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Pneumonia fills the lung's alveoli with fluid, keeping oxygen from reaching the bloodstream. The alveolus on the left is normal, while the alveolus on the right is full of fluid from pneumonia.
Pneumonia fills the lung's alveoli with fluid, keeping oxygen from reaching the bloodstream. The alveolus on the left is normal, while the alveolus on the right is full of fluid from pneumonia.

Pneumonia is an illness in which the small, air-filled sacs in the lungs (alveoli) responsible for absorbing oxygen from the atmosphere are flooded with fluid. Pneumonia can result from a variety of causes, including infection with bacteria, viruses, fungi, or parasites. Pneumonia may also result from chemical or physical irritation of the lungs.

Symptoms associated with pneumonia include cough, chest pain, fever, and difficulty breathing. Diagnostic tools include X-rays and examination of the sputum. Treatment depends on the cause of pneumonia; bacterial pneumonia is treated with antibiotics.

Pneumonia is a common illness, occurs in all age groups, and is a leading cause of death among the elderly and people who are chronically ill. Vaccines to prevent certain types of pneumonia are available. The prognosis for an individual depends on the type of pneumonia, the correct treatment, any complications, and his or her underlying health. Pneumonia may occur as the result of another medical illness, such as lung cancer or alcohol abuse.



People with infectious pneumonia often have a cough that produces greenish or yellow sputum and a high fever that may be accompanied by shaking chills. Shortness of breath is also common, as is pleuritic chest pain, a sharp or stabbing pain, either felt or worse during deep breaths or coughs. People with pneumonia may cough up blood, experience headaches, or develop sweaty and clammy skin. Other symptoms may include loss of appetite, fatigue, blueness of the skin, nausea, vomiting, and joint pains or muscle aches. Less common forms of pneumonia can cause a variety of other symptoms. For instance, pneumonia caused by Legionella may cause abdominal pain and diarrhea, while pneumonia caused by tuberculosis or Pneumocystis may cause only weight loss and night sweats. In elderly people the manifestations of pneumonia may not be typical. Instead, they may develop new or worsening confusion or may experience unsteadiness leading to falls. Infants with pneumonia may have many of the symptoms above, but often they are simply sleepy or have decreased appetite.


To diagnose pneumonia, health care providers rely on a patient's symptoms and findings from physical examination. Information from chest x-rays, blood tests, and sputum cultures may also be helpful. The chest x-ray is typically used for diagnosis in hospitals and some clinics with x-ray facilities. However, in a community setting (general practice), pneumonia is usually diagnosed on the basis of symptoms and physical examination alone. Diagnosing pneumonia can be difficult in some people, especially those who have other illnesses. Occasionally a chest CT scan or other tests may be needed to distinguish pneumonia from other illnesses.

Physical examination

Individuals with symptoms of pneumonia need medical evaluation. Physical examination by a health care provider may reveal fever or sometimes low body temperature, an increased respiratory rate, low blood pressure, a fast heart rate, or a low amount of oxygen in the blood, as indicated by pulse oxymetry or blood gas analysis. People who are struggling to breathe, confused, or who have a blue-tinged skin require immediate attention.

Listening (auscultation) to the lungs with a stethoscope can reveal several things. A lack of normal breath sounds, the presence of crackling sounds (rales), or increased loudness of whispered speech (whispered pectoriloquy) can identify areas of the lung which are stiff and full of fluid (called "consolidation"). The examiner may also feel the way the chest expands (palpation) and tap the chest wall (percussion) to further localize consolidation. The examiner may also palpate for increased vibration of the chest when speaking (tactile fremitus). [1]

Chest X-rays, sputum cultures and other tests

Pneumonia as seen on chest x-ray.  A: Normal chest x-ray. B: Abnormal chest x-ray with shadowing from pneumonia in the right lung (left side of image).
Pneumonia as seen on chest x-ray. A: Normal chest x-ray. B: Abnormal chest x-ray with shadowing from pneumonia in the right lung (left side of image).

