Community-acquired pneumonia causes: Difference between revisions

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__NOTOC__
__NOTOC__
{{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.
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).


==General Considerations==
==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.
 
* 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===
===Infants and Newborns===
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* 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.
* 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|respiratory syncytial virus (RSV)]], [[metapneumovirus]], [[adenovirus]], [[parainfluenza]], [[influenza]], and [[rhinovirus]].
* 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===
 
The causes of CAP in adults are outlined in the following categories.
======Viruses======
======Viruses======


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* 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}}
======Atypical Organisms======
* ''[[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 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, such as dormitories or military barracks.
* Atypical organisms are more difficult to grow, respond to different antibiotics, and were discovered more recently than the typical bacteria discovered in the early twentieth century.


======''Streptococcus pneumoniae''======
======''Streptococcus pneumoniae''======


* ''[[Streptococcus pneumoniae]]'' is the most common cause of community-acquired pneumonia.
* ''[[Streptococcus pneumoniae]]'' is the most common cause of community-acquired pneumonia.
* Aspiration pneumonia is most commonly caused by anaerobic organisms.
* [[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 1970s resistance to multiple antibiotics began to develop.
* 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" or DRSP are common, accounting for twenty percent of all streptococcal infections.
* Current strains of drug resistant ''[[Streptococcus pneumoniae]]'' (DRSP) are common, accounting for twenty percent of all [[streptococcal]] infections.
* Adults with risk factors for DRSP including being older than 65, having exposure to children in [[day care]], [[alcoholism]], other severe underlying disease, or recent treatment with antibiotics should initially be treated with antibiotics effective against DRSP.{{ref|Ruhe}}
* 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}}
 
======Atypical Organisms======
* ''[[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]]).
 
* ''[[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''======


* ''Haemophilus influenzae'' used to be a common bacterial cause of CAP.
* ''[[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.
* 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 Gram-Negative Bacteria======


* Enteric bacteria such as ''[[Escherichia coli]]'' and ''[[Klebsiella pneumoniae]]'' may cause commnity-acquired penumonia.
* Enteric bacteria such as ''[[Escherichia coli]]'' and ''[[Klebsiella pneumoniae]]'' may cause commnity-acquired penumonia.
* Adults with risk factors for infection, which include living in a [[nursing home]], serious [[heart disease|heart]] and [[lung disease]], and recent antibiotic use should initially be treated with antibiotics effective against Enteric Gram negative bacteria.
* 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''======


* ''[[Pseudomonas aeruginosa]]'' is an uncommon cause of CAP, but it is a particularly difficult bacteria to treat.
* ''[[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}}
* 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======
======Special Situations======


* [[Coccidioides|Coccidioides spp.]] are common in southwestern area of the United States.
* [[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 too.
* [[Anaerobic]] infection is common in alcoholics. [[Pneumococcal]] pneumonia remains the most common cause of CAP in alcoholics.
* [[Psittacosis]] (due to [[Chlamydophila psittaci]]) should be considered in the patient with exposure to birds or bird droppings.
* [[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.
* [[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 [[chronic obstructive pulmonary disorders]] and [[smokers]].
* ''[[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]]'', [[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.
* ''[[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.
* 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======
======Aspiration Pneumonia======


* Incompetent [[swallowing]] mechanism, such as in neurological disease (a common cause being [[cerebrovascular accident|strokes]]) or while a person is [[Drunkenness|intoxicated]].
* 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.
==Infectious Diseases Society of America/American Thoracic Society consensus statement on common etiologies of community-acquired pneumonia in adults.<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}}</ref> (DO NOT EDIT)==
 
{| style="border: 2px solid #696969;" align="center"
|+ <SMALL>''Etiology of community-acquired pneumonia.''</SMALL>
| style="background: #A5B2D6; border: 0px solid #696969; padding: 0 5px; width: 200px"| '''Location''' || style="background: #A5B2D6; border: 0px solid #696969; padding: 0 5px; width: 200px" | '''Etiology of community acquired pneumonia'''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;▸&nbsp;'''''Outpatient''''' || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸  '''''Streptococcus pneumoniae'''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸  '''''Mycoplasma pneumoniae'''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸  '''''Haemophilus influenzae'''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸  '''''Chlamydophila pneumoniae'''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''Respiratory viruses'''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;▸&nbsp;'''''Inpatient (non-ICU)''''' || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''S. pneumoniae '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''M. pneumoniae  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''C. pneumoniae  ''''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''H. influenzae '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''Legionella species  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''Aspiration  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ ''''' Respiratory viruses  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left | ▸ '''''Yersinia enterocolitica  '''''<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>
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;▸&nbsp;'''''Inpatient (ICU)''''' || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''S. pneumoniae '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''Staphylococcus aureus  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''Legionella species '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp; || style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''Gram-negative bacilli  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''H. influenzae  '''''
|-
| style="font-size: 90%; padding: 0 5px; background: #F5F5F5" align=left |&nbsp;&nbsp;|| style="font-size: 90%; padding: 0 5px; background: #DCDCDC" align=left |▸ '''''Acinetobacter baumannii '''''<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>
|-
|}
 
