Community-acquired pneumonia causes: Difference between revisions
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{{Community-acquired pneumonia}} | {{Community-acquired pneumonia}} | ||
{{CMG}}; {{AE}} {{chetan}} | {{CMG}}; {{AE}} {{chetan}}; {{AL}} | ||
==Overview== | ==Overview== | ||
Community-acquired pneumonia can be caused by viral, bacterial, and fungal organisms. Causative etiology varies with age, immune status, epidemiologic background, and comorbidity. The most common cause of CAP in adult outpatients and inpatients is ''Streptococcus pneumoniae''. Patients admitted to the intensive care unit tend to have more aggressive organisms such as ''Staphylococcus aureus'' and Gram-negative bacilli. Neonates are most susceptible to Group-B-Streptococcus (GBS) which causes approximately 50% of pneumonias in the first week of life. Children and elderly patients are more susceptible to viral infections as well atypical bacterial pneumonias (Mycoplasma, Chlamydia, Legionella). | |||
==Causes== | ==Causes== | ||
===Most Common Etiologies for Community-Acquired Pneumonia <small><ref name="pmid17278083">{{cite journal |author=Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG |title=Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults |journal=[[Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America]] |volume=44 Suppl 2 |issue= |pages=S27–72 |year=2007 |month=March |pmid=17278083 |doi=10.1086/511159 |url=http://www.cid.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=17278083 |accessdate=2012-09-06}}</ref><ref name="Wong-2013">{{Cite journal | last1 = Wong | first1 = KK. | last2 = Fistek | first2 = M. | last3 = Watkins | first3 = RR. | title = Community-acquired pneumonia caused by Yersinia enterocolitica in an immunocompetent patient. | journal = J Med Microbiol | volume = 62 | issue = Pt 4 | pages = 650-1 | month = Apr | year = 2013 | doi = 10.1099/jmm.0.053488-0 | PMID = 23242642 }}</ref><ref name="Oh-2013">{{Cite journal | last1 = Oh | first1 = YJ. | last2 = Song | first2 = SH. | last3 = Baik | first3 = SH. | last4 = Lee | first4 = HH. | last5 = Han | first5 = IM. | last6 = Oh | first6 = DH. | title = A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea. | journal = Korean J Intern Med | volume = 28 | issue = 4 | pages = 486-90 | month = Jul | year = 2013 | doi = 10.3904/kjim.2013.28.4.486 | PMID = 23864808 }}</ref></small>=== | |||
{| style="border: 0px; font-size: 85%; margin: 3px; width:700px;" align=center | |||
|valign=top| | |||
|+ | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Outpatient | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Inpatient (non-ICU) | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Inpatient (ICU) | |||
|- | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
#[[Streptococcus pneumoniae]] | |||
#[[Mycoplasma pneumoniae]] | |||
#[[Haemophilus influenzae]] | |||
#[[Chlamydophila pneumoniae]] | |||
#[[Influenza|Influenza A and B]], [[adenovirus]], [[respiratory syncytial virus]], [[parainfluenza]] | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
#[[Streptococcus pneumoniae]] | |||
#[[Mycoplasma pneumoniae]] | |||
#[[Haemophilus influenzae]] | |||
#[[Legionella]] | |||
#[[Aspiration]] | |||
#[[Influenza|Influenza A and B]], [[adenovirus]], [[respiratory syncytial virus]], [[parainfluenza]] | |||
#[[Yersinia enterocolitica]] | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
#[[Streptococcus pneumoniae]] | |||
#[[Staphylococcus aureus]] | |||
#[[Legionella]] | |||
#[[Gram-negative bacilli]] | |||
#[[Haemophilus influenzae]] | |||
#[[Acinetobacter baumannii]] | |||
|} | |||
===Common Causes by Age Group=== | |||
{| style="border: 0px; font-size: 85%; margin: 3px; width:700px;" align=center | |||
|valign=top| | |||
|+ | |||
! style="background: #4479BA; color:#FFF; width: 100px;" | Age Group | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Neonates | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Children | |||
! style="background: #4479BA; color:#FFF; width: 250px;" | Adults | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;font-weight: bold" | Bacteria | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
