Fungal Pneumonia Flashcards
endemic fungal pneumonia
histoplasmosis
blastomycosis
coccidioidomycosis
fungal pneumonia associated with immunosuppression
aspergillosis
pneumocystosis
What are some of the major characteristics of endemic mycoses?
thermally dimorphic fungi that exist in nature, soil
hyphal form in the environment, yeast form in tissue
inhalation leads to pulmonary infection and dissemination
no evidence of transmission among humans or animals
otherwise healthy individuals are infected
general characteristics of Histoplasma capsulatum
soil-based fungus associated with river valleyes and bird and bat guano
in the US, mostly endemic to Ohio and Mississippi river valleys
acquisition associated with disruption of the soil by excavation or construction, inhilation and pulmonary infection
dimorphic - mycelial (37 degrees C or higher) and yeast phase
hallmark of tissure response is caseating or noncaseating granulomas
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clinical manifestations of H. capsulatum
> 90% go unrecognized, asymptomatic or mild influenza-like illness
Ghon complex and pulmonary calcifications are common in healed pulmonary histoplasmosis
complications of H. capsulatum infection
mediastinal lymphadenitis
mediastinal fibrosis
cavitary pulmonary histoplasmosis
progressive disseminated histoplasmosis (PDH)
diagnosis of Histoplasmosis
culture in brain heart infusion agar with blood, antibiotics, and cyclohexamide
cultures incubated for 30 degrees C for up to 6 weeks
majority cultures show grwoth within 7 days
sputum culture
histopathology
rapid diagnosis by polysaccharide antigen detection in urin, serum, BAL fluid
histopathology of Histoplasmosis
yeast visualized poorly by H and E stain
better seen with periodic acid-Schiff (PAS) and Gomorimethenamine silver (GMS) stains
treatnebt if Histoplasmosis
acute pulmonary disease
if symptoms less than 4 weeks no treatment
if symptoms greater than 4 weeks itraconazole for 6-12 weeks
chronic pulmonary disease, disseminated disease, granulomatous mediastinitis - Amphotericin B then Itraconazole for 6-24 months
general characteristics of Blastomyces dermatitidis
organism found in warm, moist soil of wooded areas rich in organic debris, such as decaying vegetation
dimorphic funcgus, mycelial form at room temeprature and yeast form at 37 degrees C
endemic to North America, including southeasterna nd south central states, especially those bordering the Mississippi and Ohio River basins and the Great Lakes
usualt portal of entry in humans is through the inhalation of conidia, which convert to the yeast phase in the lung
the typical inflammatory response consists of clusters of neutrophils and noncaseating granulomas with epithelioid and giant cells
Broad Based Budding yeast
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clinical manifestation of Blastomycosis
pulmonary blastomycosis - acute or chronic, mimics infection with pyogenic bacteria, TB, other fungal infections, and malignancy
extrapulmonary manifestations - cutaneous disease and bone infection
diagnosis of Blastomycosis
definitive diagnosis requires recovery in culture
can also examine secretions
histopathological examination - pyogranuloma, GMS stain
antigen assay
serologic testing - complement fixation, immunodiffusion, radioimmunoassay, ezyme immunoassay
treatment of Blastomycosis
asymptomatic disease limited to the lungs - follow the patient closely for disease progression or dissemination
in immunocompromized, progressive pulmonary disease, or extrapulmonary disease - amphotericin B and itraconazole
What are the two species of Coccidioides?
- Coccidioides immitis* (CA)
- Coccidioides Posadasii* (other states and countries outside the US)
Where is Coccidioidomycosis endemic to?
southwestern US, especially in New Mexico, Arizona, and the San Joaquin Valley of California
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