Pathogenesis of enuresis: Towards a new understanding.

Enuresis was historically viewed as a primarily psychiatric disorder, but this understanding has changed dramatically since the end of the last century, when it became clear that somatic factors, such as nocturnal polyuria as a result of vasopressin deficiency, nocturnal detrusor overactivity and high arousal thresholds, all play a crucial role in enuresis pathogenesis. It has also become clear that enuresis is inherited in the majority of cases, although the correlation between genotype and enuretic phenotype is not straightforward. The standard view of enuresis as being the result of either (i) nocturnal polyuria and high arousal thresholds; or (ii) nocturnal detrusor overactivity and high arousal thresholds has become well-established, but further research now complicates the picture. First, psychological/psychiatric problems are overrepresented in enuresis, and might in a minority of cases have a causal or aggravating role. Second, nocturnal polyuria is not always linked to vasopressin deficiency. Third, nocturnal detrusor overactivity is in itself pathogenetically heterogeneous, and could be linked to constipation. Fourth, the sleep of enuretic children might be "deep," but possibly also disturbed (by obstructed airways or a distended or contracting bladder). These children might have high arousal thresholds because of the enuresis instead of the other way around. The same might possibly be said about nocturnal polyuria. Taking these new insights into account, a new model of enuresis pathogenesis is presented, which is more complicated but hopefully also more true than the standard consensus.