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{{Blastomycosis}}
{{Blastomycosis}}
{{CMG}}; {{AE}}; {{VB}}
{{CMG}}; {{AE}}; {{VB}}{{ADG}}
==Overview==
[[Blastomycosis]] is caused by a [[dimorphic fungi]] called [[Blastomyces dermatitidis]]. It has an average incubation period of 3 weeks to 3 months after exposure. The initial [[Inflamatory response|neutrophilic response]] and the subsequent [[Cell-mediated immune response|cell-mediated immune]] response are manifested as a [[suppurative]] [[tissue]] destruction seen in [[Lungs|lungs,]] [[skin]], and other [[organs]]. The [[histopathological]] hallmark findings on [[sputum]] microscopy is the multinucleated yeast form ([[budding]]).


==Pathophysiology==


==Overview==
===Transmission===
Blastomycosis is a [[dimorphic fungi]]. Infection occurs by inhalation of the fungus from its natural soil habitat. Once inhaled in the lungs, the conidia are mostly destroyed due to their susceptibility to neutrophils, leukocytes and macrophages. This explains the large number of asymptomatic infections from blastomycosis. Sometimes, a few conidia escape this protective mechanism and evolve into their yeast form, which being double walled structures are more resistant to destruction. This conversion releases a glycoprotien [[BAD-1]], which induces humoral and cellular immunity. This eventually manifests as a pyogranulomatous response which contains the infection at the site of entry. However, sometimes they multiply and get disseminate through the blood and lymphatics to other organs, including the skin, bone, genitourinary tract, and brain. The incubation period is about 30 to 100 days.  
*[[Inhalation]] of the [[conidia]] from its natural soil habitat is considered the most significant route of transmission.<ref name="pmid20375357">{{cite journal |vauthors=Saccente M, Woods GL |title=Clinical and laboratory update on blastomycosis |journal=Clin. Microbiol. Rev. |volume=23 |issue=2 |pages=367–81 |year=2010 |pmid=20375357 |pmc=2863359 |doi=10.1128/CMR.00056-09 |url=}}</ref>
*Other less common route of transmission is by [[Inoculation|cutaneous inoculation]] through direct [[skin]] [[injury]].<ref name="pmid23917880">{{cite journal |vauthors=Smith JA, Riddell J, Kauffman CA |title=Cutaneous manifestations of endemic mycoses |journal=Curr Infect Dis Rep |volume=15 |issue=5 |pages=440–9 |year=2013 |pmid=23917880 |doi=10.1007/s11908-013-0352-2 |url=}}</ref>
 
===Incubation===
*The [[incubation period]] varies from 3 weeks to 3 months after exposure.
===Pathogensis===
*Once inhaled in the [[lungs]], the [[conidia]] are mostly destroyed due to their susceptibility to [[neutrophils]], [[leukocytes]] and [[macrophages]]. <ref>{{cite book | last = Kauffman | first = Carol | title = Essentials of clinical mycology | publisher = Springer | location = New York | year = 2011 | isbn = 978-1-4419-6639-1 }}</ref>
*However, a few conidia escape this protective mechanism and evolve into [[Yeast|yeast form]], which being double walled structures are more resistant to destruction.  
*This conversion releases a [[Glycoprotein|glycoprotien]] BAD-1, which induces [[cell mediated immunity]]. <ref name="pmid18070904">{{cite journal |vauthors=Koneti A, Linke MJ, Brummer E, Stevens DA |title=Evasion of innate immune responses: evidence for mannose binding lectin inhibition of tumor necrosis factor alpha production by macrophages in response to Blastomyces dermatitidis |journal=Infect. Immun. |volume=76 |issue=3 |pages=994–1002 |year=2008 |pmid=18070904 |pmc=2258846 |doi=10.1128/IAI.01185-07 |url=}}</ref>
*This results in a pyogranulomatous response at the primary site of [[infection]] ([[lungs]]).
*Which eventually leads to the formation of a [[Granulomas|non-caseating granulomas]].
[[Image:Blastomycosis-lifecycle.jpg|center|frame|Blastomycosis - life cycle and epidemiology - Source: https://www.cdc.gov/]]
 
