examination may sometimes reveal low blood pressure, a high heart rate, or a low oxygen saturation. Examination of the chest may be normal, but may show decreased chest expansion on the affected side. Harsh breath sounds from the larger airways that are transmitted through the inflamed lung are termed bronchial breathing, and are heard on auscultation with a stethoscope. Rales (or crackles) may be heard over the affected area during inspiration. Percussion may be dulled over the affected lung, and increased, rather than decreased, vocal resonance distinguishes pneumonia from a pleural effusion.^[10] Struggling to breathe, confusion, and blue-tinged skin are signs of a medical emergency.

Cause

Pneumonia is due primarily to infections, with less common causes including irritants and the unknown. Although more than one hundred strains of microorganisms can cause pneumonia, only a few are responsible for most cases. The most common types of infectious agents are viruses and bacteria, with its being less commonly due to fungi or parasites. Mixed infections with both viruses and bacteria may occur in up to 45% of infections in children and 15% of infections in adults.^[15] A causative agent is not isolated in approximately half of cases despite careful testing.^[16] The term pneumonia is sometimes more broadly applied to inflammation of the lung (for example caused by autoimmune disease, chemical burns or drug reactions), however this is more accurately referred to as pneumonitis.^[17][18]

Bacteria

Main article: Bacterial pneumonia

The bacterium Streptococcus pneumoniae, a common cause of pneumonia, imaged by an electron microscope

Bacteria are the most common cause of community acquired pneumonia, with Streptococcus pneumoniae isolated in nearly 50% of cases.^[19][7] Other commonly isolated bacteria include: Haemophilus influenzae in 20%, Chlamydophila pneumoniae in 13%, Mycoplasma pneumoniae in 3%,^[7], Staphylococcus aureus, Moraxella catarrhalis, Legionella pneumophila and gram-negative bacilli.^[16]

Risk factors for infection depend on the organism involved.^[16] Alcoholism is associated with Streptococcus pneumoniae, anaerobic organisms, and Mycobacterium tuberculosis, smoking is associated with Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Legionella pneumophila, exposure to bird with Chlamydia psittaci, farm animals with Coxiella burnetti, aspiration of stomach contents with anaerobes, and cystic fibrosis with Pseudomonas aeruginosa and Staphylococcus aureus.^[16] Streptococcus pneumoniae is more common in the winter.^[16]

Viruses

Main article: Viral pneumonia

In adults, viruses account for approximately a third of pneumonia cases.^[15] Commonly implicated agents include: rhinoviruses,^[15]coronaviruses,^[15] influenza virus,^[20] respiratory syncytial virus (RSV),^[20] adenovirus,^[20] and parainfluenza.^[20] Herpes simplex virus is a rare cause of pneumonia, except in newborns. People with weakened immune systems are at increased risk of pneumonia caused by cytomegalovirus (CMV).

Fungi

Main article: Fungal pneumonia

Fungal pneumonia is uncommon,^[16] but it may occur in individuals with weakened immune systems due to AIDS, immunosuppressive drugs, or other medical problems. The pathophysiology of pneumonia caused by fungi is similar to that of bacterial pneumonia. Fungal pneumonia is most often caused by Histoplasma capsulatum, blastomyces, Cryptococcus neoformans, Pneumocystis jiroveci, and Coccidioides immitis. Histoplasmosis is most common in the Mississippi River basin, and coccidioidomycosis is most common in the southwestern United States.^[16]

Parasites

Main article: Parasitic pneumonia

A variety of parasites can affect the lungs. These parasites typically enter the body through the skin or the mouth. Once inside the body, they travel to the lungs, usually through the blood. In parasitic pneumonia, as with other kinds of pneumonia, a combination of cellular destruction and immune response causes disruption of oxygen transportation. One type of white blood cell, the eosinophil, responds vigorously to parasite infection. Eosinophils in the lungs can lead to eosinophilic pneumonia, thus complicating the underlying parasitic pneumonia. The most common parasites causing pneumonia are Toxoplasma gondii, Strongyloides stercoralis, and Ascariasis.

Idiopathic

Main article: Idiopathic interstitial pneumonia

Idiopathic interstitial pneumonia or noninfectious pneumonia^[21] are a class of diffuse lung diseases. They include: diffuse alveolar damage, organizing pneumonia, nonspecific interstitial pneumonia, lymphocytic interstitial pneumonia, desquamative interstitial pneumonia, respiratory bronchiolitis interstitial lung disease, and usual interstitial pneumonia.^[22]

Pathophysiology

Pneumonia fills the lung's alveoli with fluid, hindering oxygenation. The alveolus on the left is normal, whereas the one on the right is full of fluid from pneumonia.

Pneumonia frequently starts as a upper respiratory tract infection that moves into the lower respiratory tract.^[23]

Viral

Viruses invade cells in order to reproduce. Typically, a virus reaches the lungs when airborne droplets are inhaled through the mouth or nose. Once in the lungs, the virus invades the cells lining the airways and alveoli. This invasion often leads to cell death, either from damage to the cell by the virus or from a protective process called apoptosis in which the infected cell destroys itself before it can be used as a conduit for virus reproduction. When the immune system responds to the viral infection, even more lung damage occurs. White blood cells, mainly lymphocytes, activate certain chemical cytokines that allow fluid to leak into the alveoli. This combination of cell destruction and fluid-filled alveoli interrupts the normal transportation of oxygen into the bloodstream.

As well as damaging the lungs, many viruses affect other organs and thus disrupt many body functions. Viruses can also make the body more susceptible to other bacterial infections; in this way bacterial pneumonia can arise as a co-morbid condition.^[20]

Bacterial

Bacteria typically enter the lung when airborne droplets are inhaled, but can also reach the lung through the bloodstream when there is an infection in another part of the body. Many bacteria live in parts of the upper respiratory tract, such as the nose, mouth, and sinuses, and can easily be inhaled into the alveoli. Once inside, bacteria may invade the spaces between cells and between alveoli through connecting pores. This invasion triggers the immune system to send neutrophils, a type of defensive white blood cell, to the lungs. The neutrophils engulf and kill the offending organisms, and also release cytokines, causing a general activation of the immune system. This leads to the fever, chills, and fatigue common in bacterial and fungal pneumonia. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli and interrupt normal oxygen transportation.

