Nocturnal polyuria in monosymptomatic nocturnal enuresis refractory to desmopressin treatment

The transition from day to night is associated with a pronounced decline in diuresis with reductions in the amount of excreted water, electrolytes, and other end products of our metabolism. Failure to do so leads to a large urine output at night, a condition known as nocturnal polyuria, encountered in a large proportion of children with nocturnal enuresis. The aim of this study was to clarify the mechanisms responsible for the nocturnal polyuria seen in enuretics with inadequate response to desmopressin (dDAVP). Forty-six enuretics (7-14 yr of age) and fifteen age-matched controls were admitted for a 24-h protocol with standardized fluid and sodium intake, comprising urine collections, blood sampling, and blood pressure monitoring. We included patients with severe enuresis (5 +/- 1 wet nights/wk) showing