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{{Short description|Inflammation of the alveoli of the lungs}}{{cs1 config|name-list-style=vanc}}{{confuse|Pneumonitis}}{{Other uses}}{{pp-semi-indef}}{{Good article}}{{Use dmy dates|date=March 2023}}

factoids

{{respell>newee-É™}}| synonyms = PneumonitisPulmonology, Infectious disease (medical specialty)>infectious diseaseshortness of breath, chest pain, feverPNEUMONIA – SYMPTOMS {{!, NHLBI, NIH website=nhlbi.nih.gov access-date=1 October 2022 |language=en}}| duration = Few weeks| onset = aspiration pneumonia>aspirationCystic fibrosis, COPD, sickle cell disease, asthma, diabetes mellitus>diabetes, heart failure, history of smoking, very young age, older agePNEUMONIA – CAUSES AND RISK FACTORS {{!, NHLBI, NIH >url=https://www.nhlbi.nih.gov/health/pneumonia/causes date=24 March 2022 language=en}}CALDEIRA D, ALARCãO J, VAZ-CARNEIRO A, COSTA J > TITLE = RISK OF PNEUMONIA ASSOCIATED WITH USE OF ANGIOTENSIN CONVERTING ENZYME INHIBITORS AND ANGIOTENSIN RECEPTOR BLOCKERS: SYSTEMATIC REVIEW AND META-ANALYSIS VOLUME = 345 PAGES = E4260 PMID = 22786934 DOI = 10.1136/BMJ.E4260, Susceptibility is higher among elderly people (≥65 years), | diagnosis = Based on symptoms, chest X-ray| differential = COPD, asthma, pulmonary edema, pulmonary embolism| prevention = Vaccines, handwashing, not smoking| medication = Antibiotics, antivirals, oxygen therapy| treatment = | frequency = 450 million (7%) per year| deaths = Four million per year}}Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli.BOOK, McLuckie A, Respiratory disease and its management, 2009, Springer, New York, 978-1-84882-094-4, 51, BOOK, Leach, Richard E., Acute and Critical Care Medicine at a Glance, 2nd, Wiley-Blackwell, 2009, 978-1-4051-6139-8,books.google.com/books?id=7u_wu5VCsVQC&pg=PT168, Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing.BOOK, Ashby, Bonnie, Turkington, Carol, The encyclopedia of infectious diseases, 3rd, Facts on File, New York, 2007, 242, 978-0-8160-6397-0,books.google.com/books?id=4Xlyaipv3dIC&pg=PA242, 21 April 2011, The severity of the condition is variable.Pneumonia is usually caused by infection with viruses or bacteria, and less commonly by other microorganisms.{{efn|The term pneumonia is sometimes more broadly applied to any condition resulting in inflammation of the lungs (caused for example by autoimmune diseases, chemical burns or certain medications),BOOK, Jeffrey C., Pommerville, Alcamo’s Fundamentals of Microbiology, 9th, Jones & Bartlett, Sudbury, MA, 2010, 323, 978-0-7637-6258-2,books.google.com/books?id=RJNQwQB8IxIC&pg=PA323, although this inflammation is more accurately referred to as pneumonitis.BOOK, Lowe JF, Stevens A, Pathology, 2nd, Mosby, St. Louis, 2000, 197, 978-0-7234-3200-5,books.google.com/books?id=AfVxLi4QTZQC&pg=PA197, BOOK, Bowden, Raleigh A., Ljungman, Per, Snydman, David R., Transplant infections, 2010, Wolters Kluwer Health/Lippincott Williams & Wilkins, Philadelphia, 978-1-58255-820-2, }} Identifying the responsible pathogen can be difficult. Diagnosis is often based on symptoms and physical examination. Chest X-rays, blood tests, and culture of the sputum may help confirm the diagnosis.WEB, How Is Pneumonia Diagnosed?,www.nhlbi.nih.gov/health/health-topics/topics/pnu/diagnosis, NHLBI, 3 March 2016, 1 March 2011, live,www.nhlbi.nih.gov/health/health-topics/topics/pnu/diagnosis," title="web.archive.org/web/20160307133513www.nhlbi.nih.gov/health/health-topics/topics/pnu/diagnosis,">web.archive.org/web/20160307133513www.nhlbi.nih.gov/health/health-topics/topics/pnu/diagnosis, 7 March 2016, The disease may be classified by where it was acquired, such as community- or hospital-acquired or healthcare-associated pneumonia.WEB, Types of Pneumonia,www.nhlbi.nih.gov/health/health-topics/topics/pnu/types, NHLBI, 2 March 2016, 1 March 2011,www.nhlbi.nih.gov/health/health-topics/topics/pnu/types," title="web.archive.org/web/20160205213840www.nhlbi.nih.gov/health/health-topics/topics/pnu/types,">web.archive.org/web/20160205213840www.nhlbi.nih.gov/health/health-topics/topics/pnu/types, 5 February 2016, 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.WEB, Complications and Treatments of Sickle Cell Disease {{!, CDC |url=https://www.cdc.gov/ncbddd/sicklecell/treatments.html |website=Centers for Disease Control and Prevention |access-date=6 May 2020 |language=en-us |date=12 June 2019}}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. Other methods of prevention include hand washing to prevent infection, and not smoking.WEB, How Can Pneumonia Be Prevented?,www.nhlbi.nih.gov/health/health-topics/topics/pnu/prevention, NHLBI, 3 March 2016, 1 March 2011, live,www.nhlbi.nih.gov/health/health-topics/topics/pnu/prevention," title="web.archive.org/web/20160307133901www.nhlbi.nih.gov/health/health-topics/topics/pnu/prevention,">web.archive.org/web/20160307133901www.nhlbi.nih.gov/health/health-topics/topics/pnu/prevention, 7 March 2016, Treatment depends on the underlying cause.WEB, What Is Pneumonia?,www.nhlbi.nih.gov/health/health-topics/topics/pnu, NHLBI, 2 March 2016, 1 March 2011, live,web.archive.org/web/20160229143108/https://www.nhlbi.nih.gov/health/health-topics/topics/pnu/, 29 February 2016, Pneumonia believed to be due to bacteria is treated with antibiotics.WEB, How Is Pneumonia Treated?,www.nhlbi.nih.gov/health/health-topics/topics/pnu/treatment, NHLBI, 3 March 2016, 1 March 2011, live,www.nhlbi.nih.gov/health/health-topics/topics/pnu/treatment," title="web.archive.org/web/20160306030735www.nhlbi.nih.gov/health/health-topics/topics/pnu/treatment,">web.archive.org/web/20160306030735www.nhlbi.nih.gov/health/health-topics/topics/pnu/treatment, 6 March 2016, If the pneumonia is severe, the affected person is generally hospitalized. Oxygen therapy may be used if oxygen levels are low.Each year, pneumonia affects about 450 million people globally (7% of the population) and results in about 4 million deaths.JOURNAL, Ruuskanen O, Lahti E, Jennings LC, Murdoch DR, Viral pneumonia, Lancet, 377, 9773, 1264–75, April 2011, 21435708, 7138033, 10.1016/S0140-6736(10)61459-6, JOURNAL, Lodha R, Kabra SK, Pandey RM, Antibiotics for community-acquired pneumonia in children, The Cochrane Database of Systematic Reviews, 6, 6, CD004874, June 2013, 23733365, 7017636, 10.1002/14651858.CD004874.pub4, With the introduction of antibiotics and vaccines in the 20th century, survival has greatly improved. Nevertheless, pneumonia remains a leading cause of death in developing countries, and also among the very old, the very young, and the chronically ill.BOOK, George, Ronald B., Chest medicine: essentials of pulmonary and critical care medicine, 2005, Lippincott Williams & Wilkins, Philadelphia, 978-0-7817-5273-2, 353,books.google.com/books?id=ZzlX2zJMbdgC&pg=PA353, 5th, Pneumonia often shortens the period of suffering among those already close to death and has thus been called “the old man’s friend”.JOURNAL, Eddy, Orin, Community-Acquired Pneumonia: From Common Pathogens To Emerging Resistance, Emergency Medicine Practice, Dec 2005, 7, 12,www.ebmedicine.net/topics.php?paction=showTopic&topic_id=118, File:En.Pseudopedia-VideoWiki-Pneumonia.webm|thumb|thumbtime=0:20|upright=1.4|Video summary ((Pseudopedia:VideoWiki/Pneumonia|script))]]{{TOC limit}}

