Miliary Patterns on Computerized Tomography Imaging of Chest in Immunocompromised Patient: Unveiling Disseminated Histoplasmosis

BACKGROUND Disseminated histoplasmosis is a rare fungal infection caused by dimorphic fungus Histoplasma capsulatum. Immunocompetent patients are usually asymptomatic or have self-limiting disease; however, immunocompromised patients present as disseminated infection. Our case report includes an immunocompromised host with atypical presentation and imaging findings consistent with a miliary pattern that did not fit the classical clinical picture of disseminated histoplasmosis, causing a delay in the diagnosis. CASE REPORT We report a case of a patient who presented with shortness of breath, nonproductive cough, low-grade fevers, and weight loss, who received a diagnosis of disseminated histoplasmosis, with an underlying immunocompromised state. Due to the ineffectiveness of initial management with empiric antibiotics, imaging with computed tomography (CT) of the chest was done, revealing miliary disease, and tuberculosis was first in the differential diagnosis. She had a positive histoplasma urine antigen, and bronchial alveolar lavage fluid tested positive for histoplasma antigen, confirming miliary histoplasmosis. Her CT of the abdomen/pelvis showed multiple lesions in the spleen and adrenal glands bilaterally, concerning for disseminated histoplasmosis, which was treated with amphotericin B, followed by itraconazole. CONCLUSIONS Disseminated histoplasmosis is a rare and challenging diagnosis; there should be a low suspicion for histoplasmosis in patients treated with tumor necrosis factor inhibitors, as mortality is high in such cases. Despite the inability to detect antibodies in immunocompromised patients, definitive diagnostic tests must be considered through culture and histopathology, the criterion standard tests, before excluding infectious causes. This case highlights the challenges faced in diagnosing and treating miliary histoplasmosis in immunocompromised patients.