Pneumonia

Not to be confused with Pneumonitis.
For other uses, see Pneumonia (disambiguation).

Pneumonia
Other namesPneumonitis
Chest X-ray of a pneumonia caused by influenza and Haemophilus influenzae, with patchy consolidations, mainly in the right upper lobe (arrow)
Pronunciation
SpecialtyPulmonology, infectious disease
SymptomsCough, shortness of breath, chest pain, fever[1]
DurationFew weeks[2]
CausesBacteria, virus, aspiration[3][4]
Risk factorsCystic fibrosis, COPD, sickle cell disease, asthma, diabetes, heart failure, history of smoking, very young age, older age[5][6][7]
Diagnostic methodBased on symptoms, chest X-ray[8]
Differential diagnosisCOPD, asthma, pulmonary edema, pulmonary embolism[9]
PreventionVaccines, handwashing, not smoking[10]
MedicationAntibiotics, antivirals, oxygen therapy[11][12]
Frequency450 million (7%) per year[12][13]
DeathsFour million per year[12][13]

Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli.[3][14] Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing.[15] The severity of the condition is variable.[15]

Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms.[a] Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and physical examination.[8] Chest X-rays, blood tests, and culture of the sputum may help confirm the diagnosis.[8] The disease may be classified by where it was acquired, such as community- or hospital-acquired or healthcare-associated pneumonia.[18]

Risk factors for pneumonia include cystic fibrosis, chronic obstructive pulmonary disease (COPD), sickle cell disease, asthma, diabetes, heart failure, a history of smoking, a poor ability to cough (such as following a stroke), and a weak immune system.[5][7]

Vaccines to prevent certain types of pneumonia (such as those caused by Streptococcus pneumoniae bacteria, linked to influenza, or linked to COVID-19) are available.[10] Other methods of prevention include hand washing to prevent infection, and not smoking.[10]

Treatment depends on the underlying cause.[19] Pneumonia believed to be due to bacteria is treated with antibiotics.[11] If the pneumonia is severe, the affected person is generally hospitalized.[19] Oxygen therapy may be used if oxygen levels are low.[11]

Each year, pneumonia affects about 450 million people globally (7% of the population) and results in about 4 million deaths.[12][13] With the introduction of antibiotics and vaccines in the 20th century, survival has greatly improved.[12] Nevertheless, pneumonia remains a leading cause of death in developing countries, and also among the very old, the very young, and the chronically ill.[12][20] Pneumonia often shortens the period of suffering among those already close to death and has thus been called "the old man's friend".[21]

Video summary (script)
  1. ^ "Pneumonia – Symptoms | NHLBI, NIH". nhlbi.nih.gov. 24 March 2022. Retrieved 1 October 2022.
  2. ^ Cite error: The named reference Behera2010 was invoked but never defined (see the help page).
  3. ^ a b c McLuckie A, ed. (2009). Respiratory disease and its management. New York: Springer. p. 51. ISBN 978-1-84882-094-4.
  4. ^ a b Pommerville JC (2010). Alcamo's Fundamentals of Microbiology (9th ed.). Sudbury, MA: Jones & Bartlett. p. 323. ISBN 978-0-7637-6258-2.
  5. ^ a b "Pneumonia – Causes and Risk Factors | NHLBI, NIH". nhlbi.nih.gov. 24 March 2022. Retrieved 1 October 2022.
  6. ^ Caldeira D, Alarcão J, Vaz-Carneiro A, Costa J (July 2012). "Risk of pneumonia associated with use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers: systematic review and meta-analysis". BMJ. 345 (jul11 1): e4260. doi:10.1136/bmj.e4260. PMC 3394697. PMID 22786934. Susceptibility is higher among elderly people (≥65 years)
  7. ^ a b "Complications and Treatments of Sickle Cell Disease | CDC". Centers for Disease Control and Prevention. 12 June 2019. Retrieved 6 May 2020.
  8. ^ a b c "How Is Pneumonia Diagnosed?". NHLBI. 1 March 2011. Archived from the original on 7 March 2016. Retrieved 3 March 2016.
  9. ^ Cite error: The named reference BMJ06 was invoked but never defined (see the help page).
  10. ^ a b c "How Can Pneumonia Be Prevented?". NHLBI. 1 March 2011. Archived from the original on 7 March 2016. Retrieved 3 March 2016.
  11. ^ a b c "How Is Pneumonia Treated?". NHLBI. 1 March 2011. Archived from the original on 6 March 2016. Retrieved 3 March 2016.
  12. ^ a b c d e f Ruuskanen O, Lahti E, Jennings LC, Murdoch DR (April 2011). "Viral pneumonia". Lancet. 377 (9773): 1264–75. doi:10.1016/S0140-6736(10)61459-6. PMC 7138033. PMID 21435708.
  13. ^ a b c Lodha R, Kabra SK, Pandey RM (June 2013). "Antibiotics for community-acquired pneumonia in children". The Cochrane Database of Systematic Reviews. 6 (6): CD004874. doi:10.1002/14651858.CD004874.pub4. PMC 7017636. PMID 23733365.
  14. ^ Leach RE (2009). Acute and Critical Care Medicine at a Glance (2nd ed.). Wiley-Blackwell. ISBN 978-1-4051-6139-8.
  15. ^ a b Ashby B, Turkington C (2007). The encyclopedia of infectious diseases (3rd ed.). New York: Facts on File. p. 242. ISBN 978-0-8160-6397-0. Retrieved 21 April 2011.
  16. ^ Lowe JF, Stevens A (2000). Pathology (2nd ed.). St. Louis: Mosby. p. 197. ISBN 978-0-7234-3200-5.
  17. ^ Bowden RA, Ljungman P, Snydman DR, eds. (2010). Transplant infections. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins. ISBN 978-1-58255-820-2.
  18. ^ "Types of Pneumonia". NHLBI. 1 March 2011. Archived from the original on 5 February 2016. Retrieved 2 March 2016.
  19. ^ a b "What Is Pneumonia?". NHLBI. 1 March 2011. Archived from the original on 29 February 2016. Retrieved 2 March 2016.
  20. ^ George RB (2005). Chest medicine: essentials of pulmonary and critical care medicine (5th ed.). Philadelphia: Lippincott Williams & Wilkins. p. 353. ISBN 978-0-7817-5273-2.
  21. ^ Eddy O (December 2005). "Community-Acquired Pneumonia: From Common Pathogens To Emerging Resistance". Emergency Medicine Practice. 7 (12).


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