Signs and symptoms{|class“wikitable” align“right” style@margin-left:0.4em;”

!colspan=2| Symptoms frequency! Symptom !! Frequency 79–91% 90% 71–75% 67–75% 60–65% 39–49%(File:Symptoms of pneumonia.svg|thumb|left|upright=1.3|alt=A diagram of the human body outlining the key symptoms of pneumonia|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, and an increased rate of breathing. In elderly people, confusion may be the most prominent sign.JOURNAL, Hoare Z, Lim WS, Pneumonia: update on diagnosis and management, BMJ, 332, 7549, 1077–79, May 2006, 16675815, 1458569, 10.1136/bmj.332.7549.1077, The typical signs and symptoms in children under five are fever, cough, and fast or difficult breathing. Fever is not very specific, as it occurs in many other common illnesses and may be absent in those with severe disease, malnutrition or in the elderly. In addition, a cough is frequently absent in children less than 2 months old. More severe signs and symptoms in children may include blue-tinged skin, unwillingness to drink, convulsions, ongoing vomiting, extremes of temperature, or a decreased level of consciousness.Bacterial and viral cases of pneumonia usually result in similar symptoms. Some causes are associated with classic, but non-specific, clinical characteristics. Pneumonia caused by Legionella may occur with abdominal pain, diarrhea, or confusion.JOURNAL, Darby J, Buising K, October 2008, Could it be Legionella?, Australian Family Physician, 37, 10, 812–15, 19002299, Pneumonia caused by Streptococcus pneumoniae is associated with rusty colored sputum.JOURNAL, Ortqvist A, Hedlund J, Kalin M, December 2005, Streptococcus pneumoniae: epidemiology, risk factors, and clinical features, Seminars in Respiratory and Critical Care Medicine, 26, 6, 563–74, 10.1055/s-2005-925523, 16388428, 260320485, Pneumonia caused by Klebsiella may have bloody sputum often described as “currant jelly”.BOOK, Tintinalli, Judith E., Emergency Medicine: A Comprehensive Study Guide (Emergency Medicine (Tintinalli)), McGraw-Hill Companies, New York, 2010, 480, 978-0-07-148480-0, Bloody sputum (known as hemoptysis) may also occur with tuberculosis, Gram-negative pneumonia, lung abscesses and more commonly acute bronchitis. Pneumonia caused by Mycoplasma pneumoniae may occur in association with swelling of the lymph nodes in the neck, joint pain, or a middle ear infection. Viral pneumonia presents more commonly with wheezing than bacterial pneumonia. Pneumonia was historically divided into “typical” and “atypical” based on the belief that the presentation predicted the underlying cause. However, evidence has not supported this distinction, therefore it is no longer emphasized.

Cause

File:Streptococcus pneumoniae.jpg|thumb|alt=Three lone round objects in a black background|The bacterium Streptococcus pneumoniae, a common cause of pneumonia, imaged by an electron microscopeelectron microscopePneumonia is due to infections caused primarily by bacteria or viruses and less commonly by fungi and parasites. Although more than 100 strains of infectious agents have been identified, only a few are responsible for the majority of cases. Mixed infections with both viruses and bacteria may occur in roughly 45% of infections in children and 15% of infections in adults. A causative agent may not be isolated in about half of cases despite careful testing. In an active population-based surveillance for community-acquired pneumonia requiring hospitalization in five hospitals in Chicago and Nashville from January 2010 through June 2012, 2259 patients were identified who had radiographic evidence of pneumonia and specimens that could be tested for the responsible pathogen.JOURNAL, Jain S, Self WH, Wunderink RG, Fakhran S, Balk R, Bramley AM, Reed C, Grijalva CG, Anderson EJ, Courtney DM, Chappell JD, Qi C, Hart EM, Carroll F, Trabue C, Donnelly HK, Williams DJ, Zhu Y, Arnold SR, Ampofo K, Waterer GW, Levine M, Lindstrom S, Winchell JM, Katz JM, Erdman D, Schneider E, Hicks LA, McCullers JA, Pavia AT, Edwards KM, Finelli L, Community-Acquired Pneumonia Requiring Hospitalization among U.S. Adults, The New England Journal of Medicine, 373, 5, 415–27, July 2015, 26172429, 4728150, 10.1056/NEJMoa1500245, Most patients (62%) had no detectable pathogens in their sample, and unexpectedly, respiratory viruses were detected more frequently than bacteria. Specifically, 23% had one or more viruses, 11% had one or more bacteria, 3% had both bacterial and viral pathogens, and 1% had a fungal or mycobacterial infection. “The most common pathogens were human rhinovirus (in 9% of patients), influenza virus (in 6%), and Streptococcus pneumoniae (in 5%).“The term pneumonia is sometimes more broadly applied to any condition resulting in inflammation of the lungs (caused for example by autoimmune diseases, chemical burns or drug reactions); however, this inflammation is more accurately referred to as pneumonitis.Factors that predispose to pneumonia include smoking, immunodeficiency, alcoholism, chronic obstructive pulmonary disease, sickle cell disease (SCD), asthma, chronic kidney disease, liver disease, and biological aging.BOOK, Marrie, Thomas J., Community-acquired pneumonia, 2002, Kluwer Academic Publishers, New York, 978-0-306-46834-6, 20,books.google.com/books?id=Yc0RBwAAQBAJ&pg=PA20, Additional risks in children include not being breastfed, exposure to cigarette smoke and other air pollution, malnutrition, and poverty.JOURNAL, Nguyen TK, Tran TH, Roberts CL, Fox GJ, Graham SM, Marais BJ, Risk factors for child pneumonia – focus on the Western Pacific Region, Paediatric Respiratory Reviews, 21, 95–101, January 2017, 27515732, 10.1016/j.prrv.2016.07.002, The use of acid-suppressing medications – such as proton-pump inhibitors or H2 blockers – is associated with an increased risk of pneumonia.JOURNAL, Eom CS, Jeon CY, Lim JW, Cho EG, Park SM, Lee KS, Use of acid-suppressive drugs and risk of pneumonia: a systematic review and meta-analysis, CMAJ, 183, 3, 310–19, February 2011, 21173070, 3042441, 10.1503/cmaj.092129, Approximately 10% of people who require mechanical ventilation develop ventilator-associated pneumonia,JOURNAL, Arthur LE, Kizor RS, Selim AG, van Driel ML, Seoane L, Antibiotics for ventilator-associated pneumonia, The Cochrane Database of Systematic Reviews, 2016, CD004267, October 2016, 10, 27763732, 6461148, 10.1002/14651858.CD004267.pub4, and people with a gastric feeding tube have an increased risk of developing aspiration pneumonia.JOURNAL, Alkhawaja S, Martin C, Butler RJ, Gwadry-Sridhar F, Post-pyloric versus gastric tube feeding for preventing pneumonia and improving nutritional outcomes in critically ill adults, The Cochrane Database of Systematic Reviews, 8, CD008875, August 2015, 2018, 26241698, 6516803, 10.1002/14651858.CD008875.pub2, Moreover, the misplacement of a feeding tube can lead to aspiration pneumonia. 28% of tube malposition results in pneumonia.WEB, 5 March 2013, Interprofessional Task force Uses a collaborative approach for internal feeding tube management,issuu.com/umms/docs/nv-winter_2013, 16 January 2023, News and Views, 10, en, JOURNAL, 17 November 2016, ASPEN Safe Practices for Enteral Nutrition Therapy,eclass.hua.gr/modules/document/file.php/DIET159/JPEN%20J%20Parenter%20Enteral%20Nutr-2016-Boullata-0148607116673053.pdf, Journal of Parenteral and Enteral Nutrition, XX, X, 16 January 2023, 16 January 2023,web.archive.org/web/20230116100215/https://eclass.hua.gr/modules/document/file.php/DIET159/JPEN%20J%20Parenter%20Enteral%20Nutr-2016-Boullata-0148607116673053.pdf, As with Avanos Medical’s feeding tube placement system, the CORTRAK* 2 EAS, which was recalled in May 2022 by the FDA due to adverse events reported, including pneumonia, caused a total of 60 injuries and 23 patient deaths, as communicated by the FDA.JOURNAL, 21 March 2022, Urgent: Field Correction Cortrak* 2 Enteral Access System (EAS),static.foxnews.com/foxnews.com/content/uploads/2022/04/Avanos_CORTRAK2_Field_Correction_Letter.pdf, Avanos, 1–2, WEB, Park, Andrea, 16 May 2022, Avanos Medical faces Class I recall for feeding tube system linked to 23 deaths since 2015,www.fiercebiotech.com/medtech/avanos-medical-faces-class-i-recall-feeding-tube-system-linked-23-deaths-2015, 16 January 2023, Fierce Biotech, en, JOURNAL, Health, Center for Devices and Radiological, 16 May 2022, Avanos Medical Recalls Cortrak*2 Enteral Access System for Risk of Misplaced Enteral Tubes Could Cause Patient Harm,www.fda.gov/medical-devices/medical-device-recalls/avanos-medical-recalls-cortrak2-enteral-access-system-risk-misplaced-enteral-tubes-could-cause, FDA, en, For people with certain variants of the FER gene, the risk of death is reduced in sepsis caused by pneumonia. However, for those with TLR6 variants, the risk of getting Legionnaires’ disease is increased.

