The key is in the details: a case of disseminated histoplasmosis

Case description: A 39-year-old HIV-positive Hispanic gentleman presented to the emergency department with a four-day history of altered mental status, pyrexia, mild non-productive cough, nausea and vomiting on a background of night sweats, chills, weight loss and diarrhoea. The patient had a history of non-compliance with his antiretroviral therapy, and of tobacco, alcohol and cocaine use. He was a lifelong gardener, born in Mexico but living in southern California for 19 years. On examination he was febrile, wasted and disoriented. A number of skin lesions were appreciated throughout his body. Laboratory studies demonstrated pancytopaenia and severe immunosuppression; however, imaging, serology, cultures and a bone marrow biopsy were unremarkable. Despite antibacterial, antiviral and antifungal treatment, he continued to deteriorate clinically. Thirteen days into his admission, his blood and bone marrow fungal cultures tested positive for Histoplasma capsulatum. His final diagnosis was disseminated histoplasmosis involving multiple organ systems, which responded rapidly to treatment with intravenous liposomal amphotericin B.

Discussion: This case illustrates the challenges faced in the diagnosis of disseminated histoplasmosis in a patient with advanced HIV, including vague symptomatology, the presence of multiple HIV-related comorbidities, non-reactive serology, and delay due to slow-growing fungal cultures. Most importantly, this case highlights the importance of a thorough history and examination in eliciting the clues to diagnosis in the face of these challenges