Suspected Case of Histoplasmosis-Related Immune Reconstitution Inflammatory Syndrome Manifesting as Unilateral Pleural Effusion

Background: Histoplasmosis is a prevalent endemic mycosis that frequently causes opportunistic infections among individuals living with HIV (human immunodeficiency virus), and acquired immunodeficiency syndrome (AIDS). The initiation of antiretroviral therapy (ART) can result in a rare histoplasma-associated immune reconstitution inflammatory syndrome (IRIS) that may be difficult to distinguish between active progressive disease and inflammatory reaction to the medication. Case report: A 35-year-old male with newly diagnosed HIV and cervical biopsy-confirmed histoplasmosis was admitted from the emergency department with disseminated histoplasmosis for HIV antiretroviral treatment and antifungal treatment. Discharged after a 2-week inpatient treatment the patient returned 1 week later with a large left pleural effusion. Two liters of serosanguinous fluid were removed and all fluid cultures and cytology were negative. An extensive work-up remained negative, and given the timeline of presentation in relation to the initiation of ART, it was felt that this isolated left-sided pleural effusion was a manifestation of IRIS. Eventually, corticosteroids were given for IRIS and the patient improved and was discharged on long-term treatment. Conclusions: Immunocompromised subjects are at serious risk for a virulent, aggressive, rapidly advancing histoplasma infection and should be counselled accordingly. Any clinical signs or symptoms of organ system deterioration or compromise should be reported to the provider and a workup for histoplasmosis considered. In patients treated with antiretrovirals, IRIS is particularly confounding since it is difficult to differentiate from active disease. Using corticosteroids in already immunocompromised patients with an established fungal infection requires caution. Compliance with treatment is one of the most important components of care, especially considering the months of protocol.