ABSTRACT
Urinary tract infection is one of the causes of acute renal failure. But it has been reported rarely, so we must consider another etiologies before diagnosis. Abdominal ultrasonogram is a good non-invasive technique for radiologic diagnosis or for differential diagnosis, but it's possible that tiny abscesses and small lesions of focal bacterial nephritis might be missed. CT is the best radiologic method to diagnose renal lesion, especially acute bacterial nephritis. Nevertheless, CT has several problems, including contrast-induced nephropathy, exposure to radiation. We experienced a severe form of anuric acute renal failure secondary to acute bacterial nephritis due to E. coli infection. The patient's renal lesion was not visualized on the ultrasonogram and his uremic symptom was severe. So we decided to do a kidney biopsy to find another possible cause of acute renal failure. The renal biopsy finding showed acute bacterial nephritis, and abdominal CT reconfirmed it. His serum creatinine increased to a maximum 8.5 mg/dL, but decreased to 1.24 mg/dL through continuous antibiotic therapy. We emphasize that urinary tract infection is not a rare cause of acute renal failure any more, and that positive diagnositic approaches, including kidney biopsy, are important for accurate and early diagnosis.