An important test for detecting pneumonia in unclear situations is a chest x-ray. Chest x-rays can reveal areas of opacity (seen as white) which represent consolidation. Although a normal chest x-ray makes pneumonia less likely, pneumonia is sometimes not seen on x-rays because the disease is either in its initial stages or because it involves a part of the lung not easily seen by x-ray. In some cases, chest CT (computed tomography) can reveal pneumonia which is not seen on chest x-ray. However, x-rays can be misleading, because other problems, like lung scarring and congestive heart failure, can mimic pneumonia on x-ray. [2] Chest x-rays are also used to evaluate for complications of pneumonia. (See below.)

If an individual is not getting better with antibiotics, or if the health care provider has concerns about the diagnosis, a culture of the person's sputum may be requested. Sputum cultures generally take at least two to three days, so they are mainly used to confirm that the infection is sensitive to an antibiotic that has already been started. A blood sample may similarly be cultured to look for infection in the blood (blood culture). Any bacteria identified are then tested to see which antibiotics will be most effective.

A complete blood count may show a high white blood cell count, indicating the presence of an infection or inflammation. In some people with immune system problems, the white blood cell count may appear deceptively normal. Blood tests may be used to evaluate kidney function (important when prescribing certain antibiotics) or to look for low blood sodium. Low blood sodium in pneumonia is thought to be due to extra anti-diuretic hormone produced when the lungs are diseased. Specific blood serology tests for other bacteria (Mycoplasma, Legionella and Chlamydophila) and a urine test for Legionella antigen are available. Respiratory secretions can also be tested for the presence of viruses such as influenza, respiratory syncytial virus, and adenovirus.

Causes of pneumonia

The bacteria Streptococcus pneumoniae, a common cause of pneumonia, photographed through a microscope
The bacteria Streptococcus pneumoniae, a common cause of pneumonia, photographed through a microscope

Although over one hundred microorganisms can cause pneumonia, only a few of them are responsible for most cases. The most common causes of pneumonia are viruses and several types of bacteria: Streptococcus pneumoniae, Gram-negative bacteria and "atypical" bacteria. The terms "Gram-positive" and "Gram-negative" refer to the bacteria's color (purple or red, respectively) when stained using a process called the Gram stain. Less common causes of pneumonia include fungi and irritants, as discussed below.

Streptococcus pneumoniae, often called "pneumococcus", is the most common bacterial cause of pneumonia in all age groups except newborn infants. This is a Gram-positive bacteria which often lives in the throats of people who do not have pneumonia. Another important Gram-positive cause of pneumonia is Staphylococcus aureus. Gram-negative bacteria cause pneumonia less frequently than gram-positive bacteria. Some of the gram-negative bacteria that cause pneumonia include Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Moraxella catarrhalis. These bacteria often live in the stomach or intestines and may enter the lungs if vomit is inhaled. The "atypical" bacteria which cause pneumonia include Chlamydophila pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila. They are called "atypical" because they commonly affect healthier people, may be less severe, and usually require different antibiotics than bacteria such as Streptococcus pneumoniae.

Viral pneumonia is commonly caused by viruses such as influenza virus, respiratory syncytial virus (RSV), adenovirus, and metapneumovirus. Herpes simplex virus is a rare cause of pneumonia except in newborns. Although viral pneumonia is usually less severe than bacterial pneumonia, it can damage the lungs and may allow bacteria to cause a more serious infection.

Fungi are uncommon causes of pneumonia which may occur in individuals with immune system problems due to AIDS, immunosuppresive drugs, or other medical problems. Fungal pneumonia is most often caused by Histoplasma capsulatum, Cryptococcus neoformans, and Coccidioides immitis. Histoplasmosis is most common in the Mississippi River basin and Coccidioides is most common in the southwestern United States. Other important causes of pneumonia in people with impaired immune systems include the fungus Pneumocystis jiroveci, the atypical bacterium Mycobacterium avium, and the virus cytomegalovirus (CMV).

Not all pneumonias are caused by infections. Eosinophilic pneumonia, chemical pneumonia, and bronchiolitis obliterans organizing pneumonia (BOOP) each have unique characteristics covered in their individual articles.