# ''[[Listeria monocytogenes]]'' | |||
# ''[[Mycobacterium tuberculosis]]'' | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
# ''[[Mycoplasma pneumoniae]]'' | |||
# ''[[Chlamydophila pneumoniae]]'' | |||
# ''[[Legionella pneumophila]]'' | |||
# ''[[Chlamydia trachomatis]]'' | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
'''Typical Bacteria''' | |||
# ''[[Streptococcus pneumoniae]]'' | |||
# ''[[Haemophilus influenzae]]'' | |||
# ''[[Escherichia coli]]'' | |||
# ''[[Klebsiella pneumoniae]]'' | |||
# ''[[Pseudomonas aeruginosa]]'' | |||
'''Atypical Bacteria''' | |||
# ''[[Mycoplasma pneumoniae]]'' | |||
# ''[[Chlamydophila pneumoniae]]'' | |||
# ''[[Legionella pneumophila]]'' | |||
|- | |||
| style="padding: 5px 5px; background: #DCDCDC;font-weight: bold" | Virus | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
# [[Herpes simplex virus]] | |||
# [[Adenovirus]] | |||
# [[Mumps]] | |||
# [[Enterovirus]] | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
# [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]] | |||
# [[Metapneumovirus]] | |||
# [[Adenovirus]] | |||
# [[Parainfluenza]] | |||
# [[Influenza]] | |||
# [[Rhinovirus]] | |||
| style="padding: 5px 5px; background: #F5F5F5;" | | |||
# [[Influenza]] | |||
# [[Parainfluenza]] | |||
# [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]] | |||
# [[Metapneumovirus]] | |||
# [[Adenovirus]] | |||
|} | |||
* Newborn [[infant]]s, [[children]], and [[adult]]s are at risk for different spectrums of disease causing microorganisms. | * Newborn [[infant]]s, [[children]], and [[adult]]s are at risk for different spectrums of disease causing microorganisms. | ||
* In addition, adults with [[chronic (medicine)|chronic]] illnesses, who live in certain parts of the world, who reside in [[nursing home]]s, who have recently been treated with [[antibiotic]]s, or who are [[alcoholism|alcoholics]] are at risk for unique infections. | * In addition, adults with [[chronic (medicine)|chronic]] illnesses, who live in certain parts of the world, who reside in [[nursing home]]s, who have recently been treated with [[antibiotic]]s, or who are [[alcoholism|alcoholics]] are at risk for unique infections. | ||
=== | ===Infants and Newborns=== | ||
* GBS causes at least 50% of cases of CAP in the first week of life.{{ref|Webber}} | * GBS causes at least 50% of cases of CAP in the first week of life.{{ref|Webber}} | ||
* Other bacterial causes in the newborn period include ''[[Listeria monocytogenes]]'' and [[tuberculosis]] | * Other bacterial causes in the newborn period include ''[[Listeria monocytogenes]]'' and ''[[Mycobacterium tuberculosis]]''. | ||
* Viral causes like [[herpes simplex virus]] (most common) [[adenovirus]], [[mumps]], and [[enterovirus]] | * Viral causes like [[herpes simplex virus]] (most common), [[adenovirus]], [[mumps]], and [[enterovirus]]. | ||
===Children=== | ===Children=== | ||
* For the most part, children older than one month are at risk for the same microorganisms as adults. | * For the most part, children older than one month are at risk for the same microorganisms as adults. | ||
* | * Children less than five years are much less likely to have pneumonia caused by ''[[Mycoplasma pneumoniae]]'', ''[[Chlamydophila pneumoniae]]'', or ''[[Legionella|Legionella pneumophila]]''.<ref name="Shachor-Meyouhas-2012">{{Cite journal | last1 = Shachor-Meyouhas | first1 = Y. | last2 = Arad-Cohen | first2 = N. | last3 = Zaidman | first3 = I. | last4 = Gefen | first4 = A. | last5 = Kassis | first5 = I. | title = [Legionella pneumonia in a child with leukemia]. | journal = Harefuah | volume = 151 | issue = 8 | pages = 479-82, 496 | month = Aug | year = 2012 | doi = | PMID = 23350295 }}</ref> | ||
* In contrast, older children and teenagers are more likely to acquire ''[[ | * In contrast, older children and teenagers are more likely to acquire ''[[Mycoplasma pneumoniae]]'' and ''[[Chlamydophila pneumoniae]]'' than adults.{{ref|Wubbel}} | ||
* A unique cause of CAP in this group is ''[[ | * A unique cause of CAP in this group is ''[[Chlamydia trachomatis]]'', which is acquired during birth but does not cause pneumonia until 2-4 weeks later. | ||
* Common viruses include [[respiratory syncytial virus | * Common viruses include [[respiratory syncytial virus|respiratory syncytial virus (RSV)]], [[metapneumovirus]], [[adenovirus]], [[parainfluenza]], [[influenza]], and [[rhinovirus]]. | ||
