Incontinence Urine: Pediatric Enuresis

Introduction to Pediatric Enuresis for MCCQE1

For MCCQE1 preparation, understanding pediatric enuresis is crucial as it represents a common presentation in general pediatrics. Enuresis is defined as the repeated voiding of urine into clothes or bedclothes, whether involuntary or intentional.

To meet the diagnostic criteria (DSM-5), the behavior must occur:

• Twice a week for at least 3 consecutive months
• In a child who is at least 5 years of age (or equivalent developmental level)
• Not due to the direct physiological effect of a substance (e.g., diuretics) or a general medical condition (e.g., diabetes, spina bifida, seizure disorder).

Classification

Understanding the classification is vital for determining the appropriate workup and management strategy.

Etiology and Pathophysiology

Nocturnal enuresis is rarely psychological in origin (unless secondary). It is typically multifactorial.

1. Genetic Factors: Strong familial component. If both parents were enuretic, the risk is ~77%.
2. Nocturnal Polyuria: Reduced nocturnal secretion of Antidiuretic Hormone (ADH/Vasopressin).
3. Detrusor Overactivity: Reduced nocturnal bladder capacity.
4. Arousal Disorder: Inability to wake up in response to a full bladder.

Associated Conditions

• Constipation: A loaded rectum can compress the bladder (posteriorly) leading to instability. Always treat constipation first!
• Obstructive Sleep Apnea (OSA): Upper airway obstruction can lead to increased ANP (atrial natriuretic peptide) secretion and polyuria.

Clinical Evaluation for MCCQE1

Your goal is to rule out organic causes and classify the type of enuresis.

Differential Diagnosis

Management Strategies

Management should be tailored to the child and family’s motivation. Active treatment is generally not recommended before age 6.

1. Education and Supportive Measures (First-line)

• Reassurance: Explain the high rate of spontaneous resolution (15% per year).
• No Punishment: Crucial advice for parents. Punishment worsens the condition.
• Fluid Management: Restrict fluids 2 hours before bedtime; ensure adequate hydration during the day.
• Voiding Habits: Regular voiding during the day and “double voiding” before bed.
• Treat Constipation: Aggressive management of constipation often resolves enuresis.

2. Conditioning Alarm Therapy (Best Long-term Cure)

This is the most effective long-term treatment (highest cure rate, lowest relapse rate).

• Mechanism: Sensor detects moisture and sounds an alarm to wake the child.
• Duration: Requires 3-4 months of consistent use.
• Success Rate: ~66-70%.
• Indication: Motivated child and supportive family.

3. Pharmacotherapy (Desmopressin)

Used when rapid improvement is needed (e.g., sleepovers, camp) or if alarm therapy fails.

• Drug: Desmopressin (DDAVP) - synthetic analogue of ADH.
• Formulation: Oral melt (preferred) or tablet. Intranasal spray is contraindicated for enuresis due to risk of severe hyponatremia/seizures.
• Mechanism: Reduces nocturnal urine production.
• Relapse Rate: High upon discontinuation.
• Safety Warning: Fluid intake must be restricted 1 hour before and 8 hours after dosing to prevent water intoxication and hyponatremia.

4. Second-line Pharmacotherapy (Specialist Referral)

• Anticholinergics (e.g., Oxybutynin): Considered if there is evidence of reduced bladder capacity or overactive bladder (non-monosymptomatic). Usually combined with Desmopressin.
• Tricyclic Antidepressants (Imipramine): Rarely used now due to cardiotoxicity risk (fatal in overdose). Last resort.

Canadian Guidelines

The Canadian Paediatric Society (CPS) outlines specific recommendations relevant to Canadian practice:

• Screening: Evaluate for constipation in all children with enuresis.
• Referral: Refer to a pediatric urologist or nephrologist if:
  • Anatomic abnormalities are suspected.
  • Severe daytime symptoms present.
  • Recurrent UTIs.
  • Refractory to standard primary care management.

Key Points to Remember for MCCQE1

• Definition: Involuntary voiding > 2x/week for >3 months in a child ≥ 5 years old.
• Secondary Enuresis: Always investigate for organic causes (UTI, DM) or psychosocial stressors.
• First-line Investigation: Urinalysis (Rule out UTI, DKA, DI).
• First-line Treatment: Behavioral modification and enuresis alarm (highest cure rate).
• Pharmacotherapy: Desmopressin is effective for short-term dryness but has a high relapse rate.
• Safety: Never use intranasal desmopressin for enuresis; monitor for hyponatremia.

Sample Question

Clinical Scenario

A 7-year-old boy is brought to the clinic by his mother due to bedwetting. He wets the bed 3 to 4 nights per week. He has never been dry at night for more than a month. He denies any daytime incontinence, urgency, or dysuria. His bowel movements are regular and soft. He has no significant past medical history. His physical examination, including abdominal and neurological exam, is unremarkable. A urinalysis performed in the office is negative for glucose, protein, nitrites, and leukocytes. The mother is concerned because he wants to go to a sleepover camp in 2 weeks.

Question

Which one of the following is the most appropriate initial management for this patient’s specific goal?

• A. Reassurance and fluid restriction only
• B. Enuresis alarm therapy
• C. Oral desmopressin
• D. Referral to a pediatric urologist
• E. Imipramine

Explanation

The correct answer is:

• C. Oral desmopressin

Explanation: This patient has primary monosymptomatic nocturnal enuresis. While enuresis alarm therapy (Option B) is the most effective curative treatment with the lowest relapse rate, it requires 3-4 months to be effective. The clinical scenario highlights a specific short-term goal: attending a sleepover camp in 2 weeks.

• Option C (Oral desmopressin): This is the preferred choice for short-term dryness (e.g., sleepovers, camps) because it has an immediate effect. It reduces nocturnal urine production. The family must be counseled on fluid restriction to prevent hyponatremia.
• Option A (Reassurance): While important, it does not address the immediate concern of the camp and the social stigma/embarrassment the child wishes to avoid.
• Option B (Alarm therapy): This is the first-line treatment for long-term cure, but it takes too long to work for a camp starting in 2 weeks.
• Option D (Referral): Not indicated. This is an uncomplicated case of primary enuresis with a normal physical exam and urinalysis.
• Option E (Imipramine): Tricyclic antidepressants are third-line agents due to their side effect profile (cardiotoxicity) and are not appropriate as initial management.

References

1. Canadian Paediatric Society. (2020). Nocturnal enuresis in children and adolescents. Position Statement.
2. Kiddoo, D. (2012). Nocturnal Enuresis. Canadian Urological Association Journal.
3. UpToDate. Etiology and clinical features of bladder dysfunction in children.
4. Toronto Notes 2024. Pediatrics: Nephrology/Urology.
5. Medical Council of Canada. MCCQE Part I Objectives: Enuresis/Incontinence.