Types of pneumonia

There are many different ways to classify infectious pneumonia. Early scientists first classified pneumonias using the various anatomic changes visible in the lungs during autopsies. Later, as more became known about the microorganisms causing pneumonia, a microbiologic classification arose. With the advent of x-rays, a radiological classification was developed. Another important classification system used for pneumonia is the combined clinical classification. It combines many factors, including age, risk factors for certain microorganisms, the person's underlying health, and whether he or she has recently been hospitalized. Finally, there are classification systems for other types of pneumonia.

Anatomic classification

A lobar pneumonia is an infection that only involves a single lobe, or section, of a lung. Lobar pneumonia is often due to Streptococcus pneumoniae. Anatomic changes in the affected part of the lung can be seen during autopsy. Multilobar pneumonia involves more than one lobe, and it often is a more severe illness than lobar pneumonia. Interstitial pneumonia involves the areas in between the alveoli, and it may be called "interstitial pneumonitis." Interstitial pneumonia is more likely to be caused by viruses or by atypical bacteria.

Radiologic classification

The discovery of x-rays made it possible to determinine the anatomic type of pneumonia without direct examination of the lungs at autopsy. Early investigators distinguished between typical lobar pneumonia and atypical (e.g. Chlamydophila) or viral pneumonia using the location, distribution, and appearance of the opacities they saw on chest x-rays. Certain x-ray findings can be used to help predict the course of illness, although it is not possible to clearly determine the microbiologic cause of a pneumonia based on x-rays alone.

Microbiologic classification

Determining which microorganism is causing an individual's pneumonia is an important step in deciding treatment type and length. Sputum cultures, blood cultures, tests on respiratory secretions, and specific blood tests are used to determine the microbiologic classification. Because such laboratory testing typically takes several days, microbiologic classification is usually not possible at the time of initial diagnosis.

Combined clinical classification

The combined clinical classification attempts to identify all of a person's important risk factors when he or she first comes to medical attention. The goal of this classification scheme is to select appropriate initial treatments before the microbiologic cause of the disease is known. There are two broad categories of pneumonia in this scheme: Community acquired pneumonia and Hospital acquired pneumonia.

Community-acquired pneumonia

Main article:Community-acquired pneumonia.

Community-acquired pneumonia (CAP) is infectious pneumonia in a person who has not recently been hospitalized. CAP is the most common type of pneumonia, and it is the type experienced by most people who get pneumonia. The most common causes of CAP differ depending on a person's age, but they include Streptococcus pneumoniae, viruses, the atypical bacteria, and Haemophilus influenzae. Overall, Streptococcus pneumoniae is the most common cause of community-acquired pneumonia worldwide. Gram negative bacteria cause CAP in certain at-risk populations. CAP is the fourth most common cause of death in the United Kingdom and the sixth in the United States.

An outdated term, walking pneumonia, has been used to describe a type of community-acquired pneumonia that does not restrict a person's ability to walk. Walking pneumonia is usually caused by a virus or by atypical bacteria.

Hospital-acquired pneumonia

Hospital-acquired pneumonia, also called nosocomial pneumonia, is pneumonia acquired during or after hospitalization for another illness or procedure. The causes, microbiology, treatment and prognosis are different from community-acquired pneumonia. Up to 5% of patients admitted to a hospital for other causes subsequently develop pneumonia. Hospitalized patients may have many risk factors for pneumonia, including mechanical ventilation, prolonged malnutrition, underlying heart and lung diseases, decreased amounts of stomach acid, and immune disturbances. Additionally, the microorganisms a person is exposed to in a hospital are often different from those at home. Hospital-acquired microorganisms may include resistant bacteria such as MRSA, Pseudomonas, Enterobacter, and Serratia. Because individuals with hospital-acquired pneumonia usually have underlying illnesses and are exposed to more dangerous bacteria, it tends to be more deadly than community-acquired pneumonia.

