This woman delivered a 7 lb, 3 oz otherwise healthy male infant. Postnatal sonography confirms the presence of unilateral hydronephrosis. What further evaluation do you recommend?
Careful physical examination with an emphasis on observing the infant’s active voiding is an important first step. The infant should be started on antibiotic prophylaxis as the incidence of urinary tract infection is approximately 3% to 4% in the first 6 months of life. A voiding cystourethrogram (VCUG) and nuclear renogram (DTPA or MAG 3) should also be scheduled. Recent work suggests a conservative approach to nuclear renography in patients with mild hydronephrosis.