Enuresis

CHAPTER 12 Enuresis

Hyeyoung Lee, MD, MS and
Sang Won Han, MD, PhD

A normal 7-year-old boy suddenly develops daytime urinary frequency every 20 minutes without incontinence. His symptom is limited to daytime only, and no enuresis was reported. Medicosurgical history, physical examination, urinalysis, and brief ultrasound of the kidneys and bladder are normal. What is the most appropriate management option?

The daytime urinary frequency is a benign, yet extremely common condition, which occurs in otherwise normal children who have no associated daytime incontinence or nighttime symptoms. The etiology is generally unknown and a conservative approach is not unreasonable. Symptoms quite often occur in association with psychological stress or environmental changes. It usually resolves in 2 to 4 months and is characteristically unaffected by anticholinergic drugs. However, urinalysis should be performed for the differential diagnosis of symptomatic cystitis.

An otherwise normal 6-year-old boy wets his bed 2 or 3 times a week at night. He has no urinary symptoms during the daytime. What is the most likely cause of his nocturnal enuresis?

Primary nocturnal enuresis can be multifactorial but is commonly explained to occur from nocturnal urine output that is in excess of the bladder reservoir capacity during sleep at night. Nocturnal polyuria, whether it is absolute in association with deranged antidiuretic hormone secretion or relative due to reduced functional bladder capacity during sleep, results in a mismatch between urine production and nocturnal bladder capacity. Decreased arousal to the sense of bladder fullness during sleep is also considered as one of the causes.

Urinary overproduction in enuretic children would be due to what?

• Abnormal circadian secretion of vasopressin.

• Increased natriuretic factor secretion.

• Increased dietary sodium.

• Defect in renal aquaporin-2 receptors in the kidney.

What percentage of nocturnal enuresis patients have a significantly smaller functional bladder capacity than age-matched normal children?

Approximately 20%. Functional capacity meaning that the bladder is not anatomically small, but tends to contract before it is full.

What percentage of nocturnal enuresis patients have a problem with arousal from sleep?

Approximately one-third. Enuretic children are universally regarded as deep-sleepers who do not wake up in response to bladder distension or detrusor contractions which are strong arousal stimuli. This high arousal threshold may have brainstem explanations or may be caused by chronic arousal stimuli itself.

True/False: Treatment of nocturnal enuresis with overactive bladder with an anticholinergic is no better than placebo.

True. But adding an anticholinergic to other remedies in difficult cases may be helpful. A buzzer alarm alone will cure approximately two-thirds.

A 7-year-old boy has been taking imipramine for 3 months due to enuresis. What is the most potent pharmacologic effect of imipramine on the lower urinary tract?

The antienuretic mechanism of tricyclic antidepressant imipramine is not absolutely clear, but it is most likely linked to noradrenergic action in the brainstem. Its actions in the urinary tract are direct inhibition of bladder smooth muscle, and analgesic effect. Imipramine is only considered in severely therapy-resistant individuals due to the relatively high rate of side effects and the potential for overdose.

True/False: A 4-year-old boy with nighttime bed wetting should be actively evaluated and treated for enuresis.

False. The diagnosis of enuresis can only be made after 5 years of age.

A 6-year-old girl has been suffering from marked urinary frequency and urgency for 2 weeks. Physical examination is normal, and her urinalysis and culture are normal. The next step should be?

Observation. In the case of a pediatric benign condition, evaluation should be minimal if no significant complication is eminent. In most cases, spontaneous improvement is the rule.

The mother of a 5-year-old boy who still wets his bed at night was concerned about the chance of recovery by the age of 15. What is the percent of recovery you can tell this mother?

Ninety-nine percent.

The parents of a 6-year-old girl who still wets her bed at night tell the pediatrician that her older brother was also an enuretic. What percentage of children at age 5 are enuretic?

Approximately 15% of normal children will still wet at night at 5 years of age. Enuresis is defined as an involuntary discharge of urine. The term is often used alone, imprecisely, to describe wetting that occurs only at night during sleep. It is more accurate, however, to refer to nighttime wetting as nocturnal enuresis and to distinguish it from daytime wetting or diurnal enuresis. The age at which enuresis becomes inappropriate depends on the statistics of developing urinary control, the pattern of wetting, and the sex of the child. Nocturnal enuresis occurring after the age of 5 or by the time the child enters grade school is generally considered a cause for concern.

What is the spontaneous resolution rate for nocturnal enuresis without treatment?

The spontaneous resolution rate is approximately 15% per year.

Parents of an infant boy are curious about enuresis, since both of the parents were enuretic themselves. What percentage of patients with nocturnal enuresis have a positive family history for the same condition?