Bacteria

(File:MRSAPneumoCT.png|thumb|Cavitating pneumonia due to MRSA as seen on a CT scan)Bacteria are the most common cause of community-acquired pneumonia (CAP), with Streptococcus pneumoniae isolated in nearly 50% of cases.JOURNAL, Anevlavis S, Bouros D, Community acquired bacterial pneumonia, Expert Opinion on Pharmacotherapy, 11, 3, 361–74, February 2010, 20085502, 10.1517/14656560903508770, 24376187, Other commonly isolated bacteria include Haemophilus influenzae in 20%, Chlamydophila pneumoniae in 13%, and Mycoplasma pneumoniae in 3% of cases; Staphylococcus aureus; Moraxella catarrhalis; and Legionella pneumophila. A number of drug-resistant versions of the above infections are becoming more common, including drug-resistant Streptococcus pneumoniae (DRSP) and methicillin-resistant Staphylococcus aureus (MRSA).The spreading of organisms is facilitated by certain risk factors. Alcoholism is associated with Streptococcus pneumoniae, anaerobic organisms, and Mycobacterium tuberculosis; smoking facilitates the effects of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Legionella pneumophila. Exposure to birds is associated with Chlamydia psittaci; farm animals with Coxiella burnetti; aspiration of stomach contents with anaerobic organisms; and cystic fibrosis with Pseudomonas aeruginosa and Staphylococcus aureus. Streptococcus pneumoniae is more common in the winter, and it should be suspected in persons aspirating a large number of anaerobic organisms.

Viruses

File:SARS xray.jpg|thumb|A chest x-ray of a patient with severe viral pneumonia due to SARS ]]In adults, viruses account for about one third of pneumonia cases, and in children for about 15% of them. Commonly implicated agents include rhinoviruses, coronaviruses, influenza virus, respiratory syncytial virus (RSV), adenovirus, and parainfluenza. Herpes simplex virus rarely causes pneumonia, except in groups such as newborns, persons with cancer, transplant recipients, and people with significant burns.BOOK, Behera D, Textbook of pulmonary medicine, 2010, Jaypee Brothers Medical Pub., New Delhi, 978-81-8448-749-7, 391–94,books.google.com/books?id=0TbJjd9eTp0C&pg=PA391, 2nd, {{Dead link|date=September 2023 |bot=InternetArchiveBot |fix-attempted=yes }} After organ transplantation or in otherwise immunocompromised persons, there are high rates of cytomegalovirus pneumonia. Those with viral infections may be secondarily infected with the bacteria Streptococcus pneumoniae, Staphylococcus aureus, or Haemophilus influenzae, particularly when other health problems are present. Different viruses predominate at different times of the year; during flu season, for example, influenza may account for more than half of all viral cases. Outbreaks of other viruses also occur occasionally, including hantaviruses and coronaviruses. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can also result in pneumonia.JOURNAL, Lai CC, Shih TP, Ko WC, Tang HJ, Hsueh PR, Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and coronavirus disease-2019 (COVID-19): The epidemic and the challenges, International Journal of Antimicrobial Agents, 55, 3, 105924, March 2020, 32081636, 7127800, 10.1016/j.ijantimicag.2020.105924, free,

Fungi

Fungal pneumonia is uncommon, but occurs more commonly in individuals with weakened immune systems due to AIDS, immunosuppressive drugs, or other medical problems.BOOK, Maskell, Nick, Millar, Ann, Oxford Desk Reference: Respiratory Medicine, 2009, Oxford University Press, Oxford, 978-0-19-923912-2, 196,books.google.com/books?id=MfEUkzQQ1BEC&pg=PA196, It is most often caused by Histoplasma capsulatum, Blastomyces, Cryptococcus neoformans, Pneumocystis jiroveci (pneumocystis pneumonia, or PCP), and Coccidioides immitis. Histoplasmosis is most common in the Mississippi River basin, and coccidioidomycosis is most common in the Southwestern United States. The number of cases of fungal pneumonia has been increasing in the latter half of the 20th century due to increasing travel and rates of immunosuppression in the population. For people infected with HIV/AIDS, PCP is a common opportunistic infection.JOURNAL, Ewald H, Raatz H, Boscacci R, Furrer H, Bucher HC, Briel M, Adjunctive corticosteroids for Pneumocystis jiroveci pneumonia in patients with HIV infection, The Cochrane Database of Systematic Reviews, 4, CD006150, April 2015, 2015, 25835432, 6472444, 10.1002/14651858.CD006150.pub2,