Diagnosis

	Crackles Crackles heard in the lungs of a person with pneumonia using a stethoscope.
Problems listening to this file? See media help.

Pneumonia is typically diagnosed based on a combination of physical signs and a chest X-ray.^[24] Confirming the underlying cause can be difficult, however, with no definitive test able to distinguish between bacterial and not-bacterial origin.^[15][24] The World Health Organization has defined pneumonia in children clinically based on either a cough or difficulty breathing and a rapid respiratory rate, chest indrawing, or a decreased level of consciousness.^[25] A rapid respiratory rate is defined as greater than 60 breaths per minute in children under 2 months old, 50 breaths per minute in children two months to one year old, or greater than 40 breaths per minute in children one to five years old.^[25] In children, an increased respiratory rate and lower chest indrawing are more sensitive than hearing chest crackles with a stethoscope.^[11]

In adults, investigations are in general not needed in mild cases^[26] as if all vital signs and auscultation are normal the risk of pneumonia is very low.^[27]In those requiring admission to a hospital, pulse oximetry, chest radiography, and blood tests including a complete blood count, serum electrolytes, C-reactive protein, and possibly liver function tests are recommended.^[26] The diagnosis of influenza-like illness can be made based on the presenting signs and symptoms however verification of an influenza infection requires testing.^[28] Thus treatment is frequently based on the presence of influenza in the community or a rapid influenza test.^[28]

Imaging

CT of the chest demonstrating right sided pneumonia (left side of the image).

A chest radiograph is frequently used in diagnosis.^[11] In people with mild disease, imaging is needed only in those with potential complications, those who have not improved with treatment, or those in which the cause in uncertain.^[11][26] If a person is sufficiently sick to require hospitalization, a chest radiograph is recommended.^[26] Findings do not always correlate with severity of disease and do not reliably distinguish between bacterial infection and viral infection.^[11]

X-ray signs of bacterial community acquired pneumonia classically show lung consolidation of one lung segmental lobe.^[7] However, radiographic findings may be variable, especially in other types of pneumonia.^[7] Aspiration pneumonia may present with bilateral opacities primarily in the bases of the lungs and on the right side.^[7] Radiographs of viral pneumonia cases may appear normal, hyper-inflated, have bilateral patchy areas, or present similar to bacterial pneumonia with lobar consolidation.^[7] A CT scan can give additional information in indeterminate cases.^[7]

Radiologic findings often lag behind clinical findings, especially in the presence of dehydration, thus many clinicians make a diagnosis of "clinical pneumonia" on the basis of of history and crackles on examination. ^[29] This lag is more often remarked in Pneumocystis carinii pneumonia, where chest radiograph findings may be normal in 10-39% of patients.^[30]

Microbiology

For people managed in the community figuring out the causative agent is not cost effective, and typically does not alter management.^[11] For those not responsive to treatment, sputum culture should be considered, and culture for Mycobacterium tuberculosis should be carried out in those with a chronic productive cough.^[26] Testing for other specific organisms may be recommended during outbreaks, for public health reasons.^[26] In those who are hospitalized for severe disease both sputum and blood cultures are recommended.^[26] Viral infections can be confirmed via detection of either the virus or its antigens with culture or polymerase chain reaction (PCR) among other techniques.^[15] With routine microbiological testing a causative agent is determined in only 15% of cases.^[10]

Differential diagnosis

Several diseases can present similar to pneumonia, including: chronic obstructive pulmonary disease (COPD), asthma, pulmonary edema, bronchiectasis, lung cancer, and pulmonary emboli.^[10] Unlike pneumonia, asthma and COPD typically present with wheezing, pulmonary edema presents with an abnormal electrocardiogram, cancer and bronchiectasis present with a cough of longer duration, and pulmonary emboli presents with acute onset sharp chest pain and shortness of breath.^[10]

Prevention

Prevention includes vaccination, environmental measures, and appropriately treating other diseases.^[11]

Vaccination

Vaccination is effective for preventing certain bacterial and viral pneumonias in both children and adults.

Influenza vaccines are modestly effective against influenza A and B.^[15][31] The Center for Disease Control and Prevention (CDC) recommends that everyone 6 months and older get yearly vaccination.^[32] When an influenza outbreak is occurring, medications such as amantadine, rimantadine, zanamivir, and oseltamivir can help prevent influenza.^[33][34]

Vaccinations against Haemophilus influenzae and Streptococcus pneumoniae have good evidence to support their use.^[23] Vaccinating children against Streptococcus pneumoniae has also led to a decreased incidence of these infections in adults, because many adults acquire infections from children. A vaccine against Streptococcus pneumoniae is also available for adults, and has been found to decrease the risk of invasive pneumococcal disease.^[35]

Environmental

Reducing indoor air pollution is recommended^[11] as is smoking cessation.^[26]

Other

Appropriately treating underlying illnesses (such as AIDS) can decrease a person's risk of pneumonia.

There are several ways to prevent pneumonia in newborn infants. Testing pregnant women for Group B Streptococcus and Chlamydia trachomatis, and giving antibiotic treatment, if needed, reduces pneumonia in infants. Suctioning the mouth and throat of infants with meconium-stained amniotic fluid decreases the rate of aspiration pneumonia.

