Diagnosis of a single kidney on antenatal scan is not uncommon. Unilateral renal agenesis (URA) is reported to occur in 1:1500 prenatal ultrasound studies.¹ Other causes of single kidney are less common and include unrecognised ectopic kidney and fetal involution of a previous unilateral multicystic dysplastic kidney.² Forty eight per cent of children with URA are reported to have other urological anomalies, with more than half demonstrating vesicoureteric reflux.³ Adult patients with URA are reported to have an increased incidence of proteinuria, hypertension, and renal insufficiency.⁴

We conducted a survey to examine how otherwise healthy babies born with antenatally diagnosed healthy looking single kidney are managed in the United Kingdom. A questionnaire was sent to a 219 consultant paediatricians, one in each hospital. Questions were related to postnatal management, including the need for investigations, antibiotic prophylaxis, and follow up.

We received 138 responses (63%). Most of the respondents (n = 131, 94%) agreed for the need for a postnatal ultrasound. Sixty eight (49%) would perform further investigations such as micturating cystogram (MCUG) and/or DMSA/MAG3 if the ultrasound scan was abnormal. However, a significant number (n = 60, 43%) would perform further studies irrespective of the ultrasound result. About half the consultants (n = 65, 47%) would offer their patients prophylactic antibiotics until the radiological assessment excludes the possibility of associated renal anomalies, contralateral ectopia, and residual renal tissue. Forty eight respondents (35%) will follow up their patients for at least one year (30 suggested five years or more), 50% of whom will perform MCUG and/or DMSA/MAG3 as a routine. Ten (7%) will refer to the specialist services and the rest will discharge their patients if the radiological investigations are normal.

This survey demonstrates wide variation in the practice among UK paediatricians in the management of antenatally diagnosed single kidney and suggests the needs for development of national guidelines.