A 40 year old farmer presents with chronic cough, fever, anorexia. O/E lymphadenopathy and hepatosplenomegaly present. Chest X-ray shows infiltrates, patchy opacities. Aspiration of lymph node shows intracellular yeasts. Culture grows thick walled spherical spores with tuberculate microconidia. Diagnosis
High-Yield Explanation
Answer: c) Histoplasmosis (JAWETZ 27th EDITION P-679)HISTOPLASMOSIS (DARLING DISEASE)* H. capsulatum - Non capsulated intracellular fungi which infects RES* Classical histoplasmosis - caused by H.capsulatum var capsulatum - mostly involves lungs* African histoplasmosis - caused by H.capsulatum var duboisii - mostly involves skin, subcutaneous tissues and bones* Infection acquired by inhalation of microconidia* Majority of infection are asymptomatic, heal and leaves an area of miliary calcification* Disseminated disease resembling TB seen in AIDS, patients on prednisone, methotrexate, anti TNF-a agents* Granulomatous and ulcerative lesions can develop in skin and mucosa* Progressive disseminated histoplasmosis (PDH) can involve multiple organs, most commonly the bone marrow, spleen, liver, adrenal glands, and mucocutaneous membranes* Stains for Histoplasma> Lactophenol cotton blue stain - conidia> Grocott's methenamine silver stain - budding yeast> Hematoxylin and eosin stain - intracellular yeast* In tissues - yeast forms occur within phagocytes as oval budding cells* Fungal culture is the gold standard for diagnosis* Sabouraud's agar - white cottony mycelial growth with tuberculate spores or finger like projections* Treatment - Amphotericin B