HLH-Like Hyperinflammation and Biopsy-Proven Acute Tubulointerstitial Nephritis in Probable Typhoid Fever: A Rare Immune-Mediated Multisystem Presentation

Typhoid fever is a systemic infection caused by Salmonella enterica serotype Typhi and remains an important public health concern in developing countries. Although it commonly involves the gastrointestinal and reticuloendothelial systems, rare immune-mediated complications with multisystem involvement have been described. We report a case of a 19-year-old male presenting with persistent high-grade fever, cytopenias, marked hyperferritinemia, acute kidney injury, and systemic inflammation suggestive of an HLH-like hyperinflammatory state associated with probable enteric fever. The patient had fever, splenomegaly, thrombocytopenia, elevated ferritin (>3000 ng/mL), hypofibrinogenemia, and mild hypertriglyceridemia, but did not fulfill complete HLH-2004 diagnostic criteria. Blood cultures were negative, possibly due to prior antibiotic exposure, while a strongly positive typhoid serological titre in the appropriate clinical and epidemiological context supported probable enteric fever. Renal biopsy demonstrated acute tubulointerstitial nephritis with acute tubular injury and minimal change disease-like glomerular alterations, suggesting an immune-mediated renal process. The patient was treated with intravenous ceftriaxone and corticosteroids due to persistent systemic inflammation and progressive renal involvement, resulting in complete clinical and biochemical recovery. This case highlights the importance of recognizing infection-associated HLH-like hyperinflammation and immune-mediated renal injury in patients with probable typhoid fever presenting with persistent fever, cytopenias, and acute kidney injury. Bangladesh Med J. 2026 Jan; 55(1): 57-62