* RSV in particular is a common source of illness and hospitalization.{{ref|Abzug}} | * [[RSV]] in particular is a common source of illness and hospitalization.{{ref|Abzug}} | ||
* Fungi and parasites are not typically encountered in otherwise healthy infants, though maternally-derived [[syphilis]] can be a cause of CAP in this age group. | * Fungi and parasites are not typically encountered in otherwise healthy infants, though maternally-derived [[syphilis]] can be a cause of CAP in this age group. | ||
===Adults=== | ===Adults=== | ||
====Viruses==== | The causes of CAP in adults are outlined in the following categories. | ||
* Viruses | ======Viruses====== | ||
* Viruses account for about 20% cases of CAP. | |||
* Common viruses are [[influenza]], [[parainfluenza]], [[respiratory syncytial virus]], [[metapneumovirus]], and [[adenovirus]]. | * Common viruses are [[influenza]], [[parainfluenza]], [[respiratory syncytial virus]], [[metapneumovirus]], and [[adenovirus]]. | ||
* Less common viruses include [[varicella|chicken pox]], [[SARS]], [[H5N1|avian flu]], and [[hantavirus]].{{ref|Roux}} | * Less common viruses include [[varicella|chicken pox]], [[SARS]], [[H5N1|avian flu]], and [[hantavirus]].{{ref|Roux}} | ||
====Streptococcus | ======''Streptococcus pneumoniae''====== | ||
* '' | |||
* Aspiration pneumonia is most commonly caused by anaerobic organisms. | * ''[[Streptococcus pneumoniae]]'' is the most common cause of community-acquired pneumonia. | ||
* [[Aspiration pneumonia]] is most commonly caused by [[anaerobic]] organisms. | |||
* Prior to the development of antibiotics and vaccination, it was a leading cause of death. | * Prior to the development of antibiotics and vaccination, it was a leading cause of death. | ||
* Traditionally, it was highly sensitive to [[penicillin]], but during the | * Traditionally, it was highly sensitive to [[penicillin]], but during the 1970s resistance to multiple antibiotics began to develop. | ||
* Current strains of | * Current strains of drug resistant ''[[Streptococcus pneumoniae]]'' (DRSP) are common, accounting for twenty percent of all [[streptococcal]] infections. | ||
* | * risk factors for DRSP in adults include: being older than 65, having exposure to children in day care, [[alcoholism]], other severe underlying disease, or recent treatment with antibiotics; individuals exposed to these risk factors should initially be treated with antibiotics effective against DRSP.{{ref|Ruhe}} | ||
====Special Situations==== | ======Atypical Organisms====== | ||
* Coccidioides are common in southwestern | * ''[[Mycoplasma pneumoniae]]'', ''[[Chlamydophila pneumoniae]]'', and ''[[Legionella|Legionella pneumophila]]'' are often grouped as atypical pneumonia. Community-acquired pneumonia caused by these agents present insidiously, with a non-productive [[cough]] and prominent extra-pulmonary complaints, such as [[myalgia]]s and [[diarrhea]] (lack the typical [[pneumonia]] symptoms of [[fever]], [[cough]], and [[sputum]]). | ||
* Anaerobic infection is common in alcoholics. Pneumococcal pneumonia remains the most common cause of CAP in alcoholics | |||
* [[Psittacosis]] ( | * ''[[Mycoplasma pneumoniae]]'' is often referred to as "walking pneumonia." It is transmitted via respiratory droplets and is common among healthy individuals in close contact with one another in settings such as dormitories or military barracks. | ||
* [[Anaerobes]] are common in patients with poor dental hygiene | |||
* [[Streptococcus | * Atypical organisms are more difficult to grow and respond to different antibiotics; they were discovered more recently than the typical bacteria discovered in the early twentieth century. | ||
* [[ | |||
* [[ | ======''Haemophilus influenzae''====== | ||
* In patients with structural lung disease such as [[bronchiectasis]] and [[cystic fibrosis]], [[ | |||
==Aspiration Pneumonia | * ''[[Haemophilus influenzae]]'' used to be a common bacterial cause of CAP. | ||
* Incompetent [[swallowing]] mechanism, | * First discovered in 1892, it was initially believed to be the cause of [[influenza]] because it commonly causes CAP in people who have suffered recent lung damage from viral pneumonia. | ||