Parasites

A variety of parasites can affect the lungs, including Toxoplasma gondii, Strongyloides stercoralis, Ascaris lumbricoides, and Plasmodium malariae.Murray and Nadel (2010). Chapter 37. These organisms typically enter the body through direct contact with the skin, ingestion, or via an insect vector. Except for Paragonimus westermani, most parasites do not specifically affect the lungs but involve the lungs secondarily to other sites. Some parasites, in particular those belonging to the Ascaris and Strongyloides genera, stimulate a strong eosinophilic reaction, which may result in eosinophilic pneumonia. In other infections, such as malaria, lung involvement is due primarily to cytokine-induced systemic inflammation. In the developed world, these infections are most common in people returning from travel or in immigrants. Around the world, parasitic pneumonia is most common in the immunodeficient.JOURNAL, Vijayan VK, Parasitic lung infections, Current Opinion in Pulmonary Medicine, 15, 3, 274–82, May 2009, 19276810, 10.1097/MCP.0b013e328326f3f8, 2631717,

Noninfectious

Idiopathic interstitial pneumonia or noninfectious pneumoniaBOOK, Root, Richard K., Clinical infectious diseases: a practical approach, 1999, Oxford Univ. Press, New York [u.a.], 978-0-19-508103-9, 833,books.google.com/books?id=zvCOpighJggC&pg=PA833, is 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.BOOK, Costabel U, Diffuse parenchymal lung disease: 47 tables, 2007, Karger, Basel, 978-3-8055-8153-0, 4, [Online-Ausg.], Lipoid pneumonia is another rare cause due to lipids entering the lung. These lipids can either be inhaled or spread to the lungs from elsewhere in the body.JOURNAL, Hadda V, Khilnani GC, December 2010, Lipoid pneumonia: an overview,www.worldcat.org/title/262559133, Expert Review of Respiratory Medicine, 4, 6, 799–807, 10.1586/ers.10.74, 262559133, 21128754, 44309610,

Mechanisms

File:New Pneumonia cartoon.jpg|thumb|upright=1.3|alt=A schematic diagram of the human lungs with an empty circle on the left representing a normal alveolus and one on the right showing an alveolus full of fluid as in pneumonia|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 an upper respiratory tract infection that moves into the lower respiratory tract.JOURNAL, Ranganathan SC, Sonnappa S, Pneumonia and other respiratory infections, Pediatric Clinics of North America, 56, 1, 135–56, xi, February 2009, 19135585, 7111724, 10.1016/j.pcl.2008.10.005, It is a type of pneumonitis (lung inflammation).BOOK, Anderson, Douglas M., Dorland’s illustrated medical dictionary, 2000, Saunders, Philadelphia [u.a.], 978-0-7216-8261-7, 1414, 29,archive.org/details/trent_0116404640520/page/1414, The normal flora of the upper airway give protection by competing with pathogens for nutrients. In the lower airways, reflexes of the glottis, actions of complement proteins and immunoglobulins are important for protection. Microaspiration of contaminated secretions can infect the lower airways and cause pneumonia. The progress of pneumonia is determined by the virulence of the organism; the amount of organism required to start an infection; and the body’s immune response against the infection.

Bacterial

Most bacteria enter the lungs via small aspirations of organisms residing in the throat or nose. Half of normal people have these small aspirations during sleep. While the throat always contains bacteria, potentially infectious ones reside there only at certain times and under certain conditions. A minority of types of bacteria such as Mycobacterium tuberculosis and Legionella pneumophila reach the lungs via contaminated airborne droplets. Bacteria can also spread via the blood. Once in the lungs, bacteria may invade the spaces between cells and between alveoli, where the macrophages and neutrophils (defensive white blood cells) attempt to inactivate the bacteria.BOOK, Hammer, Gary D., McPhee, Stephen J., Pathophysiology of disease: an introduction to clinical medicine, 2010, McGraw-Hill Medical, New York, 978-0-07-162167-0, Chapter 4, 6th, The neutrophils also release cytokines, causing a general activation of the immune system.BOOK, Fein, Alan, Diagnosis and management of pneumonia and other respiratory infections, 2006, Professional Communications, Caddo, OK, 978-1-884735-63-9, 28–29,books.google.com/books?id=hKdcHK719qgC&pg=PA28, 2nd, This leads to the fever, chills, and fatigue common in bacterial pneumonia. The neutrophils, bacteria, and fluid from surrounding blood vessels fill the alveoli, resulting in the consolidation seen on chest X-ray.BOOK, Kumar, Vinay, Robbins and Cotran pathologic basis of disease., 2010, Saunders/Elsevier, Philadelphia, 978-1-4160-3121-5, Chapter 15, 8th,

Viral

Viruses may reach the lung by a number of different routes. Respiratory syncytial virus is typically contracted when people touch contaminated objects and then touch their eyes or nose.Murray and Nadel (2010). Chapter 31. Other viral infections occur when contaminated airborne droplets are inhaled through the nose or mouth. Once in the upper airway, the viruses may make their way into the lungs, where they invade the cells lining the airways, alveoli, or lung parenchyma. Some viruses such as measles and herpes simplex may reach the lungs via the blood.BOOK, Fleisher, Gary R., Ludwig, Stephen, Textbook of pediatric emergency medicine, 2010, Wolters Kluwer/Lippincott Williams & Wilkins Health, Philadelphia, 978-1-60547-159-4, 914,books.google.com/books?id=a7CqcE1ZrFkC&pg=PA914, 6th, The invasion of the lungs may lead to varying degrees of cell death. When the immune system responds to the infection, even more lung damage may occur. Primarily white blood cells, mainly mononuclear cells, generate the inflammation. As well as damaging the lungs, many viruses simultaneously affect other organs and thus disrupt other body functions. Viruses also make the body more susceptible to bacterial infections; in this way, bacterial pneumonia can occur at the same time as viral pneumonia.JOURNAL, Figueiredo LT, Viral pneumonia: epidemiological, clinical, pathophysiological and therapeutic aspects, Jornal Brasileiro de Pneumologia, 35, 9, 899–906, September 2009, 19820817, 10.1590/S1806-37132009000900012, free,

Diagnosis

{{listen| filename =Crackles pneumoniaO.ogg| title = Crackles| description = Crackles heard in the lungs of a person with pneumonia using a stethoscope.| format = Ogg}}Pneumonia is typically diagnosed based on a combination of physical signs and often a chest X-ray.JOURNAL, Lynch T, Bialy L, Kellner JD, Osmond MH, Klassen TP, Durec T, Leicht R, Johnson DW, A systematic review on the diagnosis of pediatric bacterial pneumonia: when gold is bronze, PLOS ONE, 5, 8, e11989, August 2010, 20700510, 2917358, 10.1371/journal.pone.0011989, Huicho, 2010PLoSO...511989L, Luis, free, In adults with normal vital signs and a normal lung examination, the diagnosis is unlikely.JOURNAL, Marchello CS, Ebell MH, Dale AP, Harvill ET, Shen Y, Whalen CC, Signs and Symptoms That Rule out Community-Acquired Pneumonia in Outpatient Adults: A Systematic Review and Meta-Analysis, Journal of the American Board of Family Medicine, 32, 2, 234–47, 2019, 30850460, 7422644, 10.3122/jabfm.2019.02.180219, free, However, the underlying cause can be difficult to confirm, as there is no definitive test able to distinguish between bacterial and non-bacterial cause. The overall impression of a physician appears to be at least as good as decision rules for making or excluding the diagnosis.JOURNAL, Dale AP, Marchello C, Ebell MH, Clinical gestalt to diagnose pneumonia, sinusitis, and pharyngitis: a meta-analysis, The British Journal of General Practice, 69, 684, e444–e453, July 2019, 31208974, 6582453, 10.3399/bjgp19X704297,