==Causes==
 
===Common Causes===
 
=====Neonates=====
 
* Bacteria
# ''[[Listeria monocytogenes]]''
# ''[[Mycobacterium tuberculosis]]''
 
* Viruses
# [[Herpes simplex virus]]
# [[Adenovirus]]
# [[Mumps]]
# [[Enterovirus]]
 
=====Children=====
 
* Bacteria
# ''[[Mycoplasma pneumoniae]]''
# ''[[Chlamydophila pneumoniae]]''
# ''[[Legionella pneumophila]]''
# ''[[Chlamydia trachomatis]]''
 
* Viruses
# [[Respiratory syncytial virus|Respiratory syncytial virus (RSV)]]
# [[Metapneumovirus]]
# [[Adenovirus]]
# [[Parainfluenza]]
# [[Influenza]]
# [[Rhinovirus]]
 
=====Adults=====
 
* Typical Bacteria
# ''[[Streptococcus pneumoniae]]''
# ''[[Hemophilus influenzae]]''
# ''[[Escherichia coli]]''
# ''[[Klebsiella pneumoniae]]''
# ''[[Pseudomonas aeruginosa]]''
 
* Atypical Bacteria
# ''[[Mycoplasma pneumoniae]]''
# ''[[Chlamydophila pneumoniae]]''
# ''[[Legionella pneumophila]]''
 
* Viruses
# [[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.
 
* 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.


===Causes by Organ System===
===Causes by Organ System===
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|-bgcolor="LightSteelBlue"
|-bgcolor="LightSteelBlue"
| '''Iatrogenic'''
| '''Iatrogenic'''
|bgcolor="Beige"| General anaesthesia
|bgcolor="Beige"| No underlying cause
|-
|-
|-bgcolor="LightSteelBlue"
|-bgcolor="LightSteelBlue"
| '''Infectious Disease'''
| '''Infectious Disease'''
|bgcolor="Beige"| [[Acinetobacter baumann]], [[Acinetobacter spp]], [[Actinomycosis]], [[Adenovirus serotypes (1, 2, 3, 4, 5, 7, 14, 21, and 35]], [[Adenovirus]], [[Aids-related opportunistic infections]], [[Aspergillosis ]], [[Aspiration]], [[Bacillus anthracis]], [[Bird flu (avian influenza) ]], [[Blastomycosis]][[Burkholderia cepacia]], [[Burkholderia pseudomallei ]], [[C. pneumoniae]], [[Chicken pox]], [[Chlamydia pneumoniae ]], [[Chlamydophila pneumoniae]],[[Coccidioides immitis]], [[Coronaviruses]], [[Cryptococcus neoformans]], [[Cytomegalovirus]], [[Cytomegalovirus]], [[E.coli]], [[Enterovirus 71]] ,[[Enterovirus]], [[Francisella tularenis infection]], [[Gram-negative bacilli]], [[Group b streptococcal infections ]], [[H. influenzae]], [[H1n1 flu ]], [[Haemophilus influenzae]], [[Hantavirus ]], [[Herpes simplex virus]], [[Histoplasma capsulatum]], [[Histoplasmosis]], [[Human bocavirus]],[[Human parechovirus types 1, 2, and 3]], [[Influenza]], [[K.pneumonia]], [[Klebsiella sp]], [[Legionella pneumophila]], [Legionella species]], [[Legionnaires' disease]], [[Listeria monocytogenes]], [[M. pneumoniae]], [[Measles]], [[Melioidosis]], [[Metapneumovirus]], [[Middle east respiratory syndrome coronavirus]][[Moraxella catarrhalis]], [[Mumps]], [[Mycobacterium avium-intracellulare]], [[Mycobacterium haemophilum ]], [[Mycobacterium kansasii]], [[Mycoplasma pneumoniae]], [[Neisseria meningitidis]], [[New haven coronavirus]], [[Nocardia]], [[Paragonimiasis ]], [[Parainfluenza ]], [[Parainfluenza virus type 1 ]], [[Parainfluenza virus type 2]], [[Parainfluenza virus type 3 ]], [[Parainfluenza virus type 4 ..]], [[Parainfluenza]], [[Pittsburgh pneumonia]], [[Pneumococcal pneumonia ]], [[Pneumococcus]], [[Pneumocystis jiroveci]], [[Pneumonic plague ]], [[Proteus]], [[Pseudomonas aeruginosa]], [[Pseudomonas pseudomallei ]], [[Psittacosis ]], [[Psittacosis]], [[Q fever ]], [[Q fever]], [[Rat-bite fever]], [[Respiratory syncytial virus]], [[Respiratory viruses]], [[Rhinovirus]],[[Rhodococcus equi]], [[S. pneumoniae]], [[Sars .]], [[Sars]], [[Serratia ]], [[Severe acute respiratory syndrome]], [[Sporotrichosis ]][[Staphylococcus aureus]], [[Streptococcus agalactiae]], [[Streptococcus group a]], [[Streptococcus pneumoniae]], [[Swine flu]], [[Toxocariasis ]],[[Toxoplasma gondii]], [[Trichosporon ]], [[Trypanosomiasis ]], [[Type a influenza ]], [[Type a influenza subtype h1 ]], [[Type a influenza subtype h10n71]],[[Type a influenza subtype h1n1]], [[Type a influenza subtype h1n2 1]], [[Type a influenza subtype h2n2 ]], [[Type a influenza subtype h3n2]], [[Type a influenza subtype h5 ]], [[Type a influenza subtype h5n1 ]], [[Type a influenza subtype h7 ]], [[Type a influenza subtype h7n2 ]], [[Type a influenza subtype h7n3 ]],[[Type a influenza subtype h7n7 ]], [[Type a influenza subtype h9 ]], [[Type a influenza subtype h9n2]], [[Type b influenza ]], [[Type c influenza ]],[[Typhus]], [[Varicella-zoster virus]], [[Yersinia enterocolitica]], [[Yersinia pestis]], [[Zygomycosis]],
|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"
|-bgcolor="LightSteelBlue"
| '''Musculoskeletal/Orthopedic'''
| '''Musculoskeletal/Orthopedic'''
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{{col-break|width=33%}}
{{col-break|width=33%}}
* [[Acinetobacter baumannii]]
* [[Acinetobacter baumannii]]
* [[Acinetobacter]]