======Enteric Gram-Negative Bacteria====== | |||
* Enteric bacteria such as ''[[Escherichia coli]]'' and ''[[Klebsiella pneumoniae]]'' may cause commnity-acquired penumonia. | |||
* risk factors in adults for infection include: living in a [[nursing home]], serious [[heart disease|heart]] and [[lung disease]], and recent antibiotic use; these individuals should initially be treated with antibiotics effective against enteric Gram-negative bacteria. | |||
======''Pseudomonas aeruginosa''====== | |||
* ''[[Pseudomonas aeruginosa]]'' is an uncommon cause of CAP, but it is a particularly difficult bacteria to treat. | |||
* Individuals who are malnourished, have [[bronchiectasis]], are on [[corticosteroids]], or have recently had strong antibiotics for a week or more, should initially be treated with antibiotics effective against ''[[Pseudomonas aeruginosa]]''.{{ref|Lieberman}} | |||
======Special Situations====== | |||
* [[Coccidioidomycosis|Coccidioides spp.]] are common in southwestern area of the United States. | |||
* [[Anaerobic]] infection is common in alcoholics. [[Pneumococcal]] pneumonia remains the most common cause of CAP in alcoholics. | |||
* [[Psittacosis]] (caused by ''[[Chlamydophila psittaci]]'') should be considered in the patient with exposure to birds or bird droppings. | |||
* [[Anaerobes]] are common in patients with poor dental hygiene and a suspected large volume of aspiration. | |||
* ''[[Streptococcus pneumoniae]]'', ''[[Haemophilus influenzae]]'', ''[[Moraxella catarrhalis]]'', and ''[[Legionella]]'' species are the common causes of community acquired pneumonia in those with chronic obstructive pulmonary disorders and smokers. | |||
* ''[[Streptococcus pneumoniae]]'', [[Gram-negative bacilli]], ''[[Haemophilus influenzae]]'', ''[[Staphylococcus aureus]]'', [[anaerobe]]s, and ''[[Chlamydophila pneumoniae]]'' are more common in nursing home residents. | |||
* ''[[Streptococcus pneumoniae]]'', ''[[Haemophilus influenzae]]'', and ''[[Mycobacterium tuberculosis]]'' are common pathogens in early stages of [[HIV]], whereas, ''[[Pneumocystis jiroveci]]'', ''[[Histoplasma]]'', and ''[[Cryptococcus]]'' are commonly seen in late stages [[HIV]]. | |||
* In patients with structural lung disease such as [[bronchiectasis]] and [[cystic fibrosis]], ''[[Pseudomonas aeruginosa]]'', ''[[Burkholderia cepacia]]'', and ''[[Staphylococcus aureus]]'' are the common pathogens involved. | |||
======Aspiration Pneumonia====== | |||
* Incompetent [[swallowing]] mechanism, as can be found in neurological disease (a common cause being [[cerebrovascular accident|strokes]]) or while a person is [[Drunkenness|intoxicated]]. | |||
* [[Iatrogenic]] causes such as [[general anaesthesia]] for an [[Surgery|operation]]. Patients are therefore instructed to be [[nil per os]] (NPO) for at least four hours before surgery. | * [[Iatrogenic]] causes such as [[general anaesthesia]] for an [[Surgery|operation]]. Patients are therefore instructed to be [[nil per os]] (NPO) for at least four hours before surgery. | ||
* Whether aspiration pneumonia represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy. | * Whether [[aspiration pneumonia]] represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy. | ||
== | |||
{{ | ===Causes by Organ System=== | ||
=== | |||
{|style="width:80%; height:100px" border="1" | |||
|style="height:100px"; style="width:25%" border="1" bgcolor="LightSteelBlue" |'''Cardiovascular''' | |||
|style="height:100px"; style="width:75%" border="1" bgcolor="Beige" | No underlying causes | |||
|- | |||
|bgcolor="LightSteelBlue"| '''Chemical/Poisoning''' | |||
|bgcolor="Beige"| No underlying cause | |||
|-bgcolor="LightSteelBlue" | |||
| '''Dental''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Dermatologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Drug Side Effect''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Ear Nose Throat''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Endocrine''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Environmental''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Gastroenterologic''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Genetic''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Hematologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Iatrogenic''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Infectious Disease''' | |||