Management

CURB-65
Symptom	Points
Confusion	1
Urea>7mmol/l	1
Respiratory rate>30	1
SBP<90mmHg, DBP<60mmHg	1
Age>=65	1

Typically, oral antibiotics, rest, simple analgesics, and fluids suffice for complete resolution.^[26] However, those with other medical conditions, the elderly, or those with significant trouble breathing may require more advanced care. If the symptoms worsen, the pneumonia does not improve with home treatment, or complications occur, hospitalization may be required.^[26] Worldwide, approximately 7–13% of cases in children result in hospitalization^[11] while in the developed world between 22 and 42% of adults with community-acquired pneumonia are admitted.^[26] The CURB-65 score is useful for determining the need for admission in adults.^[26] If the score is 0 or 1 people can typically be managed at home, if it is 2 a short hospital stay or close follow up is needed, if it is 3–5 hospitalization is recommended.^[26] In children those with respiratory distress or oxygen saturations of less than 90% should be hospitalized.^[36] The utility of chest physiotherapy in pneumonia has not yet been determined.^[37] Over-the-counter cough medicine has not been found to be effective.^[38]

Bacterial

Antibiotics improve outcomes in those with bacterial pneumonia.^[39] Antibiotic choice depends initially on the characteristics of the person affected, such as age, underlying health, and the location the infection was acquired. In the UK, empiric treatment with amoxicillin is recommended as the first line for community-acquired pneumonia, with doxycycline or clarithromycin as alternatives.^[26] In North America, where the "atypical" forms of community-acquired pneumonia are more common, macrolides (such as azithromycin), and doxycycline have displaced amoxicillin as first-line outpatient treatment in adults.^[19][40] In children with mild or moderate symptoms amoxicillin remains the first line.^[36] The use of fluoroquinolones in uncomplicated cases is discouraged due to concerns about side effects and resistance.^[19] The duration of treatment has traditionally been seven to ten days, but increasing evidence suggests that short courses (three to five days) are similarly effective.^[41] Antibiotics recommended for hospital-acquired pneumonia include third- and fourth-generation cephalosporins, carbapenems, fluoroquinolones, aminoglycosides, and vancomycin.^[42] These antibiotics, often given intravenously, may be used in combination.

Viral

Neuraminidase inhibitors may be used to treat viral pneumonia caused by influenza viruses (influenza A and influenza B).^[15] No specific antiviral medications are recommended for other types of community acquired viral pneumonias including SARS coronavirus, adenovirus, hantavirus, and parainfluenza virus.^[15] Influenza A may be treated with rimantadine or amantadine, while influenza A or B may be treated with oseltamivir, zanamivir or peramivir.^[15] These are of most benefit if they are started within 48 hours of the onset of symptoms.^[15] Many strains of H5N1 influenza A, also known as avian influenza or "bird flu," have shown resistance to rimantadine and amantadine.^[15] The use of antibiotics in viral pneumonia is recommended by some experts as it is impossible to rule out a complicating bacterial infection.^[15] The British Thoracic Society recommends that antibiotics be withheld in those with mild disease.^[15] The use of corticosteroids is controversial.^[15]

Aspiration

In general, aspiration pneumonitis is treated conservatively with antibiotics indicated only for aspiration pneumonia.^[43] The choice of antibiotic will depend on several factors, including the suspected causative organism and whether pneumonia was acquired in the community or developed in a hospital setting. Common options include clindamycin, a combination of a beta-lactam antibiotic and metronidazole, or an aminoglycoside.^[44] Corticosteroids are commonly used in aspiration pneumonia, but there is no evidence to support their effectiveness.^[44]

Prognosis

With treatment, most types of bacterial pneumonia can be cleared within two to four weeks^[45] and mortality is very low.^[15] Viral pneumonia may last longer, and mycoplasmal pneumonia may take four to six weeks to resolve completely.^[45] The eventual outcome of an episode of pneumonia depends on how ill the person is when he or she was first diagnosed.^[45] Before the advent of antibiotics mortality was typically 30% for hospitalized patients.^[16]

In the United States, about 5% of those diagnosed with pneumococcal pneumonia will die. In cases where the pneumonia progresses to blood infection, just over 20% will die.^[46]

The death rate (or mortality) also depends on the underlying cause of the pneumonia. Pneumonia caused by Mycoplasma, for instance, is associated with lower mortality. However, about half of the people who develop methicillin-resistant Staphylococcus aureus (MRSA) pneumonia while on a ventilator will die.^[47] In regions of the world without advanced health care systems, pneumonia is even more deadly. Limited access to clinics and hospitals, limited access to x-rays, limited antibiotic choices, and inability to diagnose and treat underlying conditions inevitably lead to higher rates of death from pneumonia. For these reasons, the majority of deaths in children under five due to pneumococcal disease occur in developing countries.^[48]

Adenovirus can cause severe necrotizing pneumonia in which all or part of a lung has increased translucency radiographically, which is called Swyer-James Syndrome.^[49] Severe adenovirus pneumonia also may result in bronchiolitis obliterans, a subacute inflammatory process in which the small airways are replaced by scar tissue, resulting in a reduction in lung volume and lung compliance.^[49] Sometimes pneumonia can lead to additional complications. Complications are more frequently associated with bacterial pneumonia than with viral pneumonia. The most important complications include respiratory and circulatory failure and pleural effusions, empyema or abscesses.

Clinical prediction rules

Clinical prediction rules have been developed to more objectively prognosticate outcomes in pneumonia. Although these rules are often used in deciding whether or not to hospitalize the person, they were derived simply to inform on prognosis; neither index was designed or tested as guide to determine whether the person would benefit by hospital admission.

• Pneumonia severity index (or PORT Score)^[50] – online calculator
• CURB-65 score, which takes into account the severity of symptoms, any underlying diseases, and age^[51] – online calculator

Pleural effusion, empyema, and abscess

A pleural effusion as seen on chest x-ray. The A arrow indicates fluid layering in the right chest. The B arrow indicates the width of the right lung. The volume of the lung is reduced because of the collection of fluid around the lung.

In pneumonia, a collection of fluid (pleural effusion) often forms in the space that surrounds the lung (the pleural cavity). Occasionally, microorganisms will infect this fluid, causing what is called an empyema. To distinguish an empyema from the more common simple parapneumonic effusion, the fluid is collected with a needle (thoracentesis), and examined. If this shows evidence of empyema, complete drainage of the fluid may be necessary, often requiring a chest tube. In severe cases of empyema, surgery may be needed. If the infected fluid is not drained, the infection may persist, because antibiotics do not penetrate well into the pleural cavity. If the fluid is sterile, it need be drained only if it is causing symptoms or remains unresolved.

Rarely, bacteria in the lung will form a pocket of infected fluid called a lung abscess. Lung abscesses can usually be seen with a chest X-ray or chest CT scan. Abscesses typically occur in aspiration pneumonia, and often contain several types of bacteria. Antibiotics are usually adequate to treat a lung abscess, but sometimes the abscess must be drained by a surgeon or radiologist.