Treatment for pneumonia should ideally be selected based on the causative microorganism and its known antibiotic sensitivity. However, a specific cause for pneumonia is identified in only 50% of people, even after extensive evaluation. Empiric treatment is usually started well before laboratory reports are available because such treatment generally cannot be delayed in any patient with a serious pneumonia. Antibiotics used for hospital-acquired pneumonia include vancomycin, third and fourth generation cephalosporins, carbapenems, fluoroquinolones, and aminoglycosides. Multiple antibiotics are usually administered in combination to cover all the possible causative organisms. Antibiotic choices vary from hospital to hospital because of differences in likely microrganisms and resistance patterns.

Ventilator-associated pneumonia (VAP) is a subset of hospital-acquired pneumonia. VAP is pneumonia which occurs after at least 48 hours of intubation and mechanical ventilation.

Other types of pneumonia

SARS is a highly contagious and deadly type of pneumonia which occurred in 2002 and 2003 after initial outbreaks in China. SARS is caused by the SARS coronavirus, a previously unknown pathogen. The last SARS case was seen in June 2003.
BOOP is caused by inflammation of the small airways of the lungs. It is also known as cryptogenic organizing pneumonitis (COP).
Eosinophilic pneumonia is invasion of the lung by eosinophils, a particular kind of white blood cell. Eosinophilic pneumonia often occurs in response to infection with a parasite or after exposure to certain types of environmental factors.
Also known as chemical pneumonitis, chemical pneumonia is caused by chemical toxins such as pesticides which enter the body by inhalation or by skin contact. When the toxic substance is an oil, the pneumonia may be called lipoid pneumonia.


Upper panel shows a normal lung under the microscope. The white spaces contain air. Bottom panel shows a lung with pneumonia under the microscope. Note that the white spaces are replaced by inflammation and debris
Upper panel shows a normal lung under the microscope. The white spaces contain air. Bottom panel shows a lung with pneumonia under the microscope. Note that the white spaces are replaced by inflammation and debris

The symptoms of infectious pneumonia are the result of both the invasion of the lungs by microorganisms and the immune system's response to the infection. The mechanisms of infection are quite different for viruses and the other microorganisms.


Main article: viral pneumonia

Viruses must invade cells in order to reproduce. Typically, a virus reaches the lungs by traveling in droplets through the mouth and nose with inhalation. There, the virus invades the cells lining the airways and the alveoli. This invasion often leads to cell death either through direct killing by the virus or by self-destruction (apoptosis). Further damage to the lungs occurs when the immune system responds to the infection. White blood cells, in particular lymphocytes, are responsible for activating a variety of chemicals (cytokines) which cause leaking of fluid into the alveoli. The combination of cellular destruction and fluid-filled alveoli interrupts the transportation of oxygen into the bloodstream.

In addition to the effects on the lungs, many viruses affect other organs and can lead to illness disrupting many different bodily functions. Viruses also make the body more susceptible to bacterial infection; for this reason, bacterial pneumonia often complicates viral pneumonia.

Bacteria and fungi

Main articles: bacterial pneumonia, fungal pneumonia

Bacteria and fungi also typically enter the lung with inhalation, though they can reach the lung through the bloodstream if other parts of the body are infected. Often, bacteria live in parts of the upper respiratory tract and are continually being inhaled into the alveoli. Once inside the alveoli, bacteria and fungi travel into the spaces between the cells and also between adjacent alveoli through connecting pores. This invasion triggers the immune system to respond by sending white blood cells responsible for attacking microorganisms (neutrophils) to the lungs. The neutrophils engulf and kill the offending organisms but also release cytokines which result in a general activation of the immune system. This results in the fever, chills, and fatigue common in bacterial and fungal pneumonia. The neutrophils, bacteria, and fluid leaked from surrounding blood vessels fill the alveoli and result in impaired oxygen transportation.

Bacteria often travel from the lung into the blood stream and can result in serious illness such as septic shock, in which there is low blood pressure leading to damage in multiple parts of the body including the brain, kidney, and heart. They can also travel to the area between the lungs and the chest wall, called the pleural cavity.


Main article: parasitic pneumonia

There are a variety of parasites which can affect the lungs. In general, these parasites enter the body through the skin or by being swallowed. Once inside the body, these parasites travel to the lungs, most often through the blood. There, a similar 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.