|bgcolor="Beige"| [[Acinetobacter baumannii]], [[Actinomycosis]], [[Adenovirus|Adenovirus (serotype 1, 2, 3, 4, 5, 7, 14, 21, 35)]], [[AIDS|AIDS-related opportunistic infections]], [[Aspergillosis]], [[Aspiration]], [[Bacillus anthracis]], [[Bird flu|Bird flu (avian influenza)]], [[Blastomycosis]], [[Burkholderia cepacia]], [[Burkholderia pseudomallei]], [[Chlamydophila pneumoniae]], [[Chickenpox]], [[Coccidioides immitis]], [[Coronavirus]], [[Coxiella burnetii|Coxiella burnetii (Q fever)]], [[Cryptococcus neoformans]], [[Cytomegalovirus]], [[Escherichia coli]], [[Enterovirus]], [[Francisella tularensis]], [[Gram-negative bacilli]], [[Haemophilus influenzae]], [[Influenza A virus subtype H1N1|H1N1 flu]], [[Hantavirus]], [[Herpes simplex virus]], [[Histoplasma capsulatum]], [[Histoplasmosis]], [[Human bocavirus]], [[parechovirus|Human parechovirus types 1, 2, and 3]], [[Influenza]], [[Klebsiella pneumoniae]], [[Legionella micdadei]], [[Legionella pneumophila|Legionella pneumophila (Legionnaires' disease)]], [[Listeria monocytogenes]], [[Mycoplasma pneumoniae]], [[Measles]], [[Melioidosis]], [[Metapneumovirus]], [[Middle East respiratory syndrome coronavirus]], [[Moraxella catarrhalis]], [[Mumps]], [[Mycobacterium avium-intracellulare]], [[Mycobacterium haemophilum]], [[Mycobacterium kansasii]], [[Neisseria meningitidis]], [[Coronavirus|New Haven coronavirus]], [[Nocardia]], [[Paragonimiasis]], [[Parainfluenza]], [[Pneumocystis jiroveci]], [[Pneumonic plague]], [[Proteus]], [[Pseudomonas aeruginosa]], [[Chlamydophila psittaci|Chlamydophila psittaci (psittacosis)]], [[Rat-bite fever]], [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]], [[Rhinovirus]], [[Rhodococcus equi]], [[Streptococcus pneumoniae|Streptococcus pneumoniae (pneumococcus)]], [[SARS]], [[Serratia]], [[Severe acute respiratory syndrome]], [[Sporotrichosis ]], [[Staphylococcus aureus]], [[Streptococcus agalactiae|Streptococcus agalactiae (group B streptococcus)]], [[Streptococcus pyogenes|Streptococcus pyogenes (group A streptococcus)]], [[Streptococcus pneumoniae]], [[Swine flu]], [[Toxocariasis ]], [[Toxoplasma gondii]], [[Trichosporon ]], [[Trypanosomiasis]], [[Typhus]], [[Varicella-zoster virus]], [[Yersinia enterocolitica]], [[Yersinia pestis]], [[Zygomycosis]] | |||
|-bgcolor="LightSteelBlue" | |||
| '''Musculoskeletal/Orthopedic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Neurologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Nutritional/Metabolic''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Obstetric/Gynecologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Oncologic''' | |||
|bgcolor="Beige"| No underlying cause | |||
|-bgcolor="LightSteelBlue" | |||
| '''Ophthalmologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Overdose/Toxicity''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Psychiatric''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Pulmonary''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Renal/Electrolyte''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Rheumatology/Immunology/Allergy''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Sexual''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Trauma''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Urologic''' | |||
|bgcolor="Beige"| No underlying causes | |||
|- | |||
|-bgcolor="LightSteelBlue" | |||
| '''Miscellaneous''' | |||
|bgcolor="Beige"| No underlying cause | |||
|- | |||
|} | |||
===Causes in Alphabetical Order=== | |||
{{col-begin|width=80%}} | |||
{{col-break|width=33%}} | |||
* [[Acinetobacter baumannii]] | |||
* [[Actinomycosis]] | |||
* [[Adenovirus|Adenovirus (serotype 1, 2, 3, 4, 5, 7, 14, 21, 35)]] | |||
* [[AIDS|AIDS-related opportunistic infections]] | |||
* [[Aspergillosis]] | |||
* [[Aspiration]] | |||
* [[Bacillus anthracis]] | |||
* [[Bird flu|Bird flu (avian influenza)]] | |||
* [[Blastomycosis]] | |||
* [[Burkholderia cepacia]] | |||
* [[Burkholderia pseudomallei]] | |||
* [[Chlamydophila pneumoniae]] | |||
