Histoplasmosis – An Infrequent Cause of Fever

Histoplasmosis is a systemic fungal infection caused by Histoplasma capsulatum, commonly seen in immunocompromised or elderly individuals with environmental exposure. A 65-year-old male taxi driver from Gurugram, with a history of diabetes mellitus and hypertension, presented with a 10-day history of highgrade fever, nausea, anorexia, weakness, and unintentional weight loss. Laboratory investigation showed anaemia (haemoglobin [Hb] 9.2 g/dL), hyponatraemia (sodium [Na] 123.7 mEq/L), elevated liver enzymes (alkaline phosphatase [ALP] 576 U/L, gamma-glutamyl transferase [GGT] 207 U/L), hypoalbuminaemia, and markedly raised C-reactive protein (CRP) 157.7 mg/L. Imaging revealed right middle zone consolidation, mild pleural and pericardial effusions, and hepatosplenomegaly. Serological and microbiological tests for dengue, malaria, typhoid, and viral hepatitis were negative. The patient showed partial improvement with antibiotics; however, fever recurred, and bone marrow aspiration (BMA) demonstrated intracellular yeast-like organisms morphologically consistent with H. capsulatum.