Preliminary data indicate a high incidence of periodic limb movements in sleep at night in children with refractory nocturnal enuresis and increased cortical arousability, leading to awakening.

• Disturbance in the circadian rhythm of arginine vasopressin secretion is related to nocturnal polyuria in children with enuresis. • Desmopressin is recommended as a treatment for monosymptomatic nocturnal enuresis, working as a vasopressin analogue acting on V2 receptors in the collecting ducts of the kidney. What is New: • Other renal circadian rhythms might play a role in nocturnal polyuria, especially in desmopressin-resistant case.

Children with NE displayed higher sleep fragmentation and periodic limb movements in sleep than the control children with a possible sleep disorder without NE. The findings emphasise the central involvement of the pathophysiology of NE and the multifactorial nature of the condition.

We found that PLMS and cortical arousals in sleep were increased in children with monosymptomatic NE and polyuria, without a significant association with the enuretic parameters. These observations suggest the presence of a comorbid mechanism driven by a common, independent pacemaker. We hypothesize the autonomic system, its sympathetic branch, and the dopaminergic system as candidates for this pacemaker.

Patient motivation and compliance are generally stronger in clinical trials than in clinical practice. However, this study shows that some patients were poorly compliant with medication even at study initiation and only 71% were fully compliant with long-term treatment. Decreased compliance was associated with a lower response rate. Patients should be encouraged to comply fully with treatment to achieve an optimal outcome.