Diagnosis in children

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. A rapid respiratory rate is defined as greater than 60 breaths per minute in children under 2 months old, greater than 50 breaths per minute in children 2 months to 1 year old, or greater than 40 breaths per minute in children 1 to 5 years old.BOOK, Ezzati, Majid, Lopez, Alan D., Rodgers, Anthony, Murray, Christopher J.L., Comparative quantification of health risks, 2004, World Health Organization, Genève, 978-92-4-158031-1, 70,books.google.com/books?id=ACV1jEGx4AgC&pg=PA70, In children, low oxygen levels and lower chest indrawing are more sensitive than hearing chest crackles with a stethoscope or increased respiratory rate.JOURNAL, Shah SN, Bachur RG, Simel DL, Neuman MI, Does This Child Have Pneumonia?: The Rational Clinical Examination Systematic Review, JAMA, 318, 5, 462–71, August 2017, 28763554, 10.1001/jama.2017.9039, 44974175, Grunting and nasal flaring may be other useful signs in children less than five years old.JOURNAL, Rambaud-Althaus C, Althaus F, Genton B, D’Acremont V, Clinical features for diagnosis of pneumonia in children younger than 5 years: a systematic review and meta-analysis, The Lancet. Infectious Diseases, 15, 4, 439–50, April 2015, 25769269, 10.1016/s1473-3099(15)70017-4, Lack of wheezing is an indicator of Mycoplasma pneumoniae in children with pneumonia, but as an indicator it is not accurate enough to decide whether or not macrolide treatment should be used.JOURNAL, Wang K, Gill P, Perera R, Thomson A, Mant D, Harnden A, Clinical symptoms and signs for the diagnosis of Mycoplasma pneumoniae in children and adolescents with community-acquired pneumonia, The Cochrane Database of Systematic Reviews, 10, CD009175, October 2012, 10, 23076954, 7117561, 10.1002/14651858.CD009175.pub2, The presence of chest pain in children with pneumonia doubles the probability of Mycoplasma pneumoniae.

Diagnosis in adults

In general, in adults, investigations are not needed in mild cases. There is a very low risk of pneumonia if all vital signs and auscultation are normal.JOURNAL, Saldías F, Méndez JI, Ramírez D, Díaz O, [Predictive value of history and physical examination for the diagnosis of community-acquired pneumonia in adults: a literature review], Revista Médica de Chile, 135, 4, 517–28, April 2007, 17554463, 10.4067/s0034-98872007000400016, free, C-reactive protein (CRP) may help support the diagnosis.JOURNAL, Ebell MH, Bentivegna M, Cai X, Hulme C, Kearney M, Accuracy of Biomarkers for the Diagnosis of Adult Community-acquired Pneumonia: A Meta-analysis, Academic Emergency Medicine, 27, 3, 195–206, March 2020, 32100377, 10.1111/acem.13889, 211523779, free, For those with CRP less than 20 mg/L without convincing evidence of pneumonia, antibiotics are not recommended.Procalcitonin may help determine the cause and support decisions about who should receive antibiotics.JOURNAL, Schuetz P, Wirz Y, Sager R, Christ-Crain M, Stolz D, Tamm M, Bouadma L, Luyt CE, Wolff M, Chastre J, Tubach F, Kristoffersen KB, Burkhardt O, Welte T, Schroeder S, Nobre V, Wei L, Bucher HC, Annane D, Reinhart K, Falsey AR, Branche A, Damas P, Nijsten M, de Lange DW, Deliberato RO, Oliveira CF, Maravić-Stojković V, Verduri A, Beghé B, Cao B, Shehabi Y, Jensen JS, Corti C, van Oers JA, Beishuizen A, Girbes AR, de Jong E, Briel M, Mueller B, Effect of procalcitonin-guided antibiotic treatment on mortality in acute respiratory infections: a patient level meta-analysis, The Lancet. Infectious Diseases, 18, 1, 95–107, January 2018, 29037960, 10.1016/S1473-3099(17)30592-3, free, 1843/42632, free, Antibiotics are encouraged if the procalcitonin level reaches 0.25 μg/L, strongly encouraged if it reaches 0.5 μg/L, and strongly discouraged if the level is below 0.10 μg/L. In people requiring hospitalization, pulse oximetry, chest radiography and blood tests – including a complete blood count, serum electrolytes, C-reactive protein level, and possibly liver function tests – are recommended.The diagnosis of influenza-like illness can be made based on the signs and symptoms; however, confirmation of an influenza infection requires testing.JOURNAL, Call SA, Vollenweider MA, Hornung CA, Simel DL, McKinney WP, Does this patient have influenza?, JAMA, 293, 8, 987–97, February 2005, 15728170, 10.1001/jama.293.8.987, Thus, treatment is frequently based on the presence of influenza in the community or a rapid influenza test.Adults 65 years old or older, as well as cigarette smokers and people with ongoing medical conditions are at increased risk for pneumonia.WEB, 30 September 2022, Risk Factors for Pneumonia,www.cdc.gov/pneumonia/riskfactors.html, 16 January 2023, CDC, en-us,

Physical exam

Physical examination may sometimes reveal low blood pressure, high heart rate, or low oxygen saturation. The respiratory rate may be faster than normal, and this may occur a day or two before other signs. Examination of the chest may be normal, but it may show decreased 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. Crackles (rales) 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.