Most cases of pneumonia in young, otherwise healthy people can be treated at home. Typically, oral antibiotics, rest, fluids, and home care are sufficient for complete resolution. However, people who are having trouble breathing or have other lung problems may need more advanced treatment. If pneumonia does not improve with home treatment, symptoms get worse or signs of complications of pneumonia develop, the person will often have to be hospitalized.

Antibiotics are the treatment of choice for bacterial pneumonia. Antibiotics are not useful for viral pneumonias, but are sometimes used to prevent or treat associated bacterial infection when the lungs have been damaged by a viral infection. The antibiotic choice depends on the nature of the pneumonia, the microorganisms most commonly causing pneumonia in the geographical region, and the immune status and underlying health of the individual. In the United Kingdom, amoxicillin is used as first-line therapy in the vast majority of patients who acquire pneumonia in the community, sometimes with added clarithromycin. In North America, where the "atypical" forms of community-acquired pneumonia are becoming more common, clarithromycin, azithromycin, and the fluoroquinolones have displaced the amoxicillin as first-line therapy. In hospitalized individuals or those with immune deficiencies, local guidelines determine the selection of antibiotics. These antibiotics are typically given through an intravenous line.

People who have difficulty breathing due to pneumonia may require extra oxygen. Extremely sick individuals may require artificial ventilation and intensive care as life-saving measures while his or her immune system fights off the infectious cause with the help of antibiotics and other drugs. viral pneumonia caused by influenza A or B may be treated with rimantadine, amantadine, oseltamivir or zanamivir when individuals come to medical attention within 48 hours of the onset of symptoms. There is no known effective treatment for pneumonia caused by SARS coronavirus, adenovirus, hantavirus, or parainfluenza virus.


Complications are secondary conditions, symptoms, or other disorders that are caused by pneumonia. Complications are more frequently associated with bacterial infections than with viral infections. The most important complications include:

Circulatory and respiratory collapse

Sepsis can occur when microorganisms enter the blood stream 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 require hospitalization in an intensive care unit. They often require medications and intravenous fluids to keep their blood pressure from dropping too low. Sepsis can cause liver, kidney, and heart damage among other things and is associated with a high mortality.

Because pneumonia affects the lungs, often individuals with pneumonia have difficulty breathing. If enough of the lung is involved, it may not be possible for a person to breathe enough to live without support. Non-invasive machines such as a bilevel positive airway pressure machine may be used. Otherwise, placement of an endotracheal tube (breathing tube) into the mouth 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, create a need for mechanical ventilation.

Pleural effusion Chest x-ray of a pleural effusion. The arrow A shows fluid layering in the right pleural cavity. The B arrow shows the width of the lung
Pleural effusion Chest x-ray of a pleural effusion. The arrow A shows fluid layering in the right pleural cavity. The B arrow shows the width of the lung

Pleural effusion, empyema and abscess

Occasionally, microorganisms from the lung will cause fluid to form in the space surrounding the lung, called the pleural cavity. If the microorganisms themselves are present, the fluid collection is often called an empyema. If pleural fluid is present in a person with pneumonia, the fluid should be collected with a needle (thoracentesis) and examined. Depending on the result of the examination, complete drainage of the fluid may be necessary, often with a tube placed in the chest. In severe cases of empyema, surgery is often required to completely remove the fluid. If the fluid is not drained, bacteria can continue to cause illness because antibiotics do not penetrate well into the pleural cavity.

Rarely, microorganisms in the lung will form a pocket of fluid and bacteria called an abscess. Abscesses can be seen on an x-ray as a cavity within the lung. Abscesses typically occur in aspiration pneumonia and most often contain a mixture of anaerobic bacteria. Usually antibiotics are able to fully treat abscesses, but sometimes they must be drained by a surgeon or radiologist.

Prognosis and mortality

With treatment, most types of bacterial pneumonia can be cured within one to two weeks. Viral pneumonia may last longer. Mycoplasmal pneumonia may take four to six weeks to resolve completely.

The eventual outcome of an episode of pneumonia depends on how ill a person is when they first are diagnosed. One common way to predict outcome is the Pneumonia Severity Score which takes into account the severity of symptoms, any underlying disease and age.[3] This score can be helpful in deciding whether or not to hospitalize the patient.