* [[Chickenpox]] | |||
* [[Coccidioides immitis]] | |||
* [[Coronavirus]] | |||
* [[Coxiella burnetii|Coxiella burnetii (Q fever)]] | |||
* [[Cryptococcus neoformans]] | |||
* [[Cytomegalovirus]] | |||
* [[Escherichia coli]] | |||
* [[Enterovirus]] | |||
* [[Francisella tularensis]] | |||
* [[Gram-negative bacilli]] | |||
* [[Influenza A virus subtype H1N1|H1N1 flu]] | |||
* [[Haemophilus influenzae]] | |||
* [[Hantavirus]] | |||
* [[Herpes simplex virus]] | |||
* [[Histoplasma capsulatum]] | |||
{{col-break|width=33%}} | |||
* [[Histoplasmosis]] | |||
* [[Human bocavirus]] | |||
* [[parechovirus|Human parechovirus types 1, 2, and 3]] | |||
* [[Influenza]] | |||
* [[Klebsiella pneumoniae]] | |||
* [[Legionella micdadei]] | |||
* [[Legionella pneumophila|Legionella pneumophila (Legionnaires' disease)]] | |||
* [[Listeria monocytogenes]] | |||
* [[Mycoplasma pneumoniae]] | |||
* [[Measles]] | |||
* [[Melioidosis]] | |||
* [[Metapneumovirus]] | |||
* [[Middle East respiratory syndrome coronavirus]] | |||
* [[Moraxella catarrhalis]] | |||
* [[Mumps]] | |||
* [[Mycobacterium avium-intracellulare]] | |||
* [[Mycobacterium haemophilum]] | |||
* [[Mycobacterium kansasii]] | |||
* [[Mycoplasma pneumoniae]] | |||
* [[Neisseria meningitidis]] | |||
* [[Coronavirus|New Haven coronavirus]] | |||
* [[Nocardia]] | |||
* [[Paragonimiasis]] | |||
* [[Parainfluenza]] | |||
* [[Pneumocystis jiroveci]] | |||
* [[Pneumonic plague]] | |||
{{col-break|width=33%}} | |||
* [[Proteus]] | |||
* [[Pseudomonas aeruginosa]] | |||
* [[Chlamydophila psittaci|Chlamydophila psittaci (psittacosis)]] | |||
* [[Rat-bite fever]] | |||
* [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]] | |||
* [[Rhinovirus]] | |||
* [[Rhodococcus equi]] | |||
* [[Streptococcus pneumoniae|Streptococcus pneumoniae (pneumococcus)]] | |||
* [[SARS]] | |||
* [[Serratia]] | |||
* [[Severe acute respiratory syndrome]] | |||
* [[Sporotrichosis ]] | |||
* [[Staphylococcus aureus]] | |||
* [[Streptococcus agalactiae|Streptococcus agalactiae (group B streptococcus)]] | |||
* [[Streptococcus pyogenes|Streptococcus pyogenes (group A streptococcus)]] | |||
* [[Streptococcus pneumoniae]] | * [[Streptococcus pneumoniae]] | ||
* [[ | |||
* [[ | * [[Swine flu]] | ||
* [[ | |||
* [[ | * [[Toxocariasis ]] | ||
* | * [[Toxoplasma gondii]] | ||
* | * [[Trichosporon ]] | ||
* | * [[Trypanosomiasis]] | ||
* [[Typhus]] | |||
* Yersinia enterocolitica | |||
* [[Varicella-zoster virus]] | |||
* | |||
* [[Yersinia enterocolitica]] | |||
* | |||
* [[Yersinia pestis]] | |||
* [[Zygomycosis]] | |||
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==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
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[[Category:Disease]] | [[Category:Disease]] | ||
[[Category:Pulmonology]] | [[Category:Pulmonology]] | ||
[[Category:Pneumonia|Pneumonia]] | [[Category:Pneumonia|Pneumonia]] | ||
[[Category:Emergency medicine]] | [[Category:Emergency medicine]] | ||
Latest revision as of 21:01, 29 July 2020
Community-Acquired Pneumonia Microchapters |
Differentiating Community-acquired pneumonia from other Diseases |
Diagnosis |
Treatment |
Case Studies |
Community-acquired pneumonia causes On the Web |
American Roentgen Ray Society Images of Community-acquired pneumonia causes |
Directions to Hospitals Treating Community-acquired pneumonia |
Risk calculators and risk factors for Community-acquired pneumonia causes |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Chetan Lokhande, M.B.B.S [2]; Alejandro Lemor, M.D. [3]
Overview
Community-acquired pneumonia can be caused by viral, bacterial, and fungal organisms. Causative etiology varies with age, immune status, epidemiologic background, and comorbidity. The most common cause of CAP in adult outpatients and inpatients is Streptococcus pneumoniae. Patients admitted to the intensive care unit tend to have more aggressive organisms such as Staphylococcus aureus and Gram-negative bacilli. Neonates are most susceptible to Group-B-Streptococcus (GBS) which causes approximately 50% of pneumonias in the first week of life. Children and elderly patients are more susceptible to viral infections as well atypical bacterial pneumonias (Mycoplasma, Chlamydia, Legionella).
