Pneumocystis pneumonia: Difference between revisions

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'''For patient information click [[{{PAGENAME}} (patient information)|here]]'''
#Redirect[[Pneumocystis jirovecii pneumonia]]
{{DiseaseDisorder infobox |
  Name          = Pneumocystis jirovecii pneumonia |
  ICD10          = {{ICD10|B|20|6|b|20}} |
  ICD9          = {{ICD9|136.3}} |
  ICDO          = |
  Image          = Pneumocystis.jpg |
  Caption        = '''''Pneumocystis jirovecii''''' cysts from bronchoalveolar lavage, stained with [[Toluidin blue O stain]] |
  OMIM          = |
  OMIM_mult      = |
  MedlinePlus    = 000671 |
  eMedicineSubj  = |
  eMedicineTopic = |
  DiseasesDB    = 10160 |
  MeshID        = D011020 |
}}
{{Search infobox}}
{{CMG}}
 
==Overview==
'''''Pneumocystis'' pneumonia''' ('''PCP''') is a form of [[pneumonia]] caused by the yeast-like [[fungus|fungal]] ''Pneumocystis jirovecii'' (Jirovecii is pronounced "yee row vet zee eye"). The causal agent was originally described as a protozoan and spelled ''P. jiroveci'' and prior to then was classified as a form of ''Pneumocystis carinii'', a name still in common usage.<ref name=Stringer_2002>{{cite journal | author=Stringer JR, Beard CB, Miller RF, Wakefield AE | title=A new name (''Pneumocystis jiroveci'') for ''Pneumocystis'' from humans | journal=Emerg Infect Dis | year=2002 | pages=891-6 | volume=8 | issue=9 | id=PMID 12194762}}</ref><ref name=Redhead_2006>{{cite journal | author=Redhead SA, Cushion MT, Frenkel JK, Stringer JR | title=''Pneumocystis'' and ''Trypanosoma cruzi'': nomenclature and typifications | journal=J Eukaryot Microbiol | year=2006 | pages=2–11 | volume=53 | issue=1 | id=PMID 16441572}}</ref> These names are discussed below. As a result, '''Pneumocystis pneumonia (PCP)''' has also been known as '''Pneumocystis jiroveci[i] pneumonia''' and as '''Pneumocystis carinii pneumonia''', as is also explained below.<ref  name=Cushion_1998>{{cite journal | author=Cushion MT .| title =  Chapter 34. ''Pneumocystis carinii''. In: Collier, L., Balows, A. & Sussman, M. (ed.), Topley and Wilson's Microbiology and Microbial Infections 9th ed.  Arnold and Oxford Press, New York. | year = 1998 | pages = 645–683}}</ref><ref  name=Cushion_1998b>{{cite journal | author=Cushion MT | title =  Taxonomy, genetic organization, and life cycle of ''Pneumocystis carinii'' | | journal = Semin. Respir. Infect | year = 1998 | volume = 13 | issue =4 | pages = 304–312}}</ref><ref  name=Cushion_2004>{{cite journal | author=Cushion MT | title =  ''Pneumocystis'': unraveling the cloak of obscurity | | journal = Trends Microbiol | year = 2004 | volume = 12 | issue =5 | pages = 243–249}}</ref>
 
It is relatively rare in people with normal immune systems but common among people with
weakened [[immune system]]s, such as premature or severely malnourished children, the elderly, and especially [[AIDS]] patients, in whom it is most commonly observed today.<ref name=Sherris>{{cite book | author = Ryan KJ; Ray CG (editors) | title = Sherris Medical Microbiology | edition = 4th ed. | publisher = McGraw Hill | year = 2004 | id = ISBN 0838585299 }}</ref> PCP can also develop in patients who are taking [[Immunosuppressive drug|immunosuppressant medications]] (e.g. patients who have undergone [[Organ transplant|solid organ transplantation]]) and in patients who have undergone [[bone marrow transplantation]].
 
The organism is distributed worldwide<ref name=Morris_2004>{{cite journal | author=Morris A et al | title= Current Epidemiology of Pneumocystis Pneumonia | journal=Emerg Infect Dis | year=2004 | pages=1713-1720 | volume=10 | issue=10 | id=PMID 15504255}}</ref>[http://www.cdc.gov/ncidod/eid/vol10no10/03-0985.htm].
 
==Epidemiology==
Pneumocystis pneumonia has been described in all continents except Antarctica.<ref name=Morris_2004/>  It was originally described as a rare cause of [[pneumonia]] in [[neonate]]s.  It is believed to be an environmental organism, and human-to-human transmission is thought not to occur (although in one outbreak of 12 cases among transplant patients in Leiden it was postulated, but not proven, that human-to-human spread may have occurred).<ref>{{cite journal | author=de Boer M, Bruijnesteijn van Coppenraet L, Gaasbeek A, ''et al.'' | title=An outbreak of Pneumocystis jiroveci pneumonia with 1 predominant [[genotype]]
among renal transplant recipients: interhuman transmission or a common environmental source? | journal=Clin Infect Dis |year=2007 | volume=44 | issue=9 | pages=1143&ndash;49 | id=PMID 17407029 }}</ref>  Greater than 75% of children are seropositive by the age of 4, which suggest a high background exposure to the organism.
 
