An 18-year-old woman was admitted to the hospital with 2 days of severe right flank pain, fever, and vomiting. She had no significant medical history and denied any urinary symptoms, gross hematuria, or kidney stone disease. Physical examination revealed an oral temperature of 103.1 °F, pulse rate of 90 beats/min, and blood pressure of 110/70 mm Hg. She had right costovertebral angle tenderness. Other systems were unremarkable.