Imaging

(File:X-ray of lobar pneumonia.jpg|thumb|A chest X-ray showing a very prominent wedge-shaped area of airspace consolidation in the right lung characteristic of acute bacterial lobar pneumonia)(File:CT scan of the chest, demonstrating right-sided pneumonia.jpg|thumb|alt=A black-and-white image shows the internal organs in cross-section as generated by CT. Where one would expect black on the left, one sees a whiter area with black sticks through it.|CT of the chest demonstrating right-sided pneumonia (left side of the image))A chest radiograph is frequently used in diagnosis. In people with mild disease, imaging is needed only in those with potential complications, those not having improved with treatment, or those in which the cause is uncertain.JOURNAL, 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, BTS guidelines for the management of community acquired pneumonia in adults: update 2009, Thorax, 64, Suppl 3, iii, 1–55, October 2009, 19783532, 10.1136/thx.2009.121434, free, If a person is sufficiently sick to require hospitalization, a chest radiograph is recommended. Findings do not always match the severity of disease and do not reliably separate between bacterial and viral infection.X-ray presentations of pneumonia may be classified as lobar pneumonia, bronchopneumonia, lobular pneumonia, and interstitial pneumonia.BOOK, Helms, Clyde A., Brant, William E., Fundamentals of diagnostic radiology, Wolters Kluwer/Lippincott Williams & Wilkins, Philadelphia, 978-1-60831-911-4, 435,books.google.com/books?id=o_4eoeOinNgC&pg=PA435, 4th, 20 March 2012, Bacterial, community-acquired pneumonia classically show lung consolidation of one lung segmental lobe, which is known as lobar pneumonia. However, findings may vary, and other patterns are common in other types of pneumonia. Aspiration pneumonia may present with bilateral opacities primarily in the bases of the lungs and on the right side. Radiographs of viral pneumonia may appear normal, appear hyper-inflated, have bilateral patchy areas, or present similar to bacterial pneumonia with lobar consolidation. Radiologic findings may not be present in the early stages of the disease, especially in the presence of dehydration, or may be difficult to interpret in the obese or those with a history of lung disease. Complications such as pleural effusion may also be found on chest radiographs. Laterolateral chest radiographs can increase the diagnostic accuracy of lung consolidation and pleural effusion.A CT scan can give additional information in indeterminate cases and provide more details in those with an unclear chest radiograph (for example occult pneumonia in chronic obstructive pulmonary disease). They can be used to exclude pulmonary embolism and fungal pneumonia, and detect lung abscesses in those who are not responding to treatments. However, CT scans are more expensive, have a higher dose of radiation, and cannot be done at bedside.Lung ultrasound may also be useful in helping to make the diagnosis.JOURNAL, Llamas-Álvarez AM, Tenza-Lozano EM, Latour-Pérez J, February 2017, Accuracy of Lung Ultrasonography in the Diagnosis of Pneumonia in Adults: Systematic Review and Meta-Analysis,journal.chestnet.org/article/S0012-3692(16)62327-9/fulltext, Chest, 151, 2, 374–82, 10.1016/j.chest.2016.10.039, 27818332, 24399240, Ultrasound is radiation free and can be done at bedside. However, ultrasound requires specific skills to operate the machine and interpret the findings. It may be more accurate than chest X-ray.JOURNAL, Ye X, Xiao H, Chen B, Zhang S, Accuracy of Lung Ultrasonography versus Chest Radiography for the Diagnosis of Adult Community-Acquired Pneumonia: Review of the Literature and Meta-Analysis, PLOS ONE, 10, 6, e0130066, 2015, 26107512, 4479467, 10.1371/journal.pone.0130066, 2015PLoSO..1030066Y, free, File:UOTW 34 - Ultrasound of the Week 1.webm|Pneumonia seen by ultrasoundWEB, UOTW No. 34 – Ultrasound of the Week,www.ultrasoundoftheweek.com/uotw-34/, Ultrasound of the Week, 27 May 2017, 20 January 2015, live,web.archive.org/web/20170509114431/https://www.ultrasoundoftheweek.com/uotw-34/, 9 May 2017, File:UOTW 34 - Ultrasound of the Week 2.webm|Pneumonia seen by ultrasoundFile:UOTW 34 - Ultrasound of the Week 3.jpg|Pneumonia seen by ultrasoundFile:RtPneuKidMark.png|Right middle lobe pneumonia in a child as seen on plain X-ray

Microbiology

In people managed in the community, determining the causative agent is not cost-effective and typically does not alter management. For people who do not respond to treatment, sputum culture should be considered, and culture for Mycobacterium tuberculosis should be carried out in persons with a chronic productive cough. Microbiological evaluation is also indicated in severe pneumonia, alcoholism, asplenia, immunosuppression, HIV infection, and those being empirically treated for MRSA of pseudomonas.JOURNAL, Metlay JP, Waterer GW, Long AC, Anzueto A, Brozek J, Crothers K, Cooley LA, Dean NC, Fine MJ, Flanders SA, Griffin MR, Metersky ML, Musher DM, Restrepo MI, Whitney CG, Diagnosis and Treatment of Adults with Community-acquired Pneumonia. An Official Clinical Practice Guideline of the American Thoracic Society and Infectious Diseases Society of America, American Journal of Respiratory and Critical Care Medicine, 200, 7, e45–e67, October 2019, 31573350, 6812437, 10.1164/rccm.201908-1581ST, Although positive blood culture and pleural fluid culture definitively establish the diagnosis of the type of micro-organism involved, a positive sputum culture has to be interpreted with care for the possibility of colonisation of respiratory tract. Testing for other specific organisms may be recommended during outbreaks, for public health reasons. In those hospitalized for severe disease, both sputum and blood cultures are recommended, as well as testing the urine for antigens to Legionella and Streptococcus. Viral infections, can be confirmed via detection of either the virus or its antigens with culture or polymerase chain reaction (PCR), among other techniques. Mycoplasma, Legionella, Streptococcus, and Chlamydia can also be detected using PCR techniques on bronchoalveolar lavage and nasopharyngeal swab. The causative agent is determined in only 15% of cases with routine microbiological tests.

Classification

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.BOOK, Stedman’s medical dictionary.,archive.org/details/stedmansmedicald00sted_3, registration, 2006, Lippincott Williams & Wilkins, Philadelphia, 978-0-7817-6450-6, 28th, Pneumonia is most commonly classified by where or how it was acquired: community-acquired, aspiration, healthcare-associated, hospital-acquired, and ventilator-associated pneumonia.JOURNAL, Sharma S, Maycher B, Eschun G, Radiological imaging in pneumonia: recent innovations, Current Opinion in Pulmonary Medicine, 13, 3, 159–69, May 2007, 17414122, 10.1097/MCP.0b013e3280f3bff4, 39554602, It may also be classified by the area of the lung affected: lobar, bronchial pneumonia and acute interstitial pneumonia; or by the causative organism.JOURNAL, Dunn L, 29 June – 5 July 2005, Pneumonia: classification, diagnosis and nursing management,journals.rcni.com/doi/abs/10.7748/ns2005.06.19.42.50.c3901, Nursing Standard, 19, 42, 50–54, 10.7748/ns2005.06.19.42.50.c3901, 16013205, Pneumonia in children may additionally be classified based on signs and symptoms as non-severe, severe, or very severe.BOOK,books.google.com/books?id=xbkbRG5XYxsC&pg=PA72, Pocket Book of Hospital Care for Children: Guidelines for the Management of Common Illnesses with Limited Resources, World Health Organization, 2005, 978-92-4-154670-6, Geneva, 72, The setting in which pneumonia develops is important to treatment,JOURNAL, Anand N, Kollef MH, February 2009, The alphabet soup of pneumonia: CAP, HAP, HCAP, NHAP, and VAP, Seminars in Respiratory and Critical Care Medicine, 30, 1, 3–9, 10.1055/s-0028-1119803, 19199181, 260320494, as it correlates to which pathogens are likely suspects, which mechanisms are likely, which antibiotics are likely to work or fail, and which complications can be expected based on the person’s health status.

Community

Community-acquired pneumonia (CAP) is acquired in the community, outside of health care facilities. Compared with healthcare-associated pneumonia, it is less likely to involve multidrug-resistant bacteria. Although the latter are no longer rare in CAP, they are still less likely. Prior stays in healthcare-related environments such as hospitals, nursing homes, or hemodialysis centers or a history of receiving domiciliary care can increase patients’ risk for CAP caused by multidrug-resistant bacteria.JOURNAL, Falcone, Marco, Russo, Alessandro, Giannella, Maddalena, Cangemi, Roberto, Scarpellini, Maria Gabriella, Bertazzoni, Giuliano, Alarcón, José Martínez, Taliani, Gloria, Palange, Paolo, Farcomeni, Alessio, Vestri, Annarita, Bouza, Emilio, Violi, Francesco, Venditti, Mario, 10 April 2015, Salluh, Jorge IF, Individualizing Risk of Multidrug-Resistant Pathogens in Community-Onset Pneumonia, PLOS ONE, en, 10, 4, e0119528, 10.1371/journal.pone.0119528, 1932-6203, 4393134, 25860142, 2015PLoSO..1019528F, free,

Healthcare

Health care–associated pneumonia (HCAP) is an infection associated with recent exposure to the health care system, including hospitals, outpatient clinics, nursing homes, dialysis centers, chemotherapy treatment, or home care. HCAP is sometimes called MCAP (medical care–associated pneumonia).People may become infected with pneumonia in a hospital; this is defined as pneumonia not present at the time of admission (symptoms must start at least 48 hours after admission).JOURNAL, 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,www.atsjournals.org/doi/10.1164/rccm.200405-644ST, American Journal of Respiratory and Critical Care Medicine, 171, 4, 388–416, 10.1164/rccm.200405-644ST, 15699079, It is likely to involve hospital-acquired infections, with higher risk of multidrug-resistant pathogens. People in a hospital often have other medical conditions, which may make them more susceptible to pathogens in the hospital.Ventilator-associated pneumonia occurs in people breathing with the help of mechanical ventilation. Ventilator-associated pneumonia is specifically defined as pneumonia that arises more than 48 to 72 hours after endotracheal intubation.

