Diurnal Enuresis in Children
Diurnal enuresis, or daytime wetting, is the involuntary passage of urine in a child over the age of five years who is otherwise continent at night. It is a common condition that can cause significant distress and social difficulties. The management of diurnal enuresis is based on a thorough assessment to identify the underlying cause and a stepped approach to treatment.
Classification and Causes
Diurnal enuresis is often a symptom of an underlying bladder or bowel dysfunction.
Overactive Bladder (OAB): This is the most common cause. The bladder contracts involuntarily, leading to a sudden and strong urge to urinate, which the child cannot suppress. This is often associated with a reduced functional bladder capacity and frequent urination.
Dysfunctional Voiding: The child has a habit of contracting their pelvic floor muscles instead of relaxing them during urination. This leads to an incomplete emptying of the bladder and can cause dribbling or a weak urinary stream.
Giggle Incontinence: A rare form where the child voids their entire bladder during a fit of laughter.
Underactive Bladder: The child has a weak bladder muscle and struggles to empty their bladder completely.
Constipation: A common cause of both nocturnal and diurnal enuresis. A full rectum can press on the bladder and reduce its capacity.
Clinical Assessment
A detailed history is the most important part of the assessment.
Fluid Intake: Ask about the quantity and type of fluids the child drinks, and if they avoid drinking to prevent wetting.
Voiding Diary: Ask the family to keep a bladder diary for 48 hours. This should include the time and amount of each urination, as well as the time and amount of fluid intake. It is an invaluable tool for diagnosing bladder dysfunction.
Voiding Symptoms: Enquire about:
Frequency: How often the child urinates.
Urgency: Whether the child has a sudden and uncontrollable urge to urinate.
Straining or Weak Stream: Signs of dysfunctional voiding.
Daytime Wetting: The frequency and severity of wetting episodes.
Associated Symptoms: Ask about signs of constipation and any psychosocial issues, such as anxiety or bullying.
Examination and Investigations
Physical Examination: A full abdominal and neurological examination of the lower limbs and spine should be performed to rule out a structural or neurological cause.
Urinalysis: A urinalysis should be performed to rule out a urinary tract infection.
Bladder Diary: This is the most useful investigation. It can provide a clear picture of the child’s bladder function and help to differentiate between different types of bladder dysfunction.
Imaging: In some cases, a bladder ultrasound may be considered to assess for residual urine after voiding.
Management
Management is a stepped approach based on the underlying cause.
Behavioural and Lifestyle Modifications: This is the first-line treatment for all children.
Fluid Advice: Encourage adequate fluid intake, but avoid fizzy and caffeinated drinks.
Timed Voiding: Create a schedule for the child to use the toilet every 2-3 hours, regardless of whether they feel the urge to go.
Good Voiding Posture: Ensure the child sits on the toilet with their feet flat on the floor or on a stool to relax the pelvic floor muscles.
Constipation: Address any constipation with dietary changes and, if necessary, laxatives.
Pharmacological Management: Medications are considered for children with overactive bladder or other specific bladder dysfunctions that have not responded to behavioural therapy.
Oxybutynin: This is an anticholinergic drug that works by relaxing the bladder muscle and reducing involuntary contractions. It is commonly used for overactive bladder.
Tolterodine: This is another anticholinergic drug with similar effects to oxybutynin but may have fewer side effects.
Desmopressin: Although primarily used for nocturnal enuresis, it may be used in combination with other medications if nocturnal polyuria is also present.