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 Urinary Incontinence in Children: A Merck Manual of Patient Symptoms podcast
Urinary incontinence is defined as involuntary voiding of urine ≥ 2 times/mo during the day or night. Daytime incontinence (diurnal enuresis) is usually not diagnosed until age 5 or 6. Nighttime incontinence (nocturnal enuresis, or bed-wetting) is usually not diagnosed until age 7. Before this time, nocturnal enuresis is typically referred to as nighttime wetting. These age limits are based on children who are developing typically and so may not be applicable to children with developmental delay. Both nocturnal and diurnal enuresis are symptoms—not diagnoses—and necessitate consideration of an underlying cause.
The age at which children attain urinary continence varies, but > 90% are continent during the day by age 5. Nighttime continence takes longer to achieve. Nocturnal enuresis affects about 30% of children at age 4, 10% at age 7, 3% at age 12, and 1% at age 18. About 0.5% of adults continue to have nocturnal wetting episodes. Nocturnal enuresis is more common among boys and when there is a family history.
In primary enuresis, children have never achieved urinary continence for ≥ 6 mo. In secondary enuresis, children have developed incontinence after a period of at least 6 mo of urinary control. An organic cause is more likely in secondary enuresis. Even when there is no organic cause, appropriate treatment and parental education are essential because of the physical and psychologic impact of urine accidents.
Pathophysiology
Bladder function has a storage phase and a voiding phase. Abnormalities in either phase can cause primary or secondary enuresis.
In the storage phase, the bladder acts as a reservoir for urine. Storage capacity is affected by bladder size and compliance. Storage capacity increases as children grow. Compliance can be decreased by repeated infections or by outlet obstruction, with resulting bladder muscle hypertrophy.
In the voiding phase, bladder contraction synchronizes with the opening of the bladder neck and the external urinary sphincter. If there is dysfunction in the coordination or sequence of voiding, enuresis can occur. There are multiple reasons for dysfunction. One example is bladder irritation, which can lead to irregular contractions of the bladder and asynchrony of the voiding sequence, resulting in enuresis. Bladder irritation can result from a UTI or from anything that presses on the bladder (eg, a dilated rectum caused by constipation).
Etiology
Urinary incontinence in children has different causes and treatments than urinary incontinence in adults. Although some abnormalities cause both nocturnal and diurnal enuresis, etiology can vary depending on whether enuresis is nocturnal or diurnal, as well as primary or secondary. Most primary enuresis is nocturnal and not due to an organic disorder. Nocturnal enuresis can be divided into monosymptomatic (occurring only during sleep) and complex (other abnormalities are present, such as urgency or diurnal enuresis).
Nocturnal enuresis:
Organic disorders account for about 30% of cases and are more common in complex compared to monosymptomatic enuresis. The remaining majority are of unclear etiology but are thought to be due to a combination of factors, including
The factors contributing to organic causes of nocturnal enuresis include
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Table 1
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| Some Factors Contributing to Nocturnal Enuresis |
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Cause
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Suggestive Findings
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Diagnostic Approach
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Constipation
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Infrequent, hard-pebble stools
Encopresis
Abdominal discomfort
History of constipating diet (eg, excessive milk and dairy, few fruits and vegetables)
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Clinical evaluation
Sometimes abdominal x-ray
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Increased urine output due to any cause (eg, diabetes mellitus, diabetes insipidus, excessive water intake, sickle cell disease or trait)
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Vary by disorder
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For diabetes mellitus, serum glucose
For diabetes insipidus, serum and blood osmolality
For sickle cell, sickle cell screen
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Maturational delay
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No diurnal enuresis
More common among boys and heavy sleepers
Possible family history of bed-wetting
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Clinical evaluation
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Sleep apnea
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History of snoring with sounds of breathing pauses followed by loud snorts
Excessive daytime sleepiness
Enlarged tonsils
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Polysomnography
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Spinal dysraphism (eg, spina bifida, tethered cord, occult defects), leading to urinary retention
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Obvious vertebral defects, protruding meningeal sac, lumbosacral dimple or hair tuft, lower-extremity weakness, decreased sensation in lower extremities
Absence of ankle jerk reflex, cremasteric reflex, and anal wink
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Lumbosacral x-rays
For occult conditions, spinal MRI
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Stress
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School difficulties, social isolation or difficulties, family stress (eg, divorce, separation)
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Clinical evaluation
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UTI
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Dysuria, hematuria, frequency, urgency
Fever
Abdominal pain
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Urinalysis
Urine culture
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Diurnal enuresis:
Common causes include
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Table 2
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| Some Organic Causes of Diurnal Enuresis |
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Cause
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Suggestive Findings
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Diagnostic Approach
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Constipation
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Infrequent, hard-pebble stools
Sometimes encopresis, abdominal discomfort
History of constipating diet (eg, excessive milk and dairy, few fruits and vegetables)
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Clinical evaluation
Sometimes abdominal x-ray
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Dysfunctional voiding secondary to lack of coordination of the detrusor muscle and uretheral sphincter and not related to a neurologic cause
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Children also more likely to have encopresis, VUR, and UTI
Possibly nocturnal and diurnal enuresis
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Urodynamic studies to show dyssynergy of bladder musculature