Respiratory and circulatory failure

Because pneumonia affects the lungs, people with pneumonia often have difficulty breathing, sometimes to the point where mechanical assistance is required. Non-invasive breathing assistance may be helpful, such as with a bi-level positive airway pressure machine. In other cases, placement of an endotracheal tube (breathing tube) may be necessary, and a ventilator may be used to help the person breathe.

Pneumonia can also cause respiratory failure by triggering acute respiratory distress syndrome (ARDS), which results from a combination of infection and inflammatory response. The lungs quickly fill with fluid and become very stiff. This stiffness, combined with severe difficulties extracting oxygen due to the alveolar fluid, creates a need for mechanical ventilation.

Sepsis and septic shock are potential complications of pneumonia. Sepsis occurs when microorganisms enter the bloodstream and the immune system responds by secreting cytokines. Sepsis most often occurs with bacterial pneumonia; Streptococcus pneumoniae is the most common cause. Individuals with sepsis or septic shock need hospitalization in an intensive care unit. They often require intravenous fluids and medications to help keep their blood pressure up. Sepsis can cause liver, kidney, and heart damage, among other problems, and it is often fatal.

Epidemiology

Main article: Epidemiology of pneumonia

Age-standardized death from lower respiratory tract infections per 100,000 inhabitants in 2004.^[52]

no data   <100   100-700   700-1400   1400-2100   2100-2800   2800-3500

3500-4200   4200-4900   4900-5600   5600-6300   6300-7000   >7000

Pneumonia is a common illness affecting approximately 450 million people a year and occurring in all parts of the world.^[15] It is a major cause of death among all age groups resulting in 4 million deaths (7% of the world's yearly total).^[39][15] Rates are greatest in children less than five, and adults older than 75 years of age.^[15] It occurs about five times more frequently in the developing world versus the developed world.^[15] Viral pneumonia accounts for about 200 million cases.^[15]

Children

In 2008 pneumonia occurred in approximately 156 million children (151 million in the developing world and 5 million in the developed world).^[15] It resulted in 1.6 million deaths, or 28–34% of all deaths in those under five years of age, of which 95% occurred in the developing world.^[15][11] Countries with the greatest burden of disease include: India (43 million), China (21 million) and Pakistan (10 million).^[53] It is the leading cause of death among children in low income countries.^[39][15] Many of these deaths occur in the newborn period. The World Health Organization estimates that one in three newborn infant deaths are due to pneumonia.^[54] Approximately half of these deaths are theoretically preventable, as they are caused by the bacteria for which an effective vaccine is available.^[55]

History

WPA poster, 1936/1937

Pneumonia has been a common disease throughout human history.^[56] The symptoms were described by Hippocrates (c. 460 BC – 370 BC):^[56] "Peripneumonia, and pleuritic affections, are to be thus observed: If the fever be acute, and if there be pains on either side, or in both, and if expiration be if cough be present, and the sputa expectorated be of a blond or livid color, or likewise thin, frothy, and florid, or having any other character different from the common... When pneumonia is at its height, the case is beyond remedy if he is not purged, and it is bad if he has dyspnoea, and urine that is thin and acrid, and if sweats come out about the neck and head, for such sweats are bad, as proceeding from the suffocation, rales, and the violence of the disease which is obtaining the upper hand."^[57] However, Hippocrates referred to pneumonia as a disease "named by the ancients." He also reported the results of surgical drainage of empyemas. Maimonides (1135–1204 AD) observed "The basic symptoms that occur in pneumonia and that are never lacking are as follows: acute fever, sticking [pleuritic] pain in the side, short rapid breaths, serrated pulse and cough."^[58] This clinical description is quite similar to those found in modern textbooks, and it reflected the extent of medical knowledge through the Middle Ages into the 19th century.

Bacteria were first seen in the airways of individuals who died from pneumonia by Edwin Klebs in 1875.^[59] Initial work identifying the two common bacterial causes Streptococcus pneumoniae and Klebsiella pneumoniae was performed by Carl Friedländer^[60] and Albert Fränkel^[61] in 1882 and 1884, respectively. Friedländer's initial work introduced the Gram stain, a fundamental laboratory test still used today to identify and categorize bacteria. Christian Gram's paper describing the procedure in 1884 helped differentiate the two different bacteria, and showed that pneumonia could be caused by more than one microorganism.^[62]

Sir William Osler, known as "the father of modern medicine," appreciated the death and disability cause by pneumonia, describing it as the "captain of the men of death" in 1918, as it had overtaken tuberculosis as one of the leading causes of death in this time. This phrase was originally coined by John Bunyan in reference to "consumption" (tuberculosis).^[63][64] Osler also described pneumonia as "the old man's friend" as death was often quick and painless when there were many slower more painful ways to die.^[16]

Several developments in the 1900s improved the outcome for those with pneumonia. With the advent of penicillin and other antibiotics, modern surgical techniques, and intensive care in the twentieth century, mortality from pneumonia, which had approached 30%, dropped precipitously in the developed world. Vaccination of infants against Haemophilus influenzae type B began in 1988 and led to a dramatic decline in cases shortly thereafter.^[65] Vaccination against Streptococcus pneumoniae in adults began in 1977, and in children in 2000, resulting in a similar decline.^[66]

Society and culture

See also: List of pneumonia victims

Because of the combination of a very high burden of disease in developing countries and a relatively low awareness of the disease in industrialized countries, the global health community has declared November 12 to be World Pneumonia Day, a day for concerned citizens and policy makers to take action against the disease.^[67]

