Treatment for Nighttime Bed Wetting Related to ADH Deficiency
Desmopressin is the first-line pharmacological treatment for nocturnal enuresis caused by antidiuretic hormone deficiency, particularly in children with nocturnal polyuria. 1
Pathophysiology and Diagnosis
Nocturnal enuresis related to hormonal imbalances is often caused by insufficient antidiuretic hormone (ADH/vasopressin) secretion during sleep, leading to:
- Nocturnal polyuria (urine production greater than 130% of expected bladder capacity)
- Inability to concentrate urine at night
- Excessive nighttime urine production
Before initiating treatment, it's essential to determine if the patient has:
- Monosymptomatic nocturnal enuresis (MNE) - bedwetting without other lower urinary tract symptoms
- Nonmonosymptomatic nocturnal enuresis (NMNE) - bedwetting with daytime symptoms
A frequency-volume chart should be completed for at least 2 days to measure fluid intake and voided volume, with documentation of enuresis episodes for at least 1 week 1. Weighing diapers can help assess nocturnal urine production.
Treatment Algorithm
First-Line Treatment for ADH Deficiency
- Desmopressin (Grade Ia evidence) 1
- Synthetic vasopressin analog that decreases urine production at night
- Most effective in patients with:
- Nocturnal polyuria
- Normal bladder capacity (maximum voided volume >70% of expected for age)
- Dosing: Oral tablets (0.2-0.6 mg nightly)
- Response rates: 30% full response, 40% partial response 1
Safety Considerations with Desmopressin
- Fluid restriction is mandatory - limit evening fluid intake to 200 ml (6 ounces) or less after medication and no drinking until morning 1, 2
- Monitor for hyponatremia, which can cause seizures, coma, or death 2
- Contraindicated in patients with:
- Moderate to severe renal impairment
- History of hyponatremia
- Polydipsia
- Heart failure or uncontrolled hypertension 2
Alternative Treatment Options
If desmopressin fails or is contraindicated:
Enuresis Alarm (Grade Ia evidence) 1
Tricyclic Antidepressants (e.g., imipramine) 1
- Consider only if other treatments fail
- Dosage: 1.0-2.5 mg/kg at bedtime
- Effectiveness: 40-60% with high relapse rate (50%)
- Caution: Obtain ECG before treatment due to cardiac arrhythmia risk
General Lifestyle Recommendations
In addition to pharmacological treatment:
- Regular voiding schedule during the day (morning, at least twice during school, after school, dinner time, bedtime) 1
- Minimize evening fluid and solute intake 1
- Encourage liberal water intake during morning and early afternoon 1
- Treat constipation if present 1
- Maintain a calendar of dry and wet nights 1
- Provide emotional support and avoid punishment for bedwetting 1
Monitoring and Follow-Up
- For desmopressin: Monitor serum sodium within 1 week and approximately 1 month after starting treatment 2
- Continue treatment for at least 3-6 months before attempting to discontinue
- Assess for relapse after treatment withdrawal
Common Pitfalls to Avoid
- Inadequate fluid restriction with desmopressin - can lead to water intoxication and hyponatremia 2
- Premature discontinuation of treatment - leads to high relapse rates
- Ignoring comorbid conditions - constipation and neuropsychiatric disorders like ADHD can decrease treatment success 1
- Punitive approaches - can worsen psychological impact and treatment adherence 1
- Focusing only on medication - behavioral strategies are equally important
Special Considerations
Recent research suggests that desmopressin may be effective even in patients with concentrated morning urine (≥800 mOsm/L), challenging the traditional view that it should only be used in those with dilute urine 5. However, the International Children's Continence Society guidelines still recommend it primarily for those with nocturnal polyuria 1.
Remember that enuresis tends to resolve spontaneously in many children as they grow, but treatment is justified due to the significant psychological impact of the condition 1.