Pathophysiology of Invasive Mycoses Flashcards
how are systemic mycoses usually acquired
from inhalation of molds or spores in soil (noncontagious)
what patients do disseminated fungal infection occur in
compromised/suppressed imune systems
what fungus causes Histoplasmosis
dimorphic fungus that grows as mold in soil: Histoplasma Capsulatum
what fungal infection is associated with bird and bat droppings
histoplasmosis
where is most diseases of histoplasmosis and blastomycosis found
along OH and MS river valley
how does histoplasma capsulatum cause histoplasmosis
it is inhaled and germinates in the lungs and releases yeast that are engulfed by macrophages
what impairment causes yeast to continue to disseminate and not be contained
immunity impairment
manifestations of histoplasmosis
-can be asymptomatic
-pneumonia
-Disseminated (extrapulmonary) to the bone marrow
what fungus causes Blastomycosis
dimorphic fungus Blastomyces dematitidis that grows as mold in nature and yeast in the body
How is blastomycosis transmitted
nearly all infections acquired by inhalation of spores near recreational waters and woods
manifestations of blastomycosis
-can be asymptomatic
-pneumonia (mild)
-Disseminated (extrapulmonary) to the skin causing verrucous and ulcerative skin lesions
what is coccidioidomycosis and the fungus that causes it
Valley fever due to Coccidioides Immitis
what patient population is at most risk for coccidioidomycosis
patients in the SW U.S. that have high exposure to outdoor dust
how is coccidioidomycosis transmitted
spore inhalation (especially during dust storms)
manifestations of coccidioidomycosis
-can be asymptomatic
-pneumonia (mild)
what pathogen causes Cryptococcosis and where its found
Cryptococcus found in soil and pigeon droppings
manifestations of Cryptococcosis
-pneumonia
-CNS involvement causing meningitis, encephalitis, and mass lesions (cryptococcoma)
what is the most common cause of fungal sinusitis
aspergillus
what is the bacteria most responsible for causing aspergillosis
A. fumigatus
how is aspergillosis transmitted
inhalation of spores
manifestations of aspergillosis
-invasive pulmonary where fungal balls (aspergilloma) occur in patients with pre-existing pulmonary cavities
-allergic bronchopulmonary aspergillosis (ABPA) that is a hypersensitivity reaction in asthma or cystic fibrosis patients
-disseminated (extrapulmonary) spreading from lungs to the brain
what are the Candida funguses that cause candidiasis
C. albicans
C. glabrata
C. krusei
C. tropicalis
where does Candida colonize
commensal yeasts of the skin, vagina, and GI tract
how does Candida cause infection
acquired via GI tract, IV catheters, and invasion of mucocutaneous surfaces that suppresses microflora bacteria and contributes to overgrowth and ability to invade the bloodstream
manifestations of candidiasis
-cutaneous/mucocutaneous causing thrush (dense painless yeast growth in moist areas of body)
-hematogenous (invasive) candidiasis
-candiduria (cystitis following catheterization or therapy with broad spectrum antibacterial)
what is the source of hematogenous (invasive) candidiasis in healthy host
usual source of candidemia (blood infection) in IV lines
what is the source of hematogenous (invasive) candidiasis in neutropenic and other compromised patients
source is frequently the gut