References

1. ^ ^{a b} McLuckie, [editor] A. (2009). Respiratory disease and its management. New York: Springer. p. 51. ISBN 9781848820944. 
2. ^ Leach, Richard E. (2009). Acute and Critical Care Medicine at a Glance (2 ed.). Wiley-Blackwell. ISBN 1-4051-6139-6. http://books.google.co.uk/books?id=7u_wu5VCsVQC&pg=PT168. Retrieved 2011-04-21. 
3. ^ Jeffrey C. Pommerville (2010). Alcamo's Fundamentals of Microbiology (9 ed.). Sudbury, Mass: Jones & Bartlett Publishers. p. 323. ISBN 0-7637-6258-X. http://books.google.co.uk/books?id=RJNQwQB8IxIC&pg=PA323. 
4. ^ Ashby, Bonnie; Turkington, Carol (2007). The encyclopedia of infectious diseases (3 ed.). New York: Facts on File. p. 242. ISBN 0-8160-6397-4. http://books.google.co.uk/books?id=4Xlyaipv3dIC&pg=PA242. Retrieved 2011-04-21. 
5. ^ "Causes of death in neonates and children under five in the world (2004)". World Health Organization.. 2008. http://www.who.int/entity/child_adolescent_health/media/causes_death_u5_neonates_2004.pdf. 
6. ^ Stedman's medical dictionary. (28th ed.). Philadelphia: Lippincott Williams & Wilkins. 2006. ISBN 9780781764506. 
7. ^ ^{a b c d e f g h i} Sharma, S; Maycher, B, Eschun, G (2007 May). "Radiological imaging in pneumonia: recent innovations". Current opinion in pulmonary medicine 13 (3): 159–69. doi:10.1097/MCP.0b013e3280f3bff4. PMID 17414122. 
8. ^ Dunn, L (2005 Jun 29-Jul 5). "Pneumonia: classification, diagnosis and nursing management". Nursing standard (Royal College of Nursing (Great Britain) : 1987) 19 (42): 50–4. PMID 16013205. 
9. ^ organization, World health (2005). Pocket book of hospital care for children : guidelines for the management of common illnesses with limited resources.. Geneva: World Health Organization. p. 72. ISBN 9789241546706. http://books.google.com/books?id=xbkbRG5XYxsC&pg=PA72. 
10. ^ ^{a b c d e f} Hoare Z; Lim WS (2006). "Pneumonia: update on diagnosis and management". BMJ 332 (7549): 1077–9. doi:10.1136/bmj.332.7549.1077. PMC 1458569. PMID 16675815. http://www.bmj.com/content/332/7549/1077.full.pdf. 
11. ^ ^{a b c d e f g h i j k l} Singh, V; Aneja, S (2011 Mar). "Pneumonia - management in the developing world". Paediatric respiratory reviews 12 (1): 52–9. doi:10.1016/j.prrv.2010.09.011. PMID 21172676. 
12. ^ ^{a b} Tintinalli, Judith E. (2010). Emergency Medicine: A Comprehensive Study Guide (Emergency Medicine (Tintinalli)). New York: McGraw-Hill Companies. pp. 480. ISBN 0-07-148480-9. 
13. ^ Darby, J; Buising, K (2008 Oct). "Could it be Legionella?". Australian family physician 37 (10): 812–5. PMID 19002299. 
14. ^ Ortqvist, A; Hedlund, J, Kalin, M (2005 Dec). "Streptococcus pneumoniae: epidemiology, risk factors, and clinical features". Seminars in respiratory and critical care medicine 26 (6): 563–74. doi:10.1055/s-2005-925523. PMID 16388428. 
15. ^ ^{a b c d e f g h i j k l m n o p q r s t u v w x} Ruuskanen, O; Lahti, E, Jennings, LC, Murdoch, DR (2011 Apr 9). "Viral pneumonia". Lancet 377 (9773): 1264–75. doi:10.1016/S0140-6736(10)61459-6. PMID 21435708. 
16. ^ ^{a b c d e f g h i} Ebby, Orin (Dec 2005). "Community-Acquired Pneumonia: From Common Pathogens To Emerging Resistance". Emergency Medicine Practice 7 (12). https://www.ebmedicine.net/topics.php?paction=showTopic&topic_id=118. 
17. ^ Lowe, J. F.; Stevens, Alan (2000). Pathology (2 ed.). St. Louis: Mosby. p. 197. ISBN 0-7234-3200-7. http://books.google.co.uk/books?id=AfVxLi4QTZQC&pg=PA197. 
18. ^ Snydman, editors, Raleigh A. Bowden, Per Ljungman, David R. (2010). Transplant infections (3rd ed.). Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. p. 187. ISBN 9781582558202. http://books.google.com/books?id=NWa4FJv-eBYC&pg=PA447. 
19. ^ ^{a b c} Anevlavis S; Bouros D (February 2010). "Community acquired bacterial pneumonia". Expert Opin Pharmacother 11 (3): 361–74. doi:10.1517/14656560903508770. PMID 20085502. 
20. ^ ^{a b c d e} Figueiredo LT (September 2009). "Viral pneumonia: epidemiological, clinical, pathophysiological and therapeutic aspects". J Bras Pneumol 35 (9): 899–906. PMID 19820817. 
21. ^ Clinical infectious diseases : a practical approach. New York, NY [u.a.]: Oxford Univ. Press. 1999. p. 833. ISBN 9780195081039. http://books.google.com/books?id=zvCOpighJggC&pg=PA833. 
22. ^ Diffuse parenchymal lung disease : ... 47 tables ([Online-Ausg.] ed.). Basel: Karger. 2007. p. 4. ISBN 9783805581530. 
23. ^ ^{a b} Ranganathan, SC; Sonnappa, S (2009 Feb). "Pneumonia and other respiratory infections". Pediatric clinics of North America 56 (1): 135–56, xi. doi:10.1016/j.pcl.2008.10.005. PMID 19135585. 
24. ^ ^{a b} Lynch, T; Bialy, L, Kellner, JD, Osmond, MH, Klassen, TP, Durec, T, Leicht, R, Johnson, DW (2010 Aug 6). Huicho, Luis. ed. "A systematic review on the diagnosis of pediatric bacterial pneumonia: when gold is bronze". PloS one 5 (8): e11989. doi:10.1371/journal.pone.0011989. PMC 2917358. PMID 20700510. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2917358. 
25. ^ ^{a b} Ezzati, edited by Majid; Lopez, Alan D., Rodgers, Anthony, Murray, Christopher J.L. (2004). Comparative quantification of health risks. Genève: Organisation mondiale de la santé. p. 70. ISBN 9789241580311. http://books.google.com/books?id=ACV1jEGx4AgC&pg=PA70. 
26. ^ ^{a b c d e f g h i j k l m n} Lim, WS; Baudouin, SV, George, RC, Hill, AT, Jamieson, C, Le Jeune, I, Macfarlane, JT, Read, RC, Roberts, HJ, Levy, ML, Wani, M, Woodhead, MA, Pneumonia Guidelines Committee of the BTS Standards of Care, Committee (2009 Oct). "BTS guidelines for the management of community acquired pneumonia in adults: update 2009". Thorax 64 Suppl 3: iii1–55. doi:10.1136/thx.2009.121434. PMID 19783532. 
27. ^ Saldías, F; Méndez, JI, Ramírez, D, Díaz, O (2007 Apr). "[Predictive value of history and physical examination for the diagnosis of community-acquired pneumonia in adults: a literature review]". Revista medica de Chile 135 (4): 517–28. PMID 17554463. 
28. ^ ^{a b} Call, SA; Vollenweider, MA, Hornung, CA, Simel, DL, McKinney, WP (2005 Feb 23). "Does this patient have influenza?". JAMA : the journal of the American Medical Association 293 (8): 987–97. doi:10.1001/jama.293.8.987. PMID 15728170. 
29. ^ Pediatric Primary Care: Ill-Child Care, Raymond C. Baker, Ch.19, page 99, LWW, 2001
30. ^ Pneumocystis Carinii Pneumonia Imaging, Author: Ali Nawaz Khan, MBBS, FRCS, FRCP, FRCR; Chief Editor: Eugene C Lin, MD; http://emedicine.medscape.com/article/359972-overview#showall
31. ^ Jefferson, T; Di Pietrantonj, C, Rivetti, A, Bawazeer, GA, Al-Ansary, LA, Ferroni, E (2010 Jul 7). Jefferson, Tom. ed. "Vaccines for preventing influenza in healthy adults". Cochrane database of systematic reviews (Online) (7): CD001269. doi:10.1002/14651858.CD001269.pub4. PMID 20614424. 
32. ^ "Seasonal Influenza (Flu)". Center for Disease Control and Prevention. http://www.cdc.gov/flu/. Retrieved 29 June 2011. 
33. ^ Jefferson T; Deeks JJ, Demicheli V, Rivetti D, Rudin M (2004). Jefferson, Tom. ed. "Amantadine and rimantadine for preventing and treating influenza A in adults". Cochrane Database Syst Rev (3): CD001169. doi:10.1002/14651858.CD001169.pub2. PMID 15266442. 
34. ^ Hayden FG; Atmar RL, Schilling M, et al. (October 1999). "Use of the selective oral neuraminidase inhibitor oseltamivir to prevent influenza" (PDF). N. Engl. J. Med. 341 (18): 1336–43. doi:10.1056/NEJM199910283411802. PMID 10536125. http://www.nejm.org/doi/pdf/10.1056/NEJM199910283411802. 
