Endemic (Systemic) Mycoses Flashcards
Endemic mycoses characteristics
All dimorphic, exist in soil as molds, develop following inhalation of various fungi. No defect in immunity required to become infected, most infections asymptomatic. Based on geographic distribution.
Where is histoplasmosa capsulatum found?
Found in Ohio and Mississippi River Valleys.
Physical findings of histoplasmosis
Less than 5 percent of primary infections are symptomatic. Mimics TB. Granuloma in lung, acute pericarditis in up to 5 percent of cases. Regional lymph node enlargement. Healing lesions with calcifications, can be re-activated with immunosuppression years later.
Chronic pulmonary histoplasmosis
Involving upper lobes, associated with COPD.
Progressive disseminated histoplasmosis
Associated with HIV, steroid therapy, very young or old. Most acute occurs early after primary infection, presents with fever, weight loss and diffuse lung infiltrates, sometimes hepatosplenomegaly and pancytopenia. Fatal within weeks if untreated. Treat with amphotericin..
Lab characteristics and treatment of histoplasmosis
Use a urine antigen test to diagnose disseminated disease. Histology: thin isthmus between yeast and bud.
Most pulmonary infections self-limited, if severe treat with oral itraconazole.
Geography of blastomycosis
Pine forests and river basis in midwestern US
Blastomycosis manifestations
Skin disease, maculopapular lesions that become pustular and crusting. Skin abscesses may be mistaken for squamous cell carcinomas. Bone and joint involvement in 10-15 percent of cases.
Blastomyces dermatitidis lab characteristics
Direct exam: KOH mount of sputum or aspiration yields thick-walled, broad-based budding yeasts.
Histo: thick isthmus (compared to histoplasmosis with thin isthmus)
Blastomycosis treatment
IV Amphotericin B. If cutaneous or localized pulmonary disease, give oral itraconazole.
Geography of coccidioidomycsis
Southwestern United States
Symptoms of coccidioidomycosis
Moderate to severe symptoms of respiratory infection. Usually clear with symptomatic treatment, but thin-walled eggshell cavities may persist.
Worst complication: Coccidiodal meningitis
Lab characteristics of coccidioidomycosis
Direct exam: spherules
Histo: Methenamine silver, PAS and HE all show organism.
Culture: Arthroconidia highly infectious, so BE CAREFUL.
Serology: IMPORTANT. Complement fixation and immunodiffusion tests extremely useful, excellent correlation with active disease.
Treatment of coccidioidomycosis
Azole antifungals itraconazole and fluconazole. Severe: Amphotericin
Relapses of infection are common.
Geography of paracoccidioidomycosis
Central and South America
