A 38-year-old man was admitted to the hospital because of abrupt left flank pain. He had no fever and physical examination revealed tenderness of the left costovertebral angle. Laboratory data revealed white blood cell 16,060/μL, C-reactive protein 0.93 mg/ dL. Urinalysis showed more than 1/2 red cells per high-power field with severe proteinuria (4+). Enhanced computed tomography (CT) showed t...