* [[Actinomycosis]]
* [[Actinomycosis]]
Line 342: Line 326:


* [[Gram-negative bacilli]]
* [[Gram-negative bacilli]]
* [[Haemophilus influenzae]]


* [[Influenza A virus subtype H1N1|H1N1 flu]]
* [[Influenza A virus subtype H1N1|H1N1 flu]]
Line 350: Line 332:


* [[Hantavirus]]
* [[Hantavirus]]
{{col-break|width=33%}}


* [[Herpes simplex virus]]
* [[Herpes simplex virus]]


* [[Histoplasma capsulatum]]
* [[Histoplasma capsulatum]]
{{col-break|width=33%}}


* [[Histoplasmosis]]
* [[Histoplasmosis]]
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* [[Metapneumovirus]]
* [[Metapneumovirus]]


* [[Middle east respiratory syndrome coronavirus]]
* [[Middle East respiratory syndrome coronavirus]]


* [[Moraxella catarrhalis]]
* [[Moraxella catarrhalis]]
Line 406: Line 388:


* [[Pneumocystis jiroveci]]
* [[Pneumocystis jiroveci]]
* [[Pneumonic plague]]


{{col-break|width=33%}}
{{col-break|width=33%}}
* [[Pneumonic plague]]


* [[Proteus]]
* [[Proteus]]
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* [[Pseudomonas aeruginosa]]
* [[Pseudomonas aeruginosa]]


* [[Psittacosis]]
* [[Chlamydophila psittaci|Chlamydophila psittaci (psittacosis)]]


* [[Rat-bite fever]]
* [[Rat-bite fever]]
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{{col-end}}
{{col-end}}


==References==
==References==
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[[Category:Disease]]
[[Category:Disease]]
[[Category:Pulmonology]]
[[Category:Pulmonology]]
[[Category:Infectious disease]]
[[Category:Pneumonia|Pneumonia]]
[[Category:Pneumonia|Pneumonia]]
[[Category:Emergency medicine]]
[[Category:Emergency medicine]]
[[Category:primary care]]