Differential diagnosis

Several diseases can present with similar signs and symptoms to pneumonia, such as: chronic obstructive pulmonary disease, asthma, pulmonary edema, bronchiectasis, lung cancer, and pulmonary emboli. 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 present with acute onset sharp chest pain and shortness of breath. Mild pneumonia should be differentiated from upper respiratory tract infection (URTI). Severe pneumonia should be differentiated from acute heart failure. Pulmonary infiltrates that resolved after giving mechanical ventilation should point to heart failure and atelectasis rather than pneumonia. For recurrent pneumonia, underlying lung cancer, metastasis, tuberculosis, a foreign bodies, immunosuppression, and hypersensitivity should be suspected.JOURNAL, Prina E, Ranzani OT, Torres A, Community-acquired pneumonia, Lancet, 386, 9998, 1097–108, September 2015, 26277247, 7173092, 10.1016/S0140-6736(15)60733-4,

Prevention

Prevention includes vaccination, environmental measures, and appropriate treatment of other health problems. It is believed that, if appropriate preventive measures were instituted globally, mortality among children could be reduced by 400,000; and, if proper treatment were universally available, childhood deaths could be decreased by another 600,000.

Vaccination

Vaccination prevents against certain bacterial and viral pneumonias both in children and adults. Influenza vaccines are modestly effective at preventing symptoms of influenza,JOURNAL, Demicheli V, Jefferson T, Ferroni E, Rivetti A, Di Pietrantonj C, Vaccines for preventing influenza in healthy adults, The Cochrane Database of Systematic Reviews, 2020, CD001269, February 2018, 2, 29388196, 6491184, 10.1002/14651858.CD001269.pub6, The Centers for Disease Control and Prevention (CDC) recommends yearly influenza vaccination for every person 6 months and older.WEB, Seasonal Influenza (Flu),www.cdc.gov/flu/, Centers for Disease Control and Prevention, 29 June 2011, live,www.cdc.gov/flu/," title="web.archive.org/web/20110629190823www.cdc.gov/flu/,">web.archive.org/web/20110629190823www.cdc.gov/flu/, 29 June 2011, Immunizing health care workers decreases the risk of viral pneumonia among their patients.JOURNAL, Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG, Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults, Clinical Infectious Diseases, 44, Suppl 2, S27–72, March 2007, 17278083, 7107997, 10.1086/511159, free, Vaccinations against Haemophilus influenzae and Streptococcus pneumoniae have good evidence to support their use. There is strong evidence for vaccinating children under the age of 2 against Streptococcus pneumoniae (pneumococcal conjugate vaccine).JOURNAL, Lucero MG, Dulalia VE, Nillos LT, Williams G, Parreño RA, Nohynek H, Riley ID, Makela H, Pneumococcal conjugate vaccines for preventing vaccine-type invasive pneumococcal disease and X-ray defined pneumonia in children less than two years of age, The Cochrane Database of Systematic Reviews, 4, CD004977, October 2009, 2009, 19821336, 6464899, 10.1002/14651858.CD004977.pub2, WEB,www.who.int/biologicals/areas/vaccines/pneumo/en/,www.who.int/biologicals/areas/vaccines/pneumo/en/," title="web.archive.org/web/20080428235941www.who.int/biologicals/areas/vaccines/pneumo/en/,">web.archive.org/web/20080428235941www.who.int/biologicals/areas/vaccines/pneumo/en/, 28 April 2008, WHO {{!, Pneumococcal conjugate vaccines|website=who.int|access-date=16 January 2018}}WEB,www.cdc.gov/pneumococcal/vaccination.html, Pneumococcal Disease {{!, Vaccines – PCV13 and PPSV23 {{!}} CDC|date=18 September 2017|website=cdc.gov|language=en-us|access-date=16 January 2018}} Vaccinating children against Streptococcus pneumoniae has led to a decreased rate of these infections in adults, because many adults acquire infections from children. A Streptococcus pneumoniae vaccine is available for adults, and has been found to decrease the risk of invasive pneumococcal disease by 74%, but there is insufficient evidence to suggest using the pneumococcal vaccine to prevent pneumonia or death in the general adult population.JOURNAL, Moberley S, Holden J, Tatham DP, Andrews RM, Vaccines for preventing pneumococcal infection in adults, The Cochrane Database of Systematic Reviews, 1, 1, CD000422, January 2013, 23440780, 7045867, 10.1002/14651858.CD000422.pub3, The CDC recommends that young children and adults over the age of 65 receive the pneumococcal vaccine, as well as older children or younger adults who have an increased risk of getting pneumococcal disease. The pneumococcal vaccine has been shown to reduce the risk of community acquired pneumonia in people with chronic obstructive pulmonary disease, but does not reduce mortality or the risk of hospitalization for people with this condition.JOURNAL, Walters JA, Tang JN, Poole P, Wood-Baker R, Pneumococcal vaccines for preventing pneumonia in chronic obstructive pulmonary disease, The Cochrane Database of Systematic Reviews, 1, CD001390, January 2017, 3, 28116747, 6422320, 10.1002/14651858.CD001390.pub4, People with COPD are recommended by a number of guidelines to have a pneumococcal vaccination. Other vaccines for which there is support for a protective effect against pneumonia include pertussis, varicella, and measles.

Medications

When influenza outbreaks occur, medications such as amantadine or rimantadine may help prevent the condition, but they are associated with side effects.JOURNAL, Jefferson T, Demicheli V, Di Pietrantonj C, Rivetti D, Amantadine and rimantadine for influenza A in adults, The Cochrane Database of Systematic Reviews, 2, CD001169, April 2006, 2006, 16625539, 7068158, 10.1002/14651858.CD001169.pub3, Zanamivir or oseltamivir decrease the chance that people who are exposed to the virus will develop symptoms; however, it is recommended that potential side effects are taken into account.JOURNAL, Jefferson T, Jones MA, Doshi P, Del Mar CB, Hama R, Thompson MJ, Spencer EA, Onakpoya I, Mahtani KR, Nunan D, Howick J, Heneghan CJ, Neuraminidase inhibitors for preventing and treating influenza in healthy adults and children, The Cochrane Database of Systematic Reviews, 4, 4, CD008965, April 2014, 24718923, 6464969, 10.1002/14651858.CD008965.pub4,

