Enuresis: Possible causes
Behavioral interventions. Parents commonly try to stop their child’s bedwetting by restricting his or her fluid or caffeine intake, enforcing a reward system, bladder control training, and/or awakening the child overnight to go to the bathroom.Genetics. In more than one-half of children with enuresis, one or both parents had the disorder during childhood.
Developmental delay. Delayed functional CNS maturation can decrease arousal. Enuresis is common in children with developmental disorders, including autism, Rett’s syndrome, or pervasive developmental disorder NOS.
Irregular sleep pattern associated with specific sleep disorders, such as narcolepsy and sleep apnea. Also, children with enuresis sleep more soundly than do youths without the disorder.
Psychological problem. Considered a reaction to primary enuresis rather than its cause.
Medical condition. Enlarged adenoids, tonsils, constipation with fecal impaction, vertebral and spinal cord anomaly, and diabetes mellitus may cause enuresis.
Source: Reference 1
Among behavioral treatments, only the bedwetting alarm has shown effectiveness in clinical trials,1,3 and it carries the lowest risk of post-treatment relapse.3 Urine moistens a sensor in the bed pad or inside cloth, triggering an alarm that awakens the child when wetting starts. The child gradually awakens earlier in an enuretic episode until the sensation of bladder fullness awakens him.
Many parents/guardians and their children—particularly older youths—consider alarm systems demeaning. We again suggested this treatment to Jimmy and his parents, but they refused.
Medication. Six months of low-dose imipramine, a tricyclic antidepressant often prescribed for enuresis, produced no response. We did not restart imipramine at a higher dosage because of its association with increased arrhythmia risk.
We instead considered desmopressin acetate, a synthetic analog of ADH vasopressin that regulates diurnal variation, which is usually abnormal in children with enuresis. Desmopressin, often used to treat clozapine-induced enuresis in adults, has been associated with successful outcomes in as many as 65% of children in clinical trials.1,4
Desmopressin, however, can reduce urine production. Water intoxication or hyponatremia is rare but can lead to seizures or coma, and the risk increases with the dosage. Obtain informed consent from the parents before starting this drug. Check electrolytes 2 or 3 days after the first dose, 1 month later, then again every 2 to 3 months. Discontinue at once if serum sodium decreases significantly from baseline or is
Treatment: Meaningless response
We start Jimmy on oral desmopressin, 0.2 mg at bedtime, after discussing its benefits and risks with his parents. We increase the dosage to 0.4 mg after 3 days and to 0.6 mg the following week, as the lower dosages have not worked. Serum electrolytes, gauged before starting desmopressin and again 2 weeks later, are normal. We see Jimmy every 2 weeks to check progress and monitor for side effects.
Soon after the second dosage increase, Jimmy’s accidents gradually decrease to 2 to 3 per week, but no improvement is seen after that.
Two months later, Jimmy is still avoiding sleepovers and has trouble making friends. His parents worry about his increasing frustration, hopelessness, and low self-esteem. We again offer supportive counseling, but the boy refuses.
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The authors’ observations
We were running out of treatment options. Two medication trials failed, and the family still would not try a bedwetting alarm.
Urodynamic testing usually is not ordered unless the child has a history of urge incontinence or UTI. For some treatment-resistant patients, the test can reveal detruser muscle or bladder capacity deficits that might be causing enuresis.
Testing: Below the norm
We refer Jimmy to a urologist for a urodynamic test. Results showed mild detruser muscle instability and slightly low maximum bladder capacity compared with age-predicted norms.
The authors’ observations
Based on this finding, we considered oxybutynin, an anticholinergic agent that increases bladder control by relaxing the smooth muscles. Patients with detruser instability and inadequate bladder capacity have responded well to oxybutynin in clinical trials,5,6 and combination oxybutynin/desmopressin therapy has been shown effective in treatment-resistant patients.7-9
Oxybutynin and desmopressin complement each other; reduced urinary output and bladder filling associated with desmopressin can reduce uninhibited bladder contractions, thus enhancing oxybutynin’s action.
Treatment: Happy summer
We continue desmopressin, 0.6 mg nightly, and add extended-release oxybutynin, 2.5 mg/d. We increase oxybutynin to 5 mg/d after 3 days and to 10 mg/d the following week, as Jimmy reported no side effects from the lower dosages.
We see Jimmy 1 week after adding oxybutynin, then again 3 weeks later. He reports no wet nights after 1 month of combination therapy, then wets his bed once over the next 2 months. We continue to see him every 3 to 4 weeks and check his electrolytes every 2 to 3 months. He reports no side effects