Myoglobin cast nephropathy in a kidney transplant patient with normal creatine kinase.

Delayed graft function in kidney transplant recipients is a known complication associated with increased risk of acute rejection and reduced transplant survival after 1 year. There are multiple risk factors, including prolonged cold ischemia time, donor age, and cause of donor's death. Major causes of delayed graft function are acute kidney injury in the donor, often from prolonged terminal ischemia, reflected by acute tubular injury in the recipient. However, the differential diagnosis of delayed graft function includes acute rejection, recurrence of the primary glomerular diseases, and other less commonly encountered conditions. A transplant kidney biopsy usually is required to elucidate the correct cause and initiate the right treatment, which is crucial for transplant survival. We report a case of a transplant recipient who developed delayed graft function due to an uncommon cause. After correct diagnosis, the patient's transplant function improved.