Other

Smoking cessation and reducing indoor air pollution, such as that from cooking indoors with wood, crop residues or dung, are both recommended. Smoking appears to be the single biggest risk factor for pneumococcal pneumonia in otherwise-healthy adults. Hand hygiene and coughing into one’s sleeve may also be effective preventative measures. Wearing surgical masks by the sick may also prevent illness.Appropriately treating underlying illnesses (such as HIV/AIDS, diabetes mellitus, and malnutrition) can decrease the risk of pneumonia.WEB, Pneumonia (Fact sheet N°331),www.who.int/mediacentre/factsheets/fs331/en/, World Health Organization, August 2012, live,www.who.int/mediacentre/factsheets/fs331/en/," title="web.archive.org/web/20120830053348www.who.int/mediacentre/factsheets/fs331/en/,">web.archive.org/web/20120830053348www.who.int/mediacentre/factsheets/fs331/en/, 30 August 2012, WEB, Pneumonia Can Be Prevented – Vaccines Can Help,www.cdc.gov/features/Pneumonia/, Centers for Disease Control and Prevention, 22 October 2012, live,www.cdc.gov/features/Pneumonia/," title="web.archive.org/web/20121023024453www.cdc.gov/features/Pneumonia/,">web.archive.org/web/20121023024453www.cdc.gov/features/Pneumonia/, 23 October 2012, JOURNAL, Gray DM, Zar HJ, May 2010, Community-acquired pneumonia in HIV-infected children: a global perspective,journals.lww.com/co-pulmonarymedicine/Abstract/2010/05000/Community_acquired_pneumonia_in_HIV_infected.8.aspx, Current Opinion in Pulmonary Medicine, 16, 3, 208–16, 10.1097/MCP.0b013e3283387984, 20375782, 23778903, In children less than 6 months of age, exclusive breast feeding reduces both the risk and severity of disease. In people with HIV/AIDS and a CD4 count of less than 200 cells/uL the antibiotic trimethoprim/sulfamethoxazole decreases the risk of Pneumocystis pneumoniaJOURNAL, Huang L, Cattamanchi A, Davis JL, den Boon S, Kovacs J, Meshnick S, Miller RF, Walzer PD, Worodria W, Masur H, HIV-associated Pneumocystis pneumonia, Proceedings of the American Thoracic Society, 8, 3, 294–300, June 2011, 21653531, 3132788, 10.1513/pats.201009-062WR, and is also useful for prevention in those that are immunocompromised but do not have HIV.JOURNAL, Stern A, Green H, Paul M, Vidal L, Leibovici L, Prophylaxis for Pneumocystis pneumonia (PCP) in non-HIV immunocompromised patients, The Cochrane Database of Systematic Reviews, 10, 10, CD005590, October 2014, 25269391, 6457644, 10.1002/14651858.CD005590.pub3, Testing pregnant women for Group B Streptococcus and Chlamydia trachomatis, and administering antibiotic treatment, if needed, reduces rates of pneumonia in infants;JOURNAL, Taminato M, Fram D, Torloni MR, Belasco AG, Saconato H, Barbosa DA, Screening for group B Streptococcus in pregnant women: a systematic review and meta-analysis, Revista Latino-Americana de Enfermagem, 19, 6, 1470–78, November–December 2011, 22249684, 10.1590/s0104-11692011000600026, free, JOURNAL, Darville T, October 2005, Chlamydia trachomatis infections in neonates and young children,www.sciencedirect.com/science/article/abs/pii/S104518700500066X, Seminars in Pediatric Infectious Diseases, 16, 4, 235–44, 10.1053/j.spid.2005.06.004, 16210104, preventive measures for HIV transmission from mother to child may also be efficient.BOOK, Global Action Plan for Prevention and Control of Pneumonia (GAPP), 2009, World Health Organization,whqlibdoc.who.int/hq/2009/WHO_FCH_CAH_NCH_09.04_eng.pdf, live,whqlibdoc.who.int/hq/2009/WHO_FCH_CAH_NCH_09.04_eng.pdf," title="web.archive.org/web/20131017001256whqlibdoc.who.int/hq/2009/WHO_FCH_CAH_NCH_09.04_eng.pdf,">web.archive.org/web/20131017001256whqlibdoc.who.int/hq/2009/WHO_FCH_CAH_NCH_09.04_eng.pdf, 17 October 2013, Suctioning the mouth and throat of infants with meconium-stained amniotic fluid has not been found to reduce the rate of aspiration pneumonia and may cause potential harm,JOURNAL, Roggensack A, Jefferies AL, Farine D, April 2009, Management of meconium at birth,www.sciencedirect.com/science/article/abs/pii/S1701216316341536, Journal of Obstetrics and Gynaecology Canada, 31, 4, 353–54, 10.1016/s1701-2163(16)34153-6, 19497156, thus this practice is not recommended in the majority of situations. In the frail elderly good oral health care may lower the risk of aspiration pneumonia,JOURNAL, van der Maarel-Wierink CD, Vanobbergen JN, Bronkhorst EM, Schols JM, de Baat C, March 2013, Oral health care and aspiration pneumonia in frail older people: a systematic literature review,onlinelibrary.wiley.com/doi/10.1111/j.1741-2358.2012.00637.x, Gerodontology, 30, 1, 3–9, 10.1111/j.1741-2358.2012.00637.x, 22390255, even though there is no good evidence that one approach to mouth care is better than others in preventing nursing home acquired pneumonia.JOURNAL, Cao Y, Liu C, Lin J, Ng L, Needleman I, Walsh T, Li C, September 2018, Oral care measures for preventing nursing home-acquired pneumonia, The Cochrane Database of Systematic Reviews, 2022, 11, CD012416, 10.1002/14651858.CD012416.pub3, 9668328, 36383760, Zinc supplementation in children 2 months to five years old appears to reduce rates of pneumonia.JOURNAL, Lassi ZS, Moin A, Bhutta ZA, Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months, The Cochrane Database of Systematic Reviews, 12, CD005978, December 2016, 12, 27915460, 6463931, 10.1002/14651858.CD005978.pub3, For people with low levels of vitamin C in their diet or blood, taking vitamin C supplements may be suggested to decrease the risk of pneumonia, although there is no strong evidence of benefit. There is insufficient evidence to recommend that the general population take vitamin C to prevent or treat pneumonia.JOURNAL, Padhani ZA, Moazzam Z, Ashraf A, Bilal H, Salam RA, Das JK, Bhutta ZA, Vitamin C supplementation for prevention and treatment of pneumonia, The Cochrane Database of Systematic Reviews, 4, CD013134, 18 November 2021, 11, 34791642, 8599445, 10.1002/14651858.CD013134.pub3, For adults and children in the hospital who require a respirator, there is no strong evidence indicating a difference between heat and moisture exchangers and heated humidifiers for preventing pneumonia.JOURNAL, Gillies D, Todd DA, Foster JP, Batuwitage BT, Heat and moisture exchangers versus heated humidifiers for mechanically ventilated adults and children, The Cochrane Database of Systematic Reviews, 9, CD004711, September 2017, 12, 28905374, 6483749, 10.1002/14651858.CD004711.pub3, There is tentative evidence that laying flat on the back compared to semi-raised increases pneumonia risks in people who are intubated.JOURNAL, Wang L, Li X, Yang Z, Tang X, Yuan Q, Deng L, Sun X, Semi-recumbent position versus supine position for the prevention of ventilator-associated pneumonia in adults requiring mechanical ventilation, The Cochrane Database of Systematic Reviews, 1, CD009946, January 2016, 2016, 26743945, 7016937, 10.1002/14651858.CD009946.pub2, “>

Management{|class“wikitable” align“right” style@margin-left:0.4em;”

!colspan=2| CURB-65! Symptom !! PointsConfusion >1Urea>7 mmol/L >1Respiratory rate>30 >1Blood pressure>SBP