A Rare Case of Tuberculosis Associated Thrombotic Microangiopathy with Diagnostic Challenges

Thrombotic microangiopathy (TMA) is a clinicopathological entity characterized by microangiopathic hemolytic anemia, thrombocytopenia, and organ dysfunction, particularly renal involvement. While commonly associated with Shiga toxin, complement dysregulation, malignancy, or drugs, tuberculosis-associated TMA is exceedingly rare and diagnostically challenging. We report the case of a 13-year-old female who presented with intermittent fever with chills for 20 days, diffuse abdominal pain for 15 days, and features of intestinal obstruction for 3?4 days, along with decreased urine output for 2 days. There was no history of weight loss, altered appetite, gastrointestinal or urinary bleeding, altered sensorium, long-term medication use, or past tuberculosis exposure. On examination, she was febrile (100.4 ?F), hemodynamically stable, with pallor and bilateral pedal edema. Abdominal examination revealed right iliac fossa tenderness, distension, and sluggish bowel sounds. Laboratory evaluation showed neutrophilic leukocytosis, macrocytic anemia (Hb 6.7 g/dL, MCV 105), thrombocytopenia (25, 000/?L), indirect hyperbilirubinemia, elevated LDH (>1000 IU/L), uric acid 9.3 mg/dL, and renal dysfunction (urea 131 mg/dL, creatinine 4.9 mg/dL). Urinalysis revealed 2+ proteinuria with 1.5 g/day proteinuria and 10?20 pus cells/hpf. Imaging and ascitic fluid findings, along with a positive TST (25 mm), supported a diagnosis of abdominal tuberculosis, and anti-tubercular therapy (ATT) was initiated. Autoimmune, viral, and parasitic workups were negative. Renal biopsy was deferred initially. One-month post-discharge, she had recurrent anemia, worsening renal function, and increased proteinuria (2.9 g/day). Schistocytes (>10/hpf) were identified, and renal biopsy confirmed TMA. She was treated with plasma exchange alongside ATT. This case highlights tuberculosis as a rare but significant secondary cause of TMA. Early suspicion and renal biopsy in deteriorating patients are vital for diagnosis and management.