Fungal infections of the respiratory tract Flashcards
what are the pulmonary fungal infections?
histoplasmosis
coccidioidmycosis
blastomycosis
pneumocystis
what is the most common endemic fungal infection in the US?
histoplasmosis
what are risk factors for histoplasmosis?
bird / bat exposure
building demolition
cave exploring
how does histoplasmosis infection occur?
inhalation of mycelia or conidia
where do the histoplasmosis microconidia survive in the host? what occurs then?
alveolar macrophage
converts to yeast form for hematogenous spread
what are the two avenues of histoplasmosis infection?
- cell mediated immunity controls infection, leaves calcified nodules in lung, spleen
- dissemination leading to infection occurs in large inocula, immunocompromised
what are the symptoms of histoplasmosis?
fever chills cough chest pain myalgias headache
what does histoplasmosis show on PE?
rales
possible consolidation
what does imaging show for histoplasmosis?
hilar and mediastinal lymphadenopathy with focal infiltrates which are patchy or nodular in appearance
nodes may become calcified
histoplasmosis needs to be differentiated from what other condition?
sarcoidosis
what are the clinical syndromes associated with histoplasmosis?
acute diffuse pulmonary histoplasmosis (extensive exposure)
chronic pulmonary histoplasmosis (underlying COPD)
what is seen with acute diffuse pulmonary histoplasmosis (extensive exposure)?
reticulonodular or miliary infiltrates
possible respiratory failure
what is seen with chronic pulmonary histoplasmosis (underlying COPD)?
fever, chills, chest pain, productive cough
may have apical infiltrates with cavitation
what should be considered in a fungal disease with erythema nodosum / multiforme?
histoplasmosis
what is present on histopathology for histoplasmosis?
granulomas on biopsy yeast forms (special stain)
what is the most useful diagnostic test for histoplasmosis? what types of specimen?
culture (blood, urine, BAL fluid)
what are the medications for histoplasmosis?
amphotericin B
itraconazole
fluconazole
posaconale / voriconazole
what are the endemic areas for coccidioidomycosis?
california, arizona, southern nevada
what is the pathogenesis of coccidioidomycosis?
- inhalation of a single arthroconidium
2. in the lung the barrel shaped arthroconidium changes to a spherical structure which ruptures to release endospores
what is the most common diagnostic test for coccidioidomycosis?
serological testing
what is the treatment for coccidioidomycosis - chronic fibrocavitary?
12 months of an azole
what is the pathogenesis of blastomycosis?
systemic pyorgranulomatous infection due to inhalation of mycelial conidia of blastomyces dermatiditis
what is a major risk factor for pneumocystis?
immunosuppression
how does pneumocystis present in non-HIV patients? what are the CT findings?
fulminant respiratory failure with progression of bilateral infiltrates after 1-2 days
ground glass changes
what is the best treatment for pneumocystis in non-HIV patients?
TMP-SMX
