Concurrent Histoplasmosis & Blastomycosis in a Young Woman.

Abstract

Background: Histoplasmosis capsulatum and Blastomyces dermatitidis are fungi that are uniquely distributed across the United States. Co-infection with both fungi remains uncommon. The literature review of coinfection was limited to three cases. Only two cases were recorded in humans. Infection can yield symptoms ranging from asymptomatic to life-threatening. On radiographic imaging, diffuse reticulonodular infiltrates with hilar or mediastinal lymphadenopathy can be seen. Management depends on the severity of the disease and the patient's immune state.

Case description: A 35-year-old female with a medical history significant for HIV and substance use disorder presented to the hospital with severe lower abdominal pain, weakness, and unintentional weight loss. Her symptoms persisted and evolved to include dyspnea and high fevers. Imaging with chest CT revealed diffuse miliary lung patterns. Confirmation of histoplasmosis was noted by in-house blood cultures. Additional testing via send-out laboratory confirmed the presence of Blastomyces dermatitidis antigen. Her hospital course was complicated by acute hypoxic respiratory failure and the patient was intubated. Despite aggressive antibiotic and antifungal therapy, the patient's condition continued to decline. The patient's family decided to transition her care to comfort measures and the patient was palliatively extubated, expiring shortly afterwards.

Conclusion: Current treatment of histoplasmosis in immunocompetent individuals depends on the duration of the disease. Acute infections do not warrant treatment. If symptoms persist, a three-month course of itraconazole is recommended. Amphotericin B is considered in patients unable to take itraconazole or for those with severe disease. Blastomycosis ranges from asymptomatic to a deadly pulmonary infection. While spontaneous remission of mildly symptomatic blastomycosis can occur, treatment with itraconazole is often recommended. Amphotericin B is reserved for severe pulmonary infection, disseminated blastomycosis, or central nervous system blastomycosis. Immunocompromised patients represent a population at significantly elevated risk for disseminated fungal disease as well as severe pulmonary infection from fungal disease.