Latest revision as of 21:01, 29 July 2020

Pneumonia Main Page

Community-Acquired Pneumonia Microchapters

Home

Patient Information

Overview

Historical Perspective

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Pathophysiology

Causes

Differentiating Community-acquired pneumonia from other Diseases

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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)
  1. Streptococcus pneumoniae
  2. Mycoplasma pneumoniae
  3. Haemophilus influenzae
  4. Chlamydophila pneumoniae
  5. Influenza A and B, adenovirus, respiratory syncytial virus, parainfluenza
  1. Streptococcus pneumoniae
  2. Mycoplasma pneumoniae
  3. Haemophilus influenzae
  4. Legionella
  5. Aspiration
  6. Influenza A and B, adenovirus, respiratory syncytial virus, parainfluenza
  7. Yersinia enterocolitica
  1. Streptococcus pneumoniae
  2. Staphylococcus aureus
  3. Legionella
  4. Gram-negative bacilli
  5. Haemophilus influenzae
  6. Acinetobacter baumannii

Common Causes by Age Group
Age Group Neonates Children Adults
Bacteria
  1. Listeria monocytogenes
  2. Mycobacterium tuberculosis
  1. Mycoplasma pneumoniae
  2. Chlamydophila pneumoniae
  3. Legionella pneumophila
  4. Chlamydia trachomatis

Typical Bacteria

  1. Streptococcus pneumoniae
  2. Haemophilus influenzae
  3. Escherichia coli
  4. Klebsiella pneumoniae
  5. Pseudomonas aeruginosa

Atypical Bacteria

  1. Mycoplasma pneumoniae
  2. Chlamydophila pneumoniae
  3. Legionella pneumophila
Virus
  1. Herpes simplex virus
  2. Adenovirus
  3. Mumps
  4. Enterovirus
  1. Respiratory syncytial virus (RSV)
  2. Metapneumovirus
  3. Adenovirus
  4. Parainfluenza
  5. Influenza
  6. Rhinovirus
  1. Influenza
  2. Parainfluenza
  3. Respiratory syncytial virus (RSV)
  4. Metapneumovirus
  5. Adenovirus
  • 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

Children

Adults

The causes of CAP in adults are outlined in the following categories.

Viruses
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 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
Special Situations
Aspiration Pneumonia

Causes by Organ System

Cardiovascular No underlying causes
Chemical/Poisoning No underlying cause
Dental No underlying causes
Dermatologic No underlying causes
Drug Side Effect No underlying cause
Ear Nose Throat No underlying causes
Endocrine No underlying causes
Environmental No underlying cause
Gastroenterologic No underlying cause
Genetic No underlying cause
Hematologic No underlying causes
Iatrogenic No underlying cause
Infectious Disease Acinetobacter baumannii, Actinomycosis, Adenovirus (serotype 1, 2, 3, 4, 5, 7, 14, 21, 35), AIDS-related opportunistic infections, Aspergillosis, Aspiration, Bacillus anthracis, Bird flu (avian influenza), Blastomycosis, Burkholderia cepacia, Burkholderia pseudomallei, Chlamydophila pneumoniae, Chickenpox, Coccidioides immitis, Coronavirus, Coxiella burnetii (Q fever), Cryptococcus neoformans, Cytomegalovirus, Escherichia coli, Enterovirus, Francisella tularensis, Gram-negative bacilli, Haemophilus influenzae, H1N1 flu, Hantavirus, Herpes simplex virus, Histoplasma capsulatum, Histoplasmosis, Human bocavirus, Human parechovirus types 1, 2, and 3, Influenza, Klebsiella pneumoniae, Legionella micdadei, 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, New Haven coronavirus, Nocardia, Paragonimiasis, Parainfluenza, Pneumocystis jiroveci, Pneumonic plague, Proteus, Pseudomonas aeruginosa, Chlamydophila psittaci (psittacosis), Rat-bite fever, Respiratory syncytial virus (RSV), Rhinovirus, Rhodococcus equi, Streptococcus pneumoniae (pneumococcus), SARS, Serratia, Severe acute respiratory syndrome, Sporotrichosis , Staphylococcus aureus, Streptococcus agalactiae (group B streptococcus), Streptococcus pyogenes (group A streptococcus), Streptococcus pneumoniae, Swine flu, Toxocariasis , Toxoplasma gondii, Trichosporon , Trypanosomiasis, Typhus, Varicella-zoster virus, Yersinia enterocolitica, Yersinia pestis, Zygomycosis
Musculoskeletal/Orthopedic No underlying causes
Neurologic No underlying causes
Nutritional/Metabolic No underlying cause
Obstetric/Gynecologic No underlying causes
Oncologic No underlying cause
Ophthalmologic No underlying causes
Overdose/Toxicity No underlying cause
Psychiatric No underlying causes
Pulmonary No underlying causes
Renal/Electrolyte No underlying causes
Rheumatology/Immunology/Allergy No underlying cause
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Miscellaneous No underlying cause

Causes in Alphabetical Order


References

  1. ↑ 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)
  2. ↑ 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)
  3. ↑ 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)
  4. ↑ 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)
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