Imaging after urinary tract infection in male neonates.

OBJECTIVE: To assess the frequency of urinary tract anomalies in male neonates <8 weeks old who presented with urinary tract infection (UTI), and to evaluate a suitable imaging approach after the initial infection.

DESIGN: During a period of 4.5 years, from July 1994 through December 1998, 45 male neonates <8 weeks old (range: 5-56 days; mean: 23.77 days) with UTI were hospitalized. All patients had an ultrasound (US) and a voiding cystourethrogram (VCUG), except 1 neonate in whom VCUG was unsuccessful because of technical problems. A dimercaptosuccinic acid (DMSA) scan was recommended to all patients but was performed only in 30 of 45, most of them with an abnormal VCUG. The renal scan was performed at least 4 months after the UTI.

RESULTS: Urinary tract abnormalities were observed in 22 of 45 male neonates. Nineteen had vesicoureteral reflux (VUR), 1 had VUR and a double collecting system, 1 had VUR and a posterior urethral valve, and 1 had an ureteropelvic junction stricture. Renal atrophy or scars, as demonstrated by DMSA scan, were detected almost exclusively in neonates with VUR grade 3 and above. Only 1 neonate with VUR grade 1 had a pathologic DMSA, and the US of this male also demonstrated renal atrophy. Escherichia coli was the pathogen in 62% (28 of 45), and 9 boys had bacteremia.

CONCLUSION: We suggest that US and VCUG should be performed routinely after the initial UTI in male neonates. Renal scan should be reserved for those cases in which the US suggests renal parenchymal damage or when VCUG detects VUR grade 3 and above.