Ten days after a kidney transplant, a 32-year-old man returns to the hospital with symptoms of fever, and decreased urine output. He reports no cough, sputum, or dysuria. An ultrasound of the transplant kidney shows allograft enlargement. Which of the following is the most likely diagnosis?

Renal scans initially show a reduction in excretion with cortical retention. This is the most common type of rejection. Most acute rejections will respond to immunosuppressive agents if diagnosed early. In contrast, immediate nonfunction of a graft can be caused by damage to the kidney during procurement and storage. Such problems are becoming less frequent. Obstruction, vascular compression, and ureteral compression are other causes of primary nonfunction of a renal graft.