Since the start of the [[HIV]] pandemic, PCP has been closely associated with AIDS. Because it only occurs in an immunocompromised host, it may be the first clue to a new AIDS diagnosis if the patient has no other reason to be immunocompromised (e.g. taking immunosuppressive drugs for [[organ transplant]]). An unusual rise in the number of PCP cases in North America, noticed when physicians began requesting large quantities of the rarely used antibiotic [[pentamidine]], was the first clue to the existence of AIDS in the early 1980s.<ref>{{cite journal | title=A Cluster of Kaposi's Sarcoma and ''Pneumocystis carinii'' pneumonia among homosexual male residents of Los Angeles and Range Counties, California | author=Fannin S, Gottlieb MS, Weisman JD, ''et al.'' | year=1982 | journal=MMWR Weekly | volume=31 | issue=32 | pages=305&ndash;7 }}</ref><ref>{{cite journal | author=Masur H, Michelis MA, Greene JB, ''et al.'' |title=An outbreak of community-acquired Pneumocystis carinii pneumonia |journal=N Engl J Med |year=1981 |volume=305 |pages=1431–8 | url=http://www.cdc.gov/mmwr/preview/mmwrhtml/00001114.htm }}</ref>
 
Prior to the development of more effective treatments, PCP was a common and rapid cause of death in persons living with AIDS. Much of the incidence of PCP has been reduced by instituting a standard practice of using oral [[co-trimoxazole]] to prevent the disease in people with [[CD4]] counts less than 200/mm³. In populations that do not have access to preventative treatment, PCP continues to be a major cause of death in AIDS.
 
In [[immunocompromised]] patients (e.g. cancer patients on [[chemotherapy]], or persons living with [[AIDS]] with a [[T helper cell|CD4+ T-cell]] count below 200/μl), [[prophylaxis]] with regular [[pentamidine]] inhalations or [[sulfamethoxazole]]/[[trimethoprim]] ([[co-trimoxazole]] or [[TMP-SMX]]) may be necessary to prevent PCP.
 
==Symptoms==
Symptoms of PCP include fever, non-productive cough, shortness of breath (especially on exertion), weight loss and night sweats. There is usually not a large amount of [[sputum]] with PCP unless the patient has an additional bacterial infection. The fungus can invade other visceral organs, such as the [[liver]], [[spleen]] and [[kidney]], but only in a minority of cases.
 
==Pathophysiology==
 
==Diagnosis==
The diagnosis can be confirmed by the characteristic appearance of the [[chest x-ray]] which shows widespread pulmonary infiltrates, and an [[arterial blood gas|arterial oxygen level]] (pO<sub>2</sub>) strikingly lower than would be expected from symptoms. The diagnosis can be definitively confirmed by pathologic identification of the causative organism in induced [[sputum]] or [[bronchia]]l washings obtained by [[bronchoscopy]] with coloration by [[toluidine blue]] or [[immunofluorescence assay]], which will show characteristic [[cyst]]s [http://www.bmb.leeds.ac.uk/mbiology/ug/ugteach/icu8/std/pcp.html].
 
''Pneumocystis'' infection can also be diagnosed by [[immunofluorescent]] or [[histochemical staining]] of the specimen, and more recently by molecular analysis of [[PCR]] products comparing [[DNA]] samples. Notably, simple molecular detection of ''Pneumocystis jirovecii'' in lung fluids does not mean that a person has Pneumocystis pneumonia or infection by [[HIV]]. The fungus appears to be present in healthy individuals also in the general population.<ref name=Medrano_2005>{{cite journal | author=Medrano FJ et al | title= ''Pneumocystis jiroveci''i in General Population | journal=Emerg Infect Dis | year=2005 | pages=245–250 | volume=11 | issue=2 | id=PMID 15752442 }}</ref>
 
[[Image:PCPxray.jpg|thumb|left|250px|'''X-ray of Pneumocystis jirovecii pneumonia''' There is increased white (opacity) in the lower lungs on both sides, characteristic of ''Pneumocystis'' pneumonia]]
 
==Life-cycle==
 
==Treatment==
 
==Guidelines==
To read about guidelines for prevention and treatment of Pneumocystis pneumonia Infections in HIV-Infected Adults and Adolescents, click [[HIV opportunistic infection pneumocystis pneumonia: prevention and treatment guidelines|'''here''']].
 
==References==
{{Reflist|2}}
 
{{Mycoses}}
[[de:Pneumocystis jiroveci]]
[[es:Pneumocystis jiroveci]]
[[fr:Pneumocystose]]
[[fr:Pneumocystis jiroveci]]
[[ja:ニューモシスチス肺炎]]
[[pt:Pneumocistose]]
[[pl:Pneumocystis jiroveci]]
 
[[Category:Fungal diseases]]
[[Category:Ascomycota]]
[[Category:Infectious disease]]
[[Category:Overview complete]]
 
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Latest revision as of 19:00, 27 September 2012