A 6-year-old boy is brought to the office by his mother due to bed-wetting. The patient has stayed dry during the daytime since age 3 but has continued to wet his bed at night. At the last visit 2 months ago, the mother noted that he was wetting the bed once or twice a week. Behavioral modifications were recommended at that time, with improvement in frequency of symptoms. However, since kindergarten started a month ago, frequent nighttime bed-wetting has recurred. In the last week, the mother has also noticed that liquid stool has frequently leaked onto the underwear. The patient's height and weight track along the 50th percentile. Vital signs are normal. On physical examination, the left side of the abdomen is firmer compared to the right. Rectal sphincter tone is normal. Genitalia are normal. Gait is normal. Which of the following is the best next step in management of this patient?
Primary nocturnal enuresis | |
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Pathogenesis |
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Evaluation |
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Management |
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ADH = antidiuretic hormone. | |
Nocturnal enuresis refers to nighttime urinary incontinence (ie, bed-wetting) in children age ≥5. Enuresis is particularly common in young boys and is typically an isolated condition that self-resolves in early childhood. However, an underlying cause should be suspected in a child with new or worsening symptoms, as seen in this patient.
Constipation is commonly associated with bladder dysfunction and should be considered in any patient with enuresis. Because of the close proximity of the bladder to the rectum, fecal retention can lead to a decreased functional bladder capacity and instability of the detrusor muscle of the bladder. Although often mistaken as diarrhea, encopresis (ie, fecal incontinence) is usually a sign of constipation and is characterized by leakage around impacted stool. Symptoms are often preceded by social changes (eg, new school, family discord) that lead to stool-withholding behaviors in previously toilet-trained children. Left-sided firmness (as seen in this patient), or a palpable fecal mass, on abdominal examination further supports the diagnosis of constipation.
The first step in management of enuresis involves treatment of any comorbid conditions. In patients with encopresis, laxative therapy (eg, polyethylene glycol) often resolves both constipation and enuresis. If urinary incontinence persists after successful treatment of bowel dysfunction, other therapies for primary enuresis (eg, bed-wetting alarm, desmopressin) may be considered (Choice C).
(Choice B) Lumbosacral MRI can be used to evaluate for a spinal abnormality (eg, spina bifida) causing bowel and bladder incontinence. However, daytime symptoms would also be present. In addition, examination findings can include decreased rectal sphincter tone and abnormal gait (eg, leg weakness), neither of which is seen here.
(Choice D) Imaging with renal ultrasound and voiding cystourethrography can be used to assess for an anatomic anomaly such as posterior urethral valves. Patients typically have other urinary findings (eg, daytime incontinence, weak stream, frequent urinary infections) in addition to enuresis, and encopresis would not be expected.
(Choice E) Although fluids should be minimized before bedtime in patients with nocturnal enuresis, daytime fluid restriction is not recommended because it can further exacerbate constipation and lead to dehydration.
Educational objective:
Encopresis (ie, fecal incontinence) is typically a sign of stool impaction, which can cause or worsen nocturnal enuresis. Resolution of enuresis is often achieved by successfully managing comorbid constipation (eg, laxative therapy).