[Diagnostic management of primary megaureter : Voiding cystourethrography obligatory, scintigraphy useful?]

A primary, congenital megaureter means a dilatation of the ureter with a ureteric diameter ≥7 mm due to a structural or functional obstruction of the ureterovesical junction and represents the second most likely cause of neonatal hydronephrosis. Conservative management is the primary treatment option for many patients due to a high spontaneous remission rate of up to 85%. Concerning diagnostic management, meticulous and repeat postnatal evaluation by ultrasound is mandatory to identify patients who are at risk of renal deterioration. Routine voiding cystourethrography or contrast-enhanced voiding urosonography is currently recommended for all patients to detect vesicoureterorenal reflux and other concomitant pathologies. The relevance of the additional information provided by this examination must be critically questioned considering the lack of clinical consequences. Moreover, the question arises as to whether these examinations should be prolonged until clinical symptoms occur. Nevertheless, a subvesical obstruction should still be ruled out for male patients with a bilateral megaureter. The same critical discussion is necessary for the routine use of diuretic renography in patients with primary megaureter. In principal, this examination is used to determine the global as well as the split renal function and in addition is considered to offer an evaluation of the extent of obstruction. Similarly, the question arises of whether this examination should be mandatory for every child with a primary megaureter or whether the decision should be based on the extent of the upper urinary tract dilatation. The trend of diagnostic management should go towards individualized and risk-adapted diagnostic measures.