Causes
Most Common Etiologies for Community-Acquired Pneumonia [1][2][3]
Outpatient | Inpatient (non-ICU) | Inpatient (ICU) |
---|---|---|
Common Causes by Age Group
Age Group | Neonates | Children | Adults |
---|---|---|---|
Bacteria |
Typical Bacteria
Atypical Bacteria | ||
Virus |
- Newborn infants, children, and adults are at risk for different spectrums of disease causing microorganisms.
- In addition, adults with chronic illnesses, who live in certain parts of the world, who reside in nursing homes, who have recently been treated with antibiotics, or who are alcoholics are at risk for unique infections.
Infants and Newborns
- GBS causes at least 50% of cases of CAP in the first week of life.[4]
- Other bacterial causes in the newborn period include Listeria monocytogenes and Mycobacterium tuberculosis.
- Viral causes like herpes simplex virus (most common), adenovirus, mumps, and enterovirus.
Children
- For the most part, children older than one month are at risk for the same microorganisms as adults.
- Children less than five years are much less likely to have pneumonia caused by Mycoplasma pneumoniae, Chlamydophila pneumoniae, or Legionella pneumophila.[4]
- In contrast, older children and teenagers are more likely to acquire Mycoplasma pneumoniae and Chlamydophila pneumoniae than adults.[5]
- A unique cause of CAP in this group is Chlamydia trachomatis, which is acquired during birth but does not cause pneumonia until 2-4 weeks later.
- Common viruses include respiratory syncytial virus (RSV), metapneumovirus, adenovirus, parainfluenza, influenza, and rhinovirus.
- RSV in particular is a common source of illness and hospitalization.[6]
- Fungi and parasites are not typically encountered in otherwise healthy infants, though maternally-derived syphilis can be a cause of CAP in this age group.
Adults
The causes of CAP in adults are outlined in the following categories.
Viruses
- Viruses account for about 20% cases of CAP.
- Common viruses are influenza, parainfluenza, respiratory syncytial virus, metapneumovirus, and adenovirus.
- Less common viruses include chicken pox, SARS, avian flu, and hantavirus.[7]
Streptococcus pneumoniae
- Streptococcus pneumoniae is the most common cause of community-acquired pneumonia.
- Aspiration pneumonia is most commonly caused by anaerobic organisms.
- Prior to the development of antibiotics and vaccination, it was a leading cause of death.
- Traditionally, it was highly sensitive to penicillin, but during the 1970s resistance to multiple antibiotics began to develop.
- Current strains of drug resistant Streptococcus pneumoniae (DRSP) are common, accounting for twenty percent of all streptococcal infections.
- risk factors for DRSP in adults include: being older than 65, having exposure to children in day care, alcoholism, other severe underlying disease, or recent treatment with antibiotics; individuals exposed to these risk factors should initially be treated with antibiotics effective against DRSP.[8]
Atypical Organisms
- Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila are often grouped as atypical pneumonia. Community-acquired pneumonia caused by these agents present insidiously, with a non-productive cough and prominent extra-pulmonary complaints, such as myalgias and diarrhea (lack the typical pneumonia symptoms of fever, cough, and sputum).
