A Curious Case of Blastomyces Osteomyelitis

Blastomycosis is an uncommon disease caused by the dimorphic fungus, Blastomyces dermatitidis, often found in endemic regions of Midwestern America. It can be found in forested, sandy soils, decaying vegetation, rotting wood near water sources, and even in bird feces. Most commonly, blastomycosis manifests as a pulmonary infection presenting as pneumonia, or in severe cases, respiratory distress syndrome (ARDS). Dissemination to the bone is less common but osteomyelitis of the lower thoracic and lumbar spine, ribs, skull, and long bones have been most frequently reported. Disseminated infection to the genitourinary system commonly manifests as prostatitis or epididymo-orchitis in men and as an endometrial infection or tubo-ovarian abscess in women. In the nervous system, blastomycosis can manifest as meningitis or with a cranial abscess. Having a high degree of clinical suspicion and obtaining a detailed medical and social history is important for making a diagnosis. Culturing a specimen will provide a definitive diagnosis. Sputum or tissue specimens stained in 10% potassium hydroxide under microscopy will reveal the classic appearance of B. dermatitidis (broad-based budding with a double-contoured cell wall). In mild to moderate disease without dissemination, itraconazole is the treatment of choice. In severe, life-threatening cases, patients with CNS involvement or in immunocompromised individuals, amphotericin B is the preferred initial drug of choice. We present an interesting case of a 42-year-old African-American male with no significant past medical history who was admitted initially for suspicion of cellulitis/septic arthritis and was started on broad-spectrum antibiotics. However, he was eventually found to have Blastomyces osteomyelitis.