Systemic Mycoses Flashcards

1
Q

what is the morphology of coccidioides and what is its life cycle like?

A

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.

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2
Q

what is the most likely outcome of coccidioides?

A

60% have asymptomatic or flu like clearance by innate and cell mediated immunity

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3
Q

what is the moderate presentation of coccidioides?

A

valley fever/ desert rheumatism featuring pulmonary symptoms and erythema nodosum

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4
Q

what is the severe presentation of coccidioides?

A

major pneumonia or dissemination by hematogenous or macrophage dissemination

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5
Q

what are the risk factors for severe coccidioides infection?

A

old age, black/hispanic race, pregnancy, immunocompromise, and occupational high exposure

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6
Q

how is coccidioides diagnosed?

A

exam, history, PPD, biopsy for spherules, culture at different temps for dimorphism and serology for dissemination

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7
Q

when and how is coccidioides treated?

A

predisposition to complications (oral azoles), meningitis (fluconazole) and if pregnant or disseminated disease (amphotericin B)

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8
Q

where is coccidioides endemic to?

A

the US southwest

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9
Q

what is the morphology of histoplasma and where is it endemic to?

A

thermally dimorphic mold/yeast. endemic to ohio, missouri and mississippi river valleys

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10
Q

how is histoplasma infectious

A

the soil based infectious microconida can be kicked up by construction project and inhaled

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11
Q

what is the course of infection of histoplasma for previously healthy hosts?

A

it is usually cleared or contained in granulomas

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12
Q

what does a higher dose histoplasma infection look like?

A

it mimics TB

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13
Q

what is the course of histoplasma for a CMI deficient host?

A

it disseminates in macrophages as yeast survive lysosomal fusion by deactivating proteolytic enzymes
patients will have pancytopenia and ulcerations of their tongues

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14
Q

what should one look for when diagnosing histoplasma infection?

A

interaction with birds or bats, endemic area, immunocompromise or occupational exposure

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15
Q

how is histoplasma diagnosed?

A

biopsy for yeast in macrophages, culture for dimorphism and use ELISA for the antigen

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16
Q

how is histoplasma treated?

A

serious lung infection receives itraconazole. meningitis with fluconazole and disseminated infection with amphotericin B

17
Q

what is the morphology of blastomyces? where is it endemic?

A

thermally dimorphic mold/yeast (mold has hyphae with pear shaped conidia). endemic to eastern US

18
Q

what is the clinical course of most blastomyces infections?

A

innate immunity clears by destroying conidia or containing yeast with granulomas

19
Q

what is the result of blastomyces infection in the immunosuppressed?

A

hematogenous spread

20
Q

what are the presentations of moderate acute, moderate chronic and severe acute blastomyces infections?

A

MA; pneumonia with purulent sputum
MC: looks like TB
SA: ARDS

21
Q

what cutaneous presentations may blastomycoses have?

A

erythema nodosum or ulcerating skin lesions

22
Q

how is blastomycoses diagnosed?

A

speutum microscopy for yeast, culture for hyphae with pear shaped conidia, biopsy for yeast with supperating granulomas

23
Q

how is blastomycoses treated?

A

itraconazole. fluconazole with meningitis and amphotericin B if severe

24
Q

what is the morphology of paracoccidioides? where is it endemic?

A

thermally dymorphic mold with multibud yeast. endemic to rural Latin America

25
Q

who gets severe paracoccidioides infections?

A

children and immunocompromised

26
Q

what does the adult form of paracoccidioides infection look like?

A

it has a very long latency with skin and mucous membrane lesions

27
Q

what is the juvenile presentation of paracoccidioides?

A

mucocutaneous lesions and more severe lymphadenopathy and hepatosplenomegaly

28
Q

how is paracoccidioides diagnosed?

A

with pus or tissue KOH mount for yeast with multiple buds. culture mold form

29
Q

how is paracoccidioides treated?

A

mild- itraconazole

severe- amphotericin B and support of the general health and immune system of the patient (semi-opportunistic infection)