In the United States, mortality from pneumococcal pneumonia is 1 in 20. In cases where the disease progresses to blood poisoning (bacteremia), 2 of 10 die. Mortality also depends on the underlying cause of the pneumonia. Pneumonia caused by Mycoplasma, for instance, is associated with little mortality. However, 50% of people who develop MRSA pneumonia while on a ventilator die.[4]


There are several ways to prevent infectious pneumonia. Treating underlying illness (such as AIDS) can decrease a person's risk. Smoking cessation is important not only for treatment of any underlying lung disease, but also because cigarette smoke interferes with many of the body's natural defenses against pneumonia.

Vaccination is important in both children and adults. Vaccinations against Haemophilus influenzae and Streptococcus pneumoniae in the first year of life have greatly reduced their role in pneumonia in children. Vaccination of children against Streptococcus pneumoniae has also led to a decreased incidence in adults because many adults acquire infection from children. A vaccine against Streptococcus pneumoniae is also available for adults and is currently recommended for all healthy individuals older than 65 and any adults with emphysema, congestive heart failure, diabetes mellitus, cirrhosis of the liver, alcoholism, cerebrospinal fluid leaks, or who do not have a spleen. A repeat vaccination may also be required after five or ten years.[5]

Influenza vaccines should be given yearly to the same individuals who receive vaccination against Streptococcus pneumoniae. In addition, health care workers, nursing home residents, and pregnant women should receive the vaccine.[6] When an influenza outbreak is occurring, medications such as amantadine, rimantadine, zanamivir, and oseltamivir have been shown to prevent cases of influenza.[7][8]


Pneumonia is a common illness in all parts of the world. It is a major cause of death among all age groups. In children, the majority of deaths occur in the newborn period, with over two million deaths a year worldwide. In fact, the WHO estimates that one in three newborn infant deaths are due to pneumonia.[9] Mortality decreases with age until late adulthood; elderly individuals are at particular risk for pneumonia and associated mortality.

More cases of pneumonia occur during winter months than during other times of the year. Pneumonia occurs more commonly in males than females and in blacks than Caucasians. Individuals with underlying illnesses such as Alzheimer's disease, cystic fibrosis, emphysema, tobacco smoking, alcoholism, or immune system problems are at increased risk for pneumonia.[10] These individuals are also more likely to have repeated episodes of pneumonia. People who are hospitalized for any reason are also at high risk for pneumonia.


Hippocrates: a conventionalized image in a Roman "portrait" bust (19th century engraving)
Hippocrates: a conventionalized image in a Roman "portrait" bust (19th century engraving)

The history of pneumonia closely parallels the the history of medicine itself. The symptoms of pneumonia were first described by Hippocrates (c. 460 BC–380 BC): "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."[11] Hippocrates himself refers to pneumonia as a disease "named by the ancients." Hippocrates also reports the results of surgical drainage of empyemas. Maimonides (1138-1204 AD) observed “The basic symptoms which occur in pneumonia and which are never lacking are as follows: acute fever, sticking [pleuritic] pain in the side, short rapid breaths, serrated pulse and cough."[12]

Bacteria were first seen in the airways of individuals who died of pneumonia by Edwin Klebs in 1875.[13] Initial work identifying the two common bacterial causes Streptococcus pneumoniae and Klebsiella pneumoniae was performed by Carl Friedländer[14] and Albert Fraenkel[15] in 1882 and 1884, respectively. Friedländer's initial work introduced Gram's stain, a fundamental laboratory test still used to categorize bacteria. Christian Gram's paper describing the procedure in 1884 helped differentiate the two different bacteria and establish that pneumonia could be caused by more than one microorganism.[16]

Sir William Osler appreciated the morbidity and mortality of pneumonia, describing it as the "captain of the men of death" in 1918. With the advent of penicillin and other antibiotics, modern surgical techniques, and intensive care in the twentieth century, mortality from pneumonia dropped precipitously in the developed world. Vaccination against Hemophilus influenzae type b began in 1988 and led to a dramatic decline in cases shortly thereafter.[17] Vaccination against Streptococcus pneumoniae in adults began in 1977 and in children began in 2000 and resulted in a similar decline.[18]


