Question
Mycetoma
Answer
Mycetoma is a chronic, slowly progressive granulomatous infection of subcutaneous tissue, most often affecting the foot (“Madura foot”), caused by true fungi (eumycetoma) or filamentous aerobic actinomycete bacteria (actinomycetoma) — distinguishing between the two is essential since treatment differs completely.
Clinical presentation: a classic triad of tumefaction (swelling), multiple sinus tracts, and discharge containing grains — eumycetoma grains typically black/dark, actinomycetoma grains typically white, yellow, or red.
Causative organisms: Eumycetoma — Madurella mycetomatis (most common); Actinomycetoma — Nocardia, Actinomadura, Streptomyces somaliensis.
Laboratory diagnosis: direct examination of grains (broad, septate fungal hyphae for eumycetoma; fine, thin, branching bacterial filaments for actinomycetoma); histopathology; culture; imaging for bone involvement.
Treatment: actinomycetoma — prolonged combination antibacterial therapy; eumycetoma — antifungal therapy (itraconazole) often with surgical excision, poorer prognosis.