Is there an association between functional bladder outlet obstruction and Down's syndrome?

The incidence of urinary tract abnormalities in patients with Down's syndrome (DS) is estimated to be 3-7%. Abnormalities included are renal hypoplasia, renal cysts, ureterovesical and ureteropelvic junction obstruction and, more recently, an association between males with DS and the non-neurogenic neurogenic bladder has been reported. Based on clinical experience, the hypothesis is tested that patients with DS have functional bladder outflow obstruction secondary to detrusor sphincter dyssynergia.

This study comprised three parts: an initial retrospective review of case notes of existing patients, followed by a prospective community-based study of all patients with DS to assess the incidence and types of bladder dysfunction, and a final hospital-based assessment where a problem was identified following return of the questionnaire.

The retrospective study identified a high potential for renal injury with three out of seven patients requiring urinary diversion for dilated upper tracts secondary to bladder outflow obstruction. The prospective study identified a high incidence (77%) of bladder dysfunction with 68% having a history of wetting.

There is a potentially serious problem in children with DS that is not widely appreciated. We recommend that, at the very least, such children have a detailed history of bladder function taken, and where a problem is detected a urinary tract ultrasound scan should be performed.