  1. ^  Metlay, JP, Kapoor, WN, Fine, MJ. Does this patient have community-acquired pneumonia? Diagnosing pneumonia by history and physical examination. JAMA 1997; 278:1440. PMID 9356004
  2. ^  Syrjala H, Broas M, Suramo I, Ojala A, Lahde S. High resolution computed tomography for the diagnosis of community-acquired pneumonia. Clin Infect Dis 1998; 27: 358-363 PMID 9709887
  3. ^ Fine MJ, Auble TE, Yealy DM, Hanusa BH, Weissfeld LA, Singer DE, Coley CM, Marrie TJ, Kapoor WN A prediction rule to identify low-risk patients with community-acquired pneumonia. N Engl J Med 1997. 243-50. 336:4 PMID 8995086
  4. ^  Combes A, Luyt CE, Fagon JY, Wollf M, Trouillet JL, Gibert C, Chastre J; PNEUMA Trial Group. Impact of methicillin resistance on outcome of Staphylococcus aureus ventilator-associated pneumonia. Am J Respir Crit Care Med. 2004 Oct 1;170(7):786-92. Epub 2004 Jul 8. PMID 15242840
  5. ^  Butler JC, Breiman RF, Campbell JF, Lipman HB, Broome CV, Facklam RR. Pneumococcal polysaccharide vaccine efficacy: an evaluation of current recommendations. JAMA 1993; 270: 1826-1831. PMID 8411526
  6. ^  Centers for Disease Control and Prevention. Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR 1999;48(RR-4):1-28.
  7. ^  Jefferson T, Deeks JJ, Demicheli V, Rivetti D, Rudin M. Amantadine and rimantadine for preventing and treating influenza A in adults. Cochrane Database Syst Rev. 2004;(3):CD001169. PMID 15266442
  8. ^  Hayden FG, Atmar RL, Schilling M, Johnson C, Poretz D, Paar D, Huson L, Ward P, Mills RG. Use of the selective oral neuraminidase inhibitor oseltamivir to prevent influenza. N Engl J Med 1999; 341: 1336-1343 PMID 10536125
  9. ^  Garenne, M, Ronsmans, C, Campbell, H. The magnitude of mortality from acute respiratory infections in children under 5 years in developing countries. World Health Stat Q 1992; 45:180. PMID 1462653
  10. ^ Almirall, J, Bolibar, I, Balanzo, X, Gonzalez, CA. Risk factors for community-acquired pneumonia in adults: A population-based case-control study. Eur Respir J 1999; 13:349. PMID 10065680
  11. ^  Hippocrates On Acute Diseases wikisource link
  12. ^  Maimonides Pirkei Moshe.
  13. ^  Klebs, E. Beiträge zur Kenntniss der pathogenen Schistomyceten. VII Die Monadinen. Arch. exptl. Pathol. Parmakol. 4 (5/6): 40-488, Dec. 10, 1875.
  14. ^  Friedländer, C. Über die Schizomyceten bei der acuten fibrösen Pneumonie. Virchow's Arch pathol. Anat. u. Physiol., 87 (2):319-324, Feb. 4, 1882.
  15. ^  Fraenkel, A. Über die genuine Pneumonie, Verhandlungen des Congres für innere Medicin. Dritter Congress, 3, 17-31, April 21, 1884.
  16. ^  Gram, C. Über die isolierte Färbung der Schizomyceten in Schnitt- und Trocken-präparaten. Fortschr. Med., 2 (6): 185-189, March 15, 1884.
  17. ^  Adams WG, Deaver KA, Cochi SL, et al. Decline of childhood Haemophilus influenzae type b (Hib) disease in the Hib vaccine era. JAMA 1993;269:221-6. PMID 8417239
  18. ^  Whitney CG, Farley MM, Hadler J, et al. Decline in invasive pneumococcal disease after the introduction of pneumococcal protein-polysaccharide conjugate vaccine. New Engl J Med 2003; 348; 1737-1746. PMID 12724479

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