Acute kidney injury in a diabetic man after contrast CT

Mr. AB, a 72-year-old man with type 2 diabetes, hypertension, and dyslipidaemia, presented to the emergency department with nausea and malaise two days after a contrast-enhanced CT scan. His regular medications were metformin 1000 mg twice daily, lisinopril 20 mg once daily, and atorvastatin 40 mg once daily, which he had taken for several years. On day 0, he received intravenous iohexol 300 mg iodine/ml, 100 ml, during a CT scan of the abdomen and pelvis performed to investigate abdominal pain. His serum creatinine was 130 µmol/L before the scan. On day 2, his creatinine was 290 µmol/L. He had no clinical signs of dehydration, hypotension, or infection. Urinalysis showed no blood, protein, or leucocytes. Renal ultrasound showed normal kidneys without obstruction. He had continued taking all his medications, including metformin, after the scan. On admission, metformin and lisinopril were withheld, and intravenous fluids were administered. Over the next five days, his serum creatinine gradually fell to 170 µmol/L. A review of his drug history noted that he had tolerated lisinopril and atorvastatin indefinitely, and there was no recent change. The differential diagnosis included contrast-induced nephropathy, acute interstitial nephritis from a drug, and progression of diabetic nephropathy. No rechallenge was performed.