Snapshot A 38-year-old man presents to an urgent care clinic in Ohio for a 3-week cough. He reports having fevers, chills, and fatigue. He recently went on a local hiking trip that included waterfalls, freshwater lakes, and caves. He reports his cough was worse in the beginning but has lingered. He denies any rashes, vomiting, or diarrhea. A chest radiograph shows patchy pulmonary infiltrates and hilar lymphadenopathy. A sputum sample under microscopy shows macrophages with intracellular yeast cells. (Histoplasmosis) Introduction Introduction dimorphic yeasts mold form in the soil, outside the body grows on Sabouraud agar yeast form in tissues, inside the body grows on blood agar Coccidioides immitis is an exception spherule form, not yeast, in tissue clinical syndromes pneumonia chronic inflammatory lung disease systemic dissemination Overview of Systemic Mycoses Clinical Syndrome Histoplasmosis Coccidioidomycosis Blastomycosis Paracoccidioidomycosis Organism Histoplasma capsulatum Coccidioides immitis Coccidioides posadasii Blastomyces dermatitidis Paracoccidioides brasiliensis Paracoccidioides lutzii Demographics Mississippi Ohio River Valley Southwestern US California Eastern US Central US Latin America Skin manifestations Ulcers on oral mucosa Erythema nodosum Erythema multiforme Verrucous skin lesions Verrucous skin lesions Histology Macrophages filled with fungus cells Spherules (larger than red blood cells (RBCs)) filled with endospores Broad-based budding yeast (same size as RBCs) Budding yeast larger than RBCs Differential tuberculosis also affects the pulmonary system causes granulomas, cavitations, and calcifications unlike these systemic mycoses, tuberculosis can be transmitted person to person Treatment amphotericin B systemic infections itraconazole or fluconazole localized infections EPIDEMIOLOGY demographics depends on geographic location transmission inhalation of spores cannot be transmitted between people ETIOLOGY pathogenesis inhalation causes a pulmonary infection fungi can then disseminate to other organs, particularly the skin causes granulomas composed of epithelioid cells and multinucleated giant cells Th1 mediated Histoplasmosis Histoplasma capsulatum demographics Mississippi Ohio River Valley (Ohio and Tennessee) risk factors bird or bat excretions chicken farms exploring caves or spelunking HIV infection Presentation pneumonia usually self-limiting chronic cavitary lung disease hilar lymphadenopathy gastrointestinal symptoms splenomegaly oral mucosal ulcers on tongue or palate Imaging chest radiograph normal or with patchy infiltrates with hilar/mediastinal lymphadenopathy Studies detection of antigen in serum or urine tissue biopsy methenamine silver or periodic acid-Schiff stains show oval yeasts within macrophages Coccidioidomycosis Coccidioides immitis or Coccidioides posadasii demographics southwestern US Arizona, New Mexico, and southern California Central and South America risk factors earthquakes releases spherules from soil Presentation pneumonia dissemination to skin in 50% of patients erythema nodosum “desert bumps” erythema multiforme arthralgias “desert rheumatism” meningitis Imaging chest radiograph consolidations, hilar/mediastinal lymphadenopathy, or pleural effusions chest computed tomography (CT) multifocal ground glass opacities Studies detection of immunoglobulin M (IgM) in serum detection of antigen in serum tissue biopsy spherules (larger than RBCs) filled with endospores Blastomycosis Blastomyces dermatitidis demographics eastern US central US risk factors HIV infection Presentation majority are asymptomatic pneumonia severe chronic inflammatory lung disease dissemination to skin, often on the face verrucous skin lesions granulomatous nodules ulcers Imaging chest CT infiltrates without hilar lymphadenopathy cavitary lesions in chronic disease Studies tissue biopsy fungal stain shows broad-based budding yeast same size as red blood cells (RBCs) Paracoccidioidomycosis Paracoccidioides brasiliensis or Paracoccidioides lutzii also known as “South American blastomycosis” demographics Latin America male > female risk factors contact with soil Presentation severe chronic inflammatory lung disease pneumonia lymphadenopathy dissemination to skin, often on the face but can also affect mucous membranes verrucous skin lesions granulomatous nodules Imaging chest radiograph bilateral iniltrates without cavitation Studies tissue biopsy budding yeast "captain’s wheel” formation granulomas Sporothrix schenckii typically a localized infection but can present systemically localized disease can present with painful nodules traveling along lymphatic channels