Progressive disseminated histoplasmosis: The experience in one non-endemic medical center

Histoplasmosis, the most common endemic mycosis in North America, presents in a myriad of ways, spanning the spectrum from self-limiting pneumonia to progressive disseminated histoplasmosis (PDH). Toward better describing contemporary histoplasmosis syndromes, risks, and outcomes, this single-center retrospective cohort study was performed (2009–2019). The population who developed PDH was similar to that with other forms of histoplasmosis (OFH) except for higher rates of preexisting immunocompromising conditions (91.3% vs. 40%, P < .001) and a trend toward receiving more chronic immunosuppression (65.2% vs. 33.3%, P = .054) compared to those with OFH. Diagnosis was most frequently achieved by urinary or serum antigen positivity. People with PDH more frequently tested positive compared to those with OFH, but negative tests did not rule out histoplasmosis. Median time to diagnosis was prolonged among people with both PDH and OFH (32 vs. 31 days, respectively). Following diagnosis, people with PDH received more liposomal amphotericin (78.3% vs. 20%, P < .001). Subsequent survival at 90 and 365 days and treatment response were similar in both groups. Patients with PDH were more often hospitalized (95.7% vs. 60%, P = .006); however, once admitted, there were no differences in hospital length of stay or intensive care unit admission rate. The challenges of diagnosing histoplasmosis based on clinical presentation alone highlight the need for heightened awareness of these entities especially given the recent reports on expanded endemicity and delays in diagnosis.