Video cystometry in young infants with renal dilation or a history of urinary tract infection

Cystometry is increasingly being used in infants to diagnose bladder dysfun ction. However, infantile urodynamic patterns have not been fully establish ed. In this study we investigated the urodynamic patterns in young infants with renal dilation or a history of urinary tract infection, but with no ap parent lower urinary tract symptoms. We use video cystometry with simultane ous perineal EMG recording. Thirty-five infants (27 male and 8 female) with congenital renal dilatation or a history of urinary tract infection at age 2 days to 24 months old were involved. We found that detrusor instability occurred in 8.6% of these subjects. Bladder capacity increased with age but less than would nomally be expected. An intermittent voiding pattern was o bserved in 57% (20/35) of subjects and was characterize by a single or recu rring increase in sphincter activity with a simultaneous rise in the voidin g detrusor pressure curve. The maximum voiding detrusor pressure wit pelvic floor overactivity was significantly higher than that with no pelvic floor overactivity (105 +/- 44 cmH(2)O vs 69 +/- 22 cmH(2)O, P<0.001). The media n post-voiding residual volume was 2 (range 0 to 65) ml. We conclude that i n infants with no apparent lower urinary tract symptoms, bladder instabilit y is uncommon, and the capacity is lower than the normally expected range; an intermittent voiding pattern is common and the residual urine volume sho wed great variation. This probably represents an immature detrusor-sphincte r function.