===Dissemination===
*The [[fungi]] can disseminate through the [[blood]] and [[lymphatics]] to other organs, such as [[skin]], [[bone]], [[genitourinary tract]] and [[CNS|brain]].<ref name="pmid20375357">{{cite journal |vauthors=Saccente M, Woods GL |title=Clinical and laboratory update on blastomycosis |journal=Clin. Microbiol. Rev. |volume=23 |issue=2 |pages=367–81 |year=2010 |pmid=20375357 |pmc=2863359 |doi=10.1128/CMR.00056-09 |url=}}</ref>
 
===Immune response===
*Cyotoxic [[T cells]] are mainly responsible for persistence of [[infection]] and [[tissue]] damage.
*Ineffective [[Hypersensitivity|type 4 delayed hypersensitivity]] reaction containing [[macrophages]] and [[T cells|sensitized T cells]] are mainly responsible for the [[cutaneous]] manifestations. <ref name="pmid18070904">{{cite journal |vauthors=Koneti A, Linke MJ, Brummer E, Stevens DA |title=Evasion of innate immune responses: evidence for mannose binding lectin inhibition of tumor necrosis factor alpha production by macrophages in response to Blastomyces dermatitidis |journal=Infect. Immun. |volume=76 |issue=3 |pages=994–1002 |year=2008 |pmid=18070904 |pmc=2258846 |doi=10.1128/IAI.01185-07 |url=}}</ref>
===Genetics===
There is no known genetic association for blastomycosis.
===Microscopic Pathology===
Classic appearance on modified Wright's stain <ref name="pmid20375357">{{cite journal |vauthors=Saccente M, Woods GL |title=Clinical and laboratory update on blastomycosis |journal=Clin. Microbiol. Rev. |volume=23 |issue=2 |pages=367–81 |year=2010 |pmid=20375357 |pmc=2863359 |doi=10.1128/CMR.00056-09 |url=}}</ref>
*[[Multinucleated]] [[Yeast|yeas]]<nowiki/>t [[cell]]
*Single broad-based bud
*Round to oval in shape with 12 um diameter
[[Image:Blastomycosis.JPG|center|500x500px]]


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}


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Latest revision as of 20:37, 29 July 2020

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: ; Vidit Bhargava, M.B.B.S [2]Aditya Ganti M.B.B.S. [3]

Overview

Blastomycosis is caused by a dimorphic fungi called Blastomyces dermatitidis. It has an average incubation period of 3 weeks to 3 months after exposure. The initial neutrophilic response and the subsequent cell-mediated immune response are manifested as a suppurative tissue destruction seen in lungs, skin, and other organs. The histopathological hallmark findings on sputum microscopy is the multinucleated yeast form (budding).

Pathophysiology

Transmission

Incubation

Pathogensis

Blastomycosis - life cycle and epidemiology - Source: https://www.cdc.gov/

Dissemination

Immune response

Genetics

There is no known genetic association for blastomycosis.

Microscopic Pathology

Classic appearance on modified Wright's stain [1]

References

  1. 1.0 1.1 1.2 Saccente M, Woods GL (2010). "Clinical and laboratory update on blastomycosis". Clin. Microbiol. Rev. 23 (2): 367–81. doi:10.1128/CMR.00056-09. PMC 2863359. PMID 20375357.
  2. Smith JA, Riddell J, Kauffman CA (2013). "Cutaneous manifestations of endemic mycoses". Curr Infect Dis Rep. 15 (5): 440–9. doi:10.1007/s11908-013-0352-2. PMID 23917880.
  3. Kauffman, Carol (2011). Essentials of clinical mycology. New York: Springer. ISBN 978-1-4419-6639-1.
  4. 4.0 4.1 Koneti A, Linke MJ, Brummer E, Stevens DA (2008). "Evasion of innate immune responses: evidence for mannose binding lectin inhibition of tumor necrosis factor alpha production by macrophages in response to Blastomyces dermatitidis". Infect. Immun. 76 (3): 994–1002. doi:10.1128/IAI.01185-07. PMC 2258846. PMID 18070904.

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