Systemic Mycoses Flashcards
what is the morphology of coccidioides and what is its life cycle like?
it is a thermally dimorphic mold and spherule. The mold grows in wet weather and releases infectious arthrospores when it dries. these are inhaled and change into spherules in the lung.
what is the most likely outcome of coccidioides?
60% have asymptomatic or flu like clearance by innate and cell mediated immunity
what is the moderate presentation of coccidioides?
valley fever/ desert rheumatism featuring pulmonary symptoms and erythema nodosum
what is the severe presentation of coccidioides?
major pneumonia or dissemination by hematogenous or macrophage dissemination
what are the risk factors for severe coccidioides infection?
old age, black/hispanic race, pregnancy, immunocompromise, and occupational high exposure
how is coccidioides diagnosed?
exam, history, PPD, biopsy for spherules, culture at different temps for dimorphism and serology for dissemination
when and how is coccidioides treated?
predisposition to complications (oral azoles), meningitis (fluconazole) and if pregnant or disseminated disease (amphotericin B)
where is coccidioides endemic to?
the US southwest
what is the morphology of histoplasma and where is it endemic to?
thermally dimorphic mold/yeast. endemic to ohio, missouri and mississippi river valleys
how is histoplasma infectious
the soil based infectious microconida can be kicked up by construction project and inhaled
what is the course of infection of histoplasma for previously healthy hosts?
it is usually cleared or contained in granulomas
what does a higher dose histoplasma infection look like?
it mimics TB
what is the course of histoplasma for a CMI deficient host?
it disseminates in macrophages as yeast survive lysosomal fusion by deactivating proteolytic enzymes
patients will have pancytopenia and ulcerations of their tongues
what should one look for when diagnosing histoplasma infection?
interaction with birds or bats, endemic area, immunocompromise or occupational exposure
how is histoplasma diagnosed?
biopsy for yeast in macrophages, culture for dimorphism and use ELISA for the antigen
how is histoplasma treated?
serious lung infection receives itraconazole. meningitis with fluconazole and disseminated infection with amphotericin B
what is the morphology of blastomyces? where is it endemic?
thermally dimorphic mold/yeast (mold has hyphae with pear shaped conidia). endemic to eastern US
what is the clinical course of most blastomyces infections?
innate immunity clears by destroying conidia or containing yeast with granulomas
what is the result of blastomyces infection in the immunosuppressed?
hematogenous spread
what are the presentations of moderate acute, moderate chronic and severe acute blastomyces infections?
MA; pneumonia with purulent sputum
MC: looks like TB
SA: ARDS
what cutaneous presentations may blastomycoses have?
erythema nodosum or ulcerating skin lesions
how is blastomycoses diagnosed?
speutum microscopy for yeast, culture for hyphae with pear shaped conidia, biopsy for yeast with supperating granulomas
how is blastomycoses treated?
itraconazole. fluconazole with meningitis and amphotericin B if severe
what is the morphology of paracoccidioides? where is it endemic?
thermally dymorphic mold with multibud yeast. endemic to rural Latin America
who gets severe paracoccidioides infections?
children and immunocompromised
what does the adult form of paracoccidioides infection look like?
it has a very long latency with skin and mucous membrane lesions
what is the juvenile presentation of paracoccidioides?
mucocutaneous lesions and more severe lymphadenopathy and hepatosplenomegaly
how is paracoccidioides diagnosed?
with pus or tissue KOH mount for yeast with multiple buds. culture mold form
how is paracoccidioides treated?
mild- itraconazole
severe- amphotericin B and support of the general health and immune system of the patient (semi-opportunistic infection)
