Abnormal voiding parameters in children with severe idiopathic constipation.

OBJECTIVE

It is suggested that idiopathic constipation may associate with abnormal voiding parameters. In this study, we investigate the voiding parameters in children with constipation.

METHODS

Since 2010, seventeen consecutive children (12 boys, 5 girls) aged 5-17 (median = 14) with significant constipation according to Rome III criteria and who were not responding to conventional treatment (diet, laxatives & bowel training) for over 6 months were recruited. The rectal diameter (RD) was measured by transpubic ultrasonography (USG), RD >3.5 cm was considered as dilated. Each patient had uroflow measurement and bladder USG done to measure the maximal flow rate (Vmax), voided volume (VV), and post-void residual urine (PVR). Abnormal voiding parameters were defined as Vmax <12 ml/sec, VV <65 or >150% of age-adjusted expected bladder capacity (EBC) and/or PVR >20 ml.

RESULTS

Rectal diameter ranged from 1.7 to 8.2 cm (median = 3 cm) and was abnormally dilated in eight children. Vmax was normal in all children (median = 23.7 ml/sec). Voided volume ranged from 30 to 289% of EBC and was abnormal in six children (35.5%). Post-void residual urine varied from 0 to 85 ml and was abnormal in six (35.5 %) children. Three children (17.6 %) had both abnormal VV and PVR. On the whole, the prevalence of abnormal voiding parameters in constipated children was 52.9 %. Mean RD in normal and abnormal parameters groups was 2.8 and 4.7 cm, respectively. Rectal dilation was associated with abnormal voiding parameters (p = 0.015).

CONCLUSION

Abnormal voiding parameters including voided volume and post-void residual urine are prevalent in constipated children. Dilated rectum is associated with abnormal voiding parameters.