Intravenous Iron Induced Pigment Nephropathy Leading To Severe Acute Necrosis: A Rare Cause of AKI

Abstract Ferric carboxymaltose (FCM) is widely used for the treatment of iron deficiency anemia. Although generally safe, severe adverse reactions including muscle injury and pigment induced acute kidney injury (AKI) are rare but lead to clinically significant complications whenever they occur Case Summary: We present a middle aged male who developed severe rigor, diffuse myalgia, dark colored urine, and oliguria on administration of ferric carboxymaltose which was administered by the local practitioner without any lab investigation beforehand. On admission to our center he presented with aforementioned symptoms pointing towards advanced renal failure, hyperkalemia, and with markedly elevated CPK and LDH levels, signifying rhabdomyolysis. Urine microscopy showed no RBCs but the dipstick test was positive for blood, signifying myoglobinuria. Serum myoglobin was elevated with normal haptoglobin. The patient required multiple sessions of hemodialysis. A renal biopsy was performed to know the cause of persistent anuria which confirmed acute tubular necrosis with pigment-laden epithelial cells. He gradually regained urine output by day 10 and achieved complete renal recovery by 3 weeks.