RESUMO
OBJECTIVE: Since 1995 we have, at our centre, adopted a selective approach to performing micturating cystourethrograms (MCUGs) on patients with antenatally diagnosed hydronephrosis. This study reviews the outcome of this policy. METHODS: We carry out MCUGs only if any of the following features are present on ultrasound: bilateral hydronephrosis, ureteric dilatation, renal scarring, bladder wall thickness greater than 5mm, or presence of a duplex system or ureterocele. Patients with simple unilateral hydronephrosis are excluded, and are managed with 6 months' trimethoprim prophylaxis and ultrasound surveillance with a minimum of 3 years' follow up. RESULTS: Fifty-five patients were referred with an antenatal diagnosis of hydronephrosis between 1999 and 2002; 26 (47%) did not have an MCUG. Of these, five had increasing hydronephrosis and required surgery for pelvi-ureteric junction obstruction, and three had a multicystic dysplastic kidney on postnatal scanning. In the remaining 18 patients, the hydronephrosis resolved spontaneously, with no renal scars or asymmetry. During follow up, none of these patients had a urinary tract infection. CONCLUSION: We believe that vesico-ureteric reflux in most antenatally diagnosed hydronephrotic kidneys is physiological rather than pathological, and resolves with time without causing long-term renal damage. This is a separate entity from, rather than a precursor of, the pathological symptomatic refluxing kidney in older, mainly female children. Taking a more conservative approach to the postnatal investigation of antenatally diagnosed hydronephrotic kidneys has not resulted in any missed damaged kidneys, but has reduced the number of invasive investigations performed. A careful protocol and detailed postnatal ultrasonography are important to prevent missed pathological cases.
