Voiding dysfunction due to detrusor underactivity: an overview.

Detrusor underactivity (DUA) is defined as a voiding contraction of reduced strength and/or duration, which prolongs urination and/or prevents complete emptying of the bladder within a 'normal' period of time. This issue is associated with voiding and postmicturition urinary symptoms, and can predispose to urinary infections and acute urinary retention. The aetiology of DUA is influenced by multiple factors, including ageing, bladder outlet obstruction, neurological disease, and autonomic denervation. The true prevalence of this condition remains unknown, as most data come from referral populations. Urodynamic testing is used to diagnose the condition, either by assessing the relationship between bladder pressures and urinary flow, or by interrupting voiding to measure detrusor pressure change under isovolumetric conditions. Current treatments for DUA have poor efficacy and tolerability, and often fail to improve quality of life; muscarinic receptor agonists, in particular, have limited efficacy and frequent adverse effects. Bladder emptying might be achieved through Valsalva straining, and intermittent or indwelling catheterization, although sacral nerve stimulation can reduce dependency on catheterization. Novel stem-cell-based therapies have been attempted; however, new drugs that increase contractility are currently largely conceptual, and the complex pathophysiology of DUA, difficulty achieving organ specificity of treatment, the limited availability of animal models, and the subjective nature of current outcome measures must be addressed to facilitate the development of such agents.