THE CASE: A 10-year-old boy presents to your office with sharp right-sided flank pain. The pain began the night before, and the child could produce only a few drops of urine the next morning. Ten days earlier, he had several episodes of vomiting and diarrhea, which resolved within 3 days. Seven days before presentation, he had 1 episode of dark brown urine. He has had no fever, chills, sore throat, dysuria, frequency, abdominal pain, scrotal swelling or pain, or rash. He denies recent trauma and medication use.
Medical history is significant for surgical removal of a right undescended testicle. The child’s growth has been below the 3rd percentile. He has no history of urinary tract infections (UTIs) or kidney disease or any family history of genitourinary problems.
The child appears well and comfortable. He is afebrile. Blood pressure, heart rate, and respiration rate are normal. The abdomen is soft and nontender. No peritoneal signs, hepatosplenomegaly, or mass is noted. Percussion demonstrates moderate right costovertebral angle tenderness. External genital findings are otherwise normal. The boy is Tanner stage II. A clean catch urine reveals 30 to 100 red blood cells and 0 to 2 white blood cells.
A complete blood cell count with differential shows no leukocytosis or left shift, and no anemia or thrombocytopenia. A basic metabolic panel reveals normal blood urea(Drug information on urea) nitrogen, creatinine, and electrolyte levels. A renal ultrasonogram is shown.
What do you suspect is the cause of this child’s symptoms?
•Urinary tract infection
•Ureteropelvic junction obstruction
(Answer and discussion begin on the next page.)