A study of progression of renal disease in infants with abnormal antenatal renal sonogram

Background: Antenatally detected renal abnormalities are common. Antenatal hydronephrosis may be transient and physiologic or may indicate congenital anomalies of the kidney and urinary tract (CAKUT) requiring postnatal evaluation and intervention. The challenge is to identify clinically significant disease while avoiding unnecessary investigations. Objectives: To determine the proportion of neonates with urinary tract abnormalities and to study the prognosis and outcome of antenatally detected renal anomalies. Methods: This prospective observational study was conducted in the neonatal intensive care unit of M.O.S.C. Medical College and Teaching Hospital, a tertiary care centre, from August 2017 to July 2018. Neonates with an abnormal antenatal renal sonogram were enrolled. Antenatal findings, postnatal ultrasonography, renal function, urinary tract infection, growth, blood pressure and need for further urological evaluation or surgery were recorded. Follow-up ultrasonography was performed at 1, 3 and 6 months, with additional evaluation as clinically indicated. Results: A total of 3005 pregnancies were screened for abnormal antenatal renal sonography and 90 neonates met the study inclusion criteria. Males comprised 65 (72.2%) and females 25 (27.8%) of enrolled neonates. The mean gestational age at diagnosis was 33.3 weeks. Hydronephrosis was the most common antenatal finding, occurring in 50 (55.5%) neonates: mild in 38 (42.3%), moderate in 10 (11.2%) and severe in 2 (2.2%). Thirty-one neonates had significant uropathy, 29 had transient hydronephrosis and 30 had non-significant findings. Among 50 clinically treated children without primary vesicoureteral reflux, renal pelvic diameter resolved in 37 (74%) after a median follow-up of 6 months. Maternal age, sex, side of affection and amniotic fluid index were not significant predictors of significant postnatal uropathy. Four infants (4.4%) had acute kidney injury and two (2.2%) had urinary tract infection. Six infants underwent micturating cystourethrogram; one had grade V vesicoureteral reflux and one had posterior urethral valve. Five underwent DTPA scanning, with one showing reduced cortical function and requiring surgical correction. Two infants died in the neonatal period, both with severe antenatal renal disease and oligohydramnios. Conclusion: Most infants with isolated antenatal hydronephrosis had a favourable short-term outcome. Mild and moderate renal pelvic dilatation frequently resolved or remained under surveillance, while severe disease was more likely to require detailed urological evaluation and intervention. Postnatal assessment should therefore be individualized according to antenatal severity and associated abnormalities, with continued clinical surveillance during infancy.