**4.2 Postnatal diagnosis**

In the neonate with a suspected urological obstruction, multiple modalities may be needed for full evaluation. Renal ultrasound and voiding cytourethrogram usually play important roles in postnatal assessment of these patients, and in some cases CT, MRI, diuretic renography, urodynamic studies, or cystoscopy may be useful.

If not detected prenatally, congenital obstructive nephropathy may present in the neonate, infant, child, adolescent or adult with poor urine output, weak urine stream, abdominal distention, palpable abdominal or flank mass, pain, incontinence, urinary tract infection, hematuria, altered serum chemistries, or as an incidental finding on imaging studies.