35. ^ Moberley, SA; Holden, J, Tatham, DP, Andrews, RM (2008 Jan 23). Andrews, Ross M. ed. "Vaccines for preventing pneumococcal infection in adults". Cochrane database of systematic reviews (Online) (1): CD000422. doi:10.1002/14651858.CD000422.pub2. PMID 18253977. 
36. ^ ^{a b} Bradley, JS; Byington, CL, Shah, SS, Alverson, B, Carter, ER, Harrison, C, Kaplan, SL, Mace, SE, McCracken GH, Jr, Moore, MR, St Peter, SD, Stockwell, JA, Swanson, JT (2011 Aug 31). "The Management of Community-Acquired Pneumonia in Infants and Children Older Than 3 Months of Age: Clinical Practice Guidelines by the Pediatric Infectious Diseases Society and the Infectious Diseases Society of America". Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 53 (7): e25–76. doi:10.1093/cid/cir531. PMID 21880587. 
37. ^ Yang, M; Yuping, Y, Yin, X, Wang, BY, Wu, T, Liu, GJ, Dong, BR (2010 Feb 17). Dong, Bi Rong. ed. "Chest physiotherapy for pneumonia in adults". Cochrane database of systematic reviews (Online) (2): CD006338. doi:10.1002/14651858.CD006338.pub2. PMID 20166082. 
38. ^ Chang CC; Cheng AC, Chang AB (2007). Chang, Christina C. ed. "Over-the-counter (OTC) medications to reduce cough as an adjunct to antibiotics for acute pneumonia in children and adults". Cochrane Database Syst Rev (4): CD006088. doi:10.1002/14651858.CD006088.pub2. PMID 17943884. 
39. ^ ^{a b c} Kabra SK; Lodha R, Pandey RM (2010). Kabra, Sushil K. ed. "Antibiotics for community-acquired pneumonia in children". Cochrane Database Syst Rev 3 (3): CD004874. doi:10.1002/14651858.CD004874.pub3. PMID 20238334. 
40. ^ Lutfiyya MN; Henley E, Chang LF, Reyburn SW (February 2006). "Diagnosis and treatment of community-acquired pneumonia". Am Fam Physician 73 (3): 442–50. PMID 16477891. http://www.aafp.org/afp/2006/0201/p442.pdf. 
41. ^ Scalera NM; File TM (April 2007). "How long should we treat community-acquired pneumonia?". Curr. Opin. Infect. Dis. 20 (2): 177–81. doi:10.1097/QCO.0b013e3280555072. PMID 17496577. 
42. ^ American Thoracic Society; Infectious Diseases Society of America (February 2005). "Guidelines for the management of adults with hospital-acquired, ventilator-associated, and healthcare-associated pneumonia". Am J Respir Crit Care Med 171 (4): 388–416. doi:10.1164/rccm.200405-644ST. PMID 15699079. 
43. ^ Marik, PE (2011 May). "Pulmonary aspiration syndromes". Current opinion in pulmonary medicine 17 (3): 148–54. doi:10.1097/MCP.0b013e32834397d6. PMID 21311332. 
44. ^ ^{a b} O'Connor S (2003). "Aspiration pneumonia and pneumonitis". Australian Prescriber 26 (1): 14–7. http://www.australianprescriber.com/magazine/26/1/14/7. 
45. ^ ^{a b c} Pneumonia, Bacterial at eMedicine, specifically, "The chest radiograph usually clears within 4 weeks in patients younger than 50 years without underlying pulmonary disease". Symptoms are often resolved within 1–2 weeks,
46. ^ Mufson, MA; RJ Stanek (1999-07-26). "Bacteremic pneumococcal pneumonia in one American City: a 20-year longitudinal study, 1978–1997". Am J Med (Department of Medicine, Marshall University School of Medicine) 107 (1A): 34S–43S. doi:10.1016/S0002-9343(99)00098-4. PMID 10451007. 
47. ^ Combes A; Luyt CE, Fagon JY, et al. (October 2004). "Impact of methicillin resistance on outcome of Staphylococcus aureus ventilator-associated pneumonia". Am. J. Respir. Crit. Care Med. 170 (7): 786–92. doi:10.1164/rccm.200403-346OC. PMID 15242840. 
48. ^ World Health Organization. Acute Respiratory Infections: Streptococcus pneumoniae.
49. ^ ^{a b} Kliegman, Robert; Richard M Kliegman (2006). Nelson essentials of pediatrics. St. Louis, Mo: Elsevier Saunders. ISBN 0-8089-2325-0. 
50. ^ Fine MJ; Auble TE, Yealy DM, et al. (January 1997). "A prediction rule to identify low-risk patients with community-acquired pneumonia" (PDF). N. Engl. J. Med. 336 (4): 243–50. doi:10.1056/NEJM199701233360402. PMID 8995086. http://www.nejm.org/doi/pdf/10.1056/NEJM199701233360402. 
51. ^ Lim WS; van der Eerden MM, Laing R, et al. (2003). "Defining community acquired pneumonia severity on presentation to hospital: an international derivation and validation study". Thorax 58 (5): 377–82. doi:10.1136/thorax.58.5.377. PMC 1746657. PMID 12728155. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1746657. 
52. ^ "WHO Disease and injury country estimates". World Health Organization (WHO). 2004. http://www.who.int/healthinfo/global_burden_disease/estimates_country/en/index.html. Retrieved 11 November 2009. 
53. ^ Rudan, I; Boschi-Pinto, C, Biloglav, Z, Mulholland, K, Campbell, H (2008 May). "Epidemiology and etiology of childhood pneumonia". Bulletin of the World Health Organization 86 (5): 408–16. doi:10.2471/BLT.07.048769. PMC 2647437. PMID 18545744. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2647437. 
54. ^ Garenne M; Ronsmans C, Campbell H (1992). "The magnitude of mortality from acute respiratory infections in children under 5 years in developing countries". World Health Stat Q 45 (2–3): 180–91. PMID 1462653. 
55. ^ WHO (1999). "Pneumococcal vaccines. WHO position paper". Wkly. Epidemiol. Rec. 74 (23): 177–83. PMID 10437429. 
56. ^ ^{a b} al.], Ralph D. Feigin ... [et (2003). Textbook of pediatric infectious diseases (5th ed.). Philadelphia: W. B. Saunders. p. 299. ISBN 9780721693293. http://books.google.com/books?id=G6k0tpPMRsIC&pg=PA299. 
57. ^ Hippocrates On Acute Diseases wikisource link
58. ^ Maimonides, Fusul Musa ("Pirkei Moshe").
59. ^ Klebs E (1875-12-10). "Beiträge zur Kenntniss der pathogenen Schistomyceten. VII Die Monadinen". Arch. Exptl. Pathol. Parmakol. 4 (5/6): 40–488. 
60. ^ Friedländer C (1882-02-04). "Über die Schizomyceten bei der acuten fibrösen Pneumonie". Virchow's Arch pathol. Anat. U. Physiol. 87 (2): 319–324. doi:10.1007/BF01880516. 
61. ^ Fraenkel A (1884-04-21). "Über die genuine Pneumonie, Verhandlungen des Congress für innere Medicin". Dritter Congress 3: 17–31. 
62. ^ Gram C (1884-03-15). "Über die isolierte Färbung der Schizomyceten in Schnitt- und Trocken-präparaten". Fortschr. Med 2 (6): 185–9. 
63. ^ al.], edited by J.F. Tomashefski, Jr ... [et (2008). Dail and Hammar's pulmonary pathology. (3. ed.). New York: Springer. p. 228. ISBN 9780387983950. http://books.google.com/books?id=j-eYLc1BA3oC&pg=PA228. 
64. ^ William Osler, Thomas McCrae (1920). The principles and practice of medicine: designed for the use of practitioners and students of medicine (9th ed.). D. Appleton. p. 78. "One of the most widespread and fatal of all acute diseases, pneumonia has become the "Captain of the Men of Death," to use the phrase applied by John Bunyan to consumption." 
65. ^ Adams WG; Deaver KA, Cochi SL, et al. (January 1993). "Decline of childhood Haemophilus influenzae type B (Hib) disease in the Hib vaccine era". JAMA 269 (2): 221–6. doi:10.1001/jama.269.2.221. PMID 8417239. 
66. ^ Whitney CG; Farley MM, Hadler J, et al. (May 2003). "Decline in invasive pneumococcal disease after the introduction of protein-polysaccharide conjugate vaccine". N. Engl. J. Med. 348 (18): 1737–46. doi:10.1056/NEJMoa022823. PMID 12724479. 
67. ^ "World Pneumonia Day Official Website". World Pneumonia Day Official Website. Fiinex. http://worldpneumoniaday.org/. Retrieved 13 August 2011. 

