Enuresis

Specialty: Nephrology and urology.

• nocturnal enuresis
• involuntary loss of urine during sleep

Why it occurs

• Maturational delay in the control of nocturnal urination (idiopathic, with a strong hereditary component in childhood)
• Nocturnal deficiency of antidiuretic hormone (failure in the physiological increase of vasopressin during sleep, resulting in nocturnal polyuria)
• Obstructive sleep apnea syndrome (causes nocturnal hypoxia with release of atrial natriuretic peptide, increasing urine production and inhibiting awakening)
• Diabetes mellitus or diabetes insipidus of debut (osmotic polyuria or due to lack of ADH exceeds the nocturnal retention capacity)
• Overactive bladder or detrusor instability during sleep
• Psychological stressors or emotional regression (secondary enuresis)

Initial workup

Detailed voiding diary (recording volume and time of water intake, volume of daytime urine output, and frequency of nocturnal wet episodes); physical-chemical analysis of urine to determine urinary density, presence of glucose, ketones and infection; renal and bladder ultrasound with determination of post-void residual; polysomnography study if associated with snoring and witnessed apneas.

Standard management

• Desmopressin — 0.1-0.4 mg orally or sublingual lyophilized at bedtime; synthetic analogue of ADH that reduces nocturnal urine production. It is critical to strictly restrict fluid intake from 1 hour before to 8 hours after drinking to avoid severe dilutional hyponatremia.
• Oxybutynin — 5 mg orally before sleeping, useful anticholinergic if nocturnal detrusor hyperactivity coexists
• Nocturnal enuresis alarms (first-line behavioral therapy with humidity sensing device).