Urodynamic patterns in infants with normal lower urinary tracts or primary vesico-ureteric reflux

Abstract

Objective. To compare bladder function in infants with primary vesico-ureteric reflux (VUR) and those with normal lower urinary tracts. Patients and methods. The study comprised 42 patients (36 males) with VUR (grades III to V) and 21 (16 males) without VUR (mean age in both groups, 6 months). Intravesical catheters were placed suprapubically under general anaesthesia and, after at least 24 h, natural-filling urodynamics were monitored for three or more filling and voiding cycles. Results. Various urodynamics patterns were defined: for infants without VUR these were either normal or normal-immature (discoordinated micturition) and none showed features indicating abnormal bladder function. By comparison, 24 of 47 infants with VUR showed abnormal urodynamic patterns (57%, 95% confidence interval 41% to 72%, P < 0.001). Seven (17%) were defined as unstable with small voided volumes, live (12%) had inadequate voiding dynamics, 10 (24%) showed a markedly dyssynergic pattern and two (5%) had obstructive patterns. The unstable, inadequate and obstructive patterns occurred only in boys. Detrusor activity during the filling phase occurred in 14 infants (13 boys) with VUR and in only one without VUR, when it was trivial. Post-void residual volumes of > 30% capacity were seen only in the VUR group (in 24 patients). There were 18 infants with VUR that showed the normal or immature urodynamics patterns, but for the 14 males the voiding pressures were higher than for those without VUR (mean maximum detrusor pressure, 161 and 117 cmH2O, respectively; P < 0.02). Conclusions. There is an association between abnormal urodynamic variables and a diagnosis of primary VUR in young infants (notably males) that may have important implications for concepts about the genesis and persistence of VUR.