v d e Pathology: Medical conditions and ICD code (Disease / Disorder / Illness, Syndrome / Sequence, Symptom / Sign, Injury, etc.) (A/B, 001–139) Infectious disease/Infection: Bacterial disease (G+, G-) · Virus disease · Parasitic disease (Protozoan infection, Helminthiasis, Ectoparasitic infestation) · Mycosis · Zoonosis (C/D, 140–239 & 279–289) Cancer (C00–D48, 140–239) Tumor Myeloid hematologic (D50–D77, 280–289) Anemia · Coagulopathy Lymphoid immune (D80–D89, 279) Immunodeficiency · Immunoproliferative disorder · Hypersensitivity (E, 240–278) Endocrine disease · Nutrition disorder · Inborn error of metabolism (F, 290–319) Mental disorder (G, 320–359) Nervous system disease (CNS, PNS) · Neuromuscular disease (H, 360–389) Eye disease · Ear disease (I, 390–459) Cardiovascular disease (Heart disease, Vascular disease) (J, 460–519) Respiratory disease (Obstructive lung disease, Restrictive lung disease, Pneumonia) (K, 520–579) Stomatognathic disease (Tooth disease) · Digestive disease (Esophageal, Stomach, Enteropathy, Liver, Pancreatic) (L, 680–709) Skin disease · skin appendages (Nail disease, Hair disease, Sweat gland disease) (M, 710–739) Musculoskeletal disorders: Myopathy · Arthropathy · Osteochondropathy (Osteopathy, Chondropathy) (N, 580–629) Urologic disease (Nephropathy, Urinary bladder disease) · Male genital disease · Breast disease · Female genital disease (O, 630–679) Complications of pregnancy · Obstetric labor complication · Puerperal disorder (P, 760–779) Fetal disease (Q, 740–759) Congenital disorder (Congenital abnormality) (R, 780–799) Syndromes · Medical signs (Eponymous) (S/T, 800–999) Bone fracture · Joint dislocation · Sprain · Strain · Subluxation · Head injury · Chest trauma · Poisoning

