Microbiology - Pulmonary fungal infections I (Dimorphs)/II (Opportunitic Infections) - Greenblatt Flashcards
How is histoplasma treated?
Treat serious lung w/ itraconazole, meningitis w/ fluconazole, disseminated w/ Amphotericin B
What are the important diagnostic factors in the diagnosis of histoplasma?
look for pancytopenia and ulcerations on tongue. Also for diagnosis: history (birds, bats, endemic area, immunocompromised, occupation), biopsy for yeast in macrophages, cultures for dimorphism, ELISA for antigen.
What are the manifestations of histoplasma infections?
causes pulmonary symptoms, previously-healthy usually clear or contain in granulomas, higher-dose infection produces TB mimic, CMI-deficient host disseminates in macrophages (yeast survive lysosomal fusion)
What kind of organism is histoplasma?
thermally dimorphic (mold/yeast), endemic to Ohio, Missouri, and Mississippi river valleys, soil-based, infectious microconidia can be kicked up by construction projects
What kind of organism is coccidiodes?
thermally dimorphic (mold/spherule), endemic to US Southwest, mold grows in wet weather, releases infectious arthrospores in dry, spores inhaled, change form
How is coccidiodes treated?
Treat if predisposed to complications (oral azoles), meningitis (fluconazole), pregnant or disseminated (Amphotericin B)
How is coccidiodes diagnosed?
Diagnose by exam, history, PPD, biopsy for spherules, culture for dimorphism, serology for dissemination
What are the risk factors for coccidiodes infection?
Risk factors: age, race, pregnancy, immunocompromise, occupational high exposure
What are the symptoms of severe coccidiodes?
severe: major pneumonia or dissemination (either bare or in macrophages)
How do most coccidiodes infections clear?
60% Mild: asymptomatic or flulike clearance by innate or containment by CMI,
moderate: valley fever/ desert rheumatism: pulmonary+EN,
What kind of organism is blastomyces?
thermally dimorphic (mold/yeast), endemic to Eastern US.
How do most cases of blastomyces resolve?
Innate immunity clears most cases, destroys conidia easily, yeasts are harder to kill (BAD1),
graulomatous response contains most, immunosuppression predisposes to hematogenous spread.
Moderate acute: pneumonia w/ purulent sputum,
Moderate chronic: mimics TB, Severe acute: ARDS.
May include EN or ulcerating skin lesions.
How is blastomyces diagnosed?
Diagnose by sputum microscopy for yeast, culture for hyphae w/ pear-shaped conidia, biopsy for yeast w/ supperating (not caseating) granulomas.
How is blastomyces infection treated?
Treat w/ itraconazole, fluconazole if meningitis, Amphotericin B if severe.
What kind of organism is paracoccidiodes?
thermally dimorphic (mold/multibud yeast), endemic to rural Latin America