- Mycoplasma pneumoniae is often referred to as "walking pneumonia." It is transmitted via respiratory droplets and is common among healthy individuals in close contact with one another in settings such as dormitories or military barracks.
- Atypical organisms are more difficult to grow and respond to different antibiotics; they were discovered more recently than the typical bacteria discovered in the early twentieth century.
Haemophilus influenzae
- Haemophilus influenzae used to be a common bacterial cause of CAP.
- First discovered in 1892, it was initially believed to be the cause of influenza because it commonly causes CAP in people who have suffered recent lung damage from viral pneumonia.
Enteric Gram-Negative Bacteria
- Enteric bacteria such as Escherichia coli and Klebsiella pneumoniae may cause commnity-acquired penumonia.
- risk factors in adults for infection include: living in a nursing home, serious heart and lung disease, and recent antibiotic use; these individuals should initially be treated with antibiotics effective against enteric Gram-negative bacteria.
Pseudomonas aeruginosa
- Pseudomonas aeruginosa is an uncommon cause of CAP, but it is a particularly difficult bacteria to treat.
- Individuals who are malnourished, have bronchiectasis, are on corticosteroids, or have recently had strong antibiotics for a week or more, should initially be treated with antibiotics effective against Pseudomonas aeruginosa.[9]
Special Situations
- Coccidioides spp. are common in southwestern area of the United States.
- Anaerobic infection is common in alcoholics. Pneumococcal pneumonia remains the most common cause of CAP in alcoholics.
- Psittacosis (caused by Chlamydophila psittaci) should be considered in the patient with exposure to birds or bird droppings.
- Anaerobes are common in patients with poor dental hygiene and a suspected large volume of aspiration.
- Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, and Legionella species are the common causes of community acquired pneumonia in those with chronic obstructive pulmonary disorders and smokers.
- Streptococcus pneumoniae, Gram-negative bacilli, Haemophilus influenzae, Staphylococcus aureus, anaerobes, and Chlamydophila pneumoniae are more common in nursing home residents.
- Streptococcus pneumoniae, Haemophilus influenzae, and Mycobacterium tuberculosis are common pathogens in early stages of HIV, whereas, Pneumocystis jiroveci, Histoplasma, and Cryptococcus are commonly seen in late stages HIV.
- In patients with structural lung disease such as bronchiectasis and cystic fibrosis, Pseudomonas aeruginosa, Burkholderia cepacia, and Staphylococcus aureus are the common pathogens involved.
Aspiration Pneumonia
- Incompetent swallowing mechanism, as can be found in neurological disease (a common cause being strokes) or while a person is intoxicated.
- Iatrogenic causes such as general anaesthesia for an operation. Patients are therefore instructed to be nil per os (NPO) for at least four hours before surgery.
- Whether aspiration pneumonia represents a true bacterial infection or a chemical inflammatory process remains the subject of significant controversy.
Causes by Organ System
Causes in Alphabetical Order
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References
- ↑ Mandell LA, Wunderink RG, Anzueto A, Bartlett JG, Campbell GD, Dean NC, Dowell SF, File TM, Musher DM, Niederman MS, Torres A, Whitney CG (2007). "Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults". Clinical Infectious Diseases : an Official Publication of the Infectious Diseases Society of America. 44 Suppl 2: S27–72. doi:10.1086/511159. PMID 17278083. Retrieved 2012-09-06. Unknown parameter
|month=
ignored (help) - ↑ Wong, KK.; Fistek, M.; Watkins, RR. (2013). "Community-acquired pneumonia caused by Yersinia enterocolitica in an immunocompetent patient". J Med Microbiol. 62 (Pt 4): 650–1. doi:10.1099/jmm.0.053488-0. PMID 23242642. Unknown parameter
|month=
ignored (help) - ↑ Oh, YJ.; Song, SH.; Baik, SH.; Lee, HH.; Han, IM.; Oh, DH. (2013). "A case of fulminant community-acquired Acinetobacter baumannii pneumonia in Korea". Korean J Intern Med. 28 (4): 486–90. doi:10.3904/kjim.2013.28.4.486. PMID 23864808. Unknown parameter
|month=
ignored (help) - ↑ Shachor-Meyouhas, Y.; Arad-Cohen, N.; Zaidman, I.; Gefen, A.; Kassis, I. (2012). "[Legionella pneumonia in a child with leukemia]". Harefuah. 151 (8): 479–82, 496. PMID 23350295. Unknown parameter
|month=
ignored (help)