v d e Pathology of respiratory system (J, 460–519), respiratory diseases Upper RT (including URTIs, Common cold) Head sinuses: Sinusitis nose: Rhinitis (Vasomotor rhinitis, Atrophic rhinitis, Hay fever) · Nasal polyp · Rhinorrhea · nasal septum (Nasal septum deviation, Nasal septum perforation, Nasal septal hematoma) tonsil: Tonsillitis · Adenoid hypertrophy · Peritonsillar abscess Neck pharynx: Pharyngitis (Strep throat) · Laryngopharyngeal reflux (LPR) · Retropharyngeal abscess larynx: Croup · Laryngitis · Laryngopharyngeal reflux (LPR) · Laryngospasm vocal folds: Laryngopharyngeal reflux (LPR) · Vocal fold nodule · Vocal cord paresis · Vocal cord dysfunction epiglottis: Epiglottitis trachea: Tracheitis · Tracheal stenosis Lower RT/lung disease (including LRTIs) Bronchial/ obstructive acute: Acute bronchitis chronic: COPD (Chronic bronchitis, Acute exacerbations of chronic bronchitis, Acute exacerbation of COPD, Emphysema) · Asthma (Status asthmaticus, Aspirin-induced, Exercise-induced) · Bronchiectasis unspecified: Bronchitis · Bronchiolitis (Bronchiolitis obliterans) · Diffuse panbronchiolitis Interstitial/ restrictive (fibrosis) External agents/ occupational lung disease Pneumoconiosis (Asbestosis, Baritosis, Bauxite fibrosis, Berylliosis, Caplan's syndrome, Chalicosis, Coalworker's pneumoconiosis, Siderosis, Silicosis, Talcosis, Byssinosis) Hypersensitivity pneumonitis (Bagassosis, Bird fancier's lung, Farmer's lung, Lycoperdonosis) Other ARDS · Pulmonary edema · Löffler's syndrome/Eosinophilic pneumonia · Respiratory hypersensitivity (Allergic bronchopulmonary aspergillosis) Hamman-Rich syndrome · Idiopathic pulmonary fibrosis · Sarcoidosis Obstructive or restrictive Pneumonia/ pneumonitis By pathogen Viral · Bacterial (Pneumococcal, Klebsiella) / Atypical bacterial (Mycoplasma, Legionnaires' disease, Chlamydiae) · Fungal (Pneumocystis) · Parasitic · noninfectious (Chemical/Mendelson's syndrome, Aspiration/Lipid) By vector/route Community-acquired · Healthcare-associated · Hospital-acquired By distribution Broncho- · Lobar IIP UIP · DIP · BOOP-COP · NSIP · RB Other Atelectasis · circulatory (Pulmonary hypertension, Pulmonary embolism) · Lung abscess Pleural cavity/ mediastinum Pleural disease Pleuritis/pleurisy Pneumothorax/Hemopneumothorax Pleural effusion: Hemothorax · Hydrothorax · Chylothorax · Empyema/pyothorax · Malignant Fibrothorax Mediastinal disease Mediastinitis · Mediastinal emphysema Other/general Respiratory failure · Influenza · SARS · Idiopathic pulmonary haemosiderosis · Pulmonary alveolar proteinosis M: RES anat(n, x, l, c)/phys/devp noco(c, p)/cong/tumr, sysi/epon, injr proc, drug(R1/2/3/5/6/7)

v d e Pneumonia Infectious pneumonias Bacterial pneumonia · Viral pneumonia · Fungal pneumonia · Parasitic pneumonia · Atypical pneumonia · Community-acquired pneumonia · Healthcare-associated pneumonia · Hospital-acquired pneumonia · Ventilator-associated pneumonia · Severe acute respiratory syndrome Pneumonias caused by infectious or noninfectious agents Aspiration pneumonia · Lipid pneumonia · Eosinophilic pneumonia · Bronchiolitis obliterans organizing pneumonia Noninfectious pneumonia Chemical pneumonia M: RES anat(n, x, l, c)/phys/devp noco(c, p)/cong/tumr, sysi/epon, injr proc, drug(R1/2/3/5/6/7)

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Dansk (Danish)
n. - lungebetændelse

Nederlands (Dutch)
longontsteking

Français (French)
n. - pneumonie

Deutsch (German)
n. - Lungenentzündung, Pneumonie

Ελληνική (Greek)
n. - (παθολ.) πνευμονία

Italiano (Italian)
polmonite

Português (Portuguese)
n. - pneumonia (f) (Med.)

Русский (Russian)
пневмония, воспаление легких

Español (Spanish)
n. - pulmonía, neumonía

Svenska (Swedish)
n. - lunginflammation

中文（简体）(Chinese (Simplified))
肺炎

中文（繁體）(Chinese (Traditional))
n. - 肺炎

한국어 (Korean)
n. - 폐렴

日本語 (Japanese)
n. - 肺炎

العربيه (Arabic)
‏(الاسم) ذات الرئه, ذات الجنب, إلتهاب رئوي‏

עברית (Hebrew)
n. - ‮דלקת ריאות‬

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