Sometimes VCUG
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Giggle incontinence
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Voiding during laughing, almost exclusively in girls
At other times, completely normal voiding
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Clinical evaluation
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Increased urine output due to any cause (eg, diabetes mellitus, diabetes insipidus, excessive water intake, sickle cell disease or trait)
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Vary by disorder
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For diabetes mellitus, urinalysis for glucose and ketones*
For diabetes insipidus, serum and blood osmolality
For sickle cell, sickle cell screen
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Micturation deferral with overflow incontinence
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In children, waiting to the last minute to void
Common among preschool children when absorbed in play activities
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Consistent history
Voiding diary
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Neurogenic bladder secondary to spinal dysraphism (eg, spina bifida, tethered cord, occult defects) or nervous system defect
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Obvious vertebral defects, protruding meningeal sac, lumbosacral dimple or hair tuft, lower-extremity weakness, decreased sensation in lower extremities
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Lumbosacral x-rays
For occult conditions, spinal MRI
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Overactive bladder
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Urinary urgency (essential for diagnosis); frequency and nocturia also common
Sometimes children engage in holding maneuvers (eg, squatting or Vincent curtsy sign)
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History consistent with symptoms or overactive bladder
Urodynamic studies considered
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Sexual abuse
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Sleep problems, school problems (eg, delinquency, poor grades)
Seductive behavior, depression, unusual interest in or avoidance of all things sexual, inappropriate knowledge of sexual things for age
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Evaluation by sexual abuse experts
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Stress†
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School difficulties, social isolation or difficulties, family stress (eg, divorce, separation)
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Clinical evaluation
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Structural abnormality (eg, ectopic ureter or posterior urethral valves)
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In children, full diurnal continence never achieved
Diurnal and nocturnal enuresis in girls, history of normal voiding but with continually wet underwear, vaginal discharge
Possible history of UTIs, history of other urinary tract abnormalities
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Renal flow scan or IV urography
CT of abdomen and pelvis
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UTI
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Dysuria, hematuria, frequency, urgency
Fever
Abdominal pain
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Urinalysis
Urine culture
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Vaginal reflux (urethrovaginal reflux or vaginal voiding) due to any cause (including labial adhesions)
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Dribbling when standing after urination
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Clinical evaluation, including improvement with instruction on proper method of voiding to discourage retention of urine in vagina (eg, sitting backward on toilet or with knees wide apart)
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*Diabetes does not typically cause nocturnal enuresis until after glucose enters the urine.
†Stress is a cause primarily when incontinence is acute.
VCUG = voiding cystourethrogram; VUR = vesicoureteral reflux.
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Evaluation
Evaluation should always include assessment for constipation (which can be a contributing factor to both nocturnal and diurnal enuresis).
History:
History of present illness inquires about onset of symptoms (ie, primary vs secondary), timing of symptoms (eg, at night, during the day, only after voiding), and whether symptoms are continuous (ie, constant dribbling) or intermittent. Recording a voiding schedule, including timing, frequency, and volume of voids, can be helpful. Important associated symptoms include polydipsia, dysuria, urgency, frequency, dribbling, and straining. Position during voiding and strength of urine steam should be noted. To prevent leakage, children with enuresis may cross their legs or use other postures, which increase their risk of UTIs.
Review of systems should seek symptoms suggesting a cause, including frequency and consistency of stools (constipation); fever, abdominal pain, dysuria, and hematuria (UTI); perianal itching and vaginitis (pinworm infection); polyuria and polydipsia (diabetes insipidus or diabetes mellitus); and snoring or breathing pauses during sleep (sleep apnea). Children should be screened for the possibility of sexual abuse, which, although an uncommon cause, is too important to miss.
Past medical history should identify known possible causes, including perinatal insults or birth defects (eg, spina bifida), neurologic disorders, renal disorders, and history of UTIs. Any current or previous treatments for enuresis and how they were actually instituted should be noted, as well as a list of current drugs.
Developmental history should note developmental delay or other developmental disorders related to voiding dysfunction (eg, attention-deficit/hyperactivity disorder, which increases the likelihood of enuresis).
Family history should note the presence of nocturnal enuresis and any urologic disorders.
Social history should note any stressors occurring near the onset of symptoms, including difficulties at school, with friends, or at home; although enuresis is not a psychologic disorder, a brief period of wetting may occur during stress.
Clinicians also should ask about the impact of enuresis on the child because it also affects treatment decisions.
Physical examination:
Examination begins with review of vital signs for fever (UTI), signs of weight loss (diabetes), and hypertension (renal disorder). Examination of the head and neck should note enlarged tonsils, mouth breathing, or poor growth (sleep apnea). Abdominal examination should note any masses consistent with stool or a full bladder.
In girls, genital examination should note any labial adhesions, scarring, or lesions suspicious of sexual abuse. An ectopic ureteral orifice is often difficult to see but should be sought. In boys, examination should check for meatal irritation or any lesions on the glans or around the rectum. In either sex, perianal excoriations can suggest pinworms.
The spine should be examined for any midline defects (eg, deep sacral dimple, sacral hair patch). A complete neurologic evaluation is essential and should specifically target lower-extremity strength, sensation and deep tendon reflexes, sacral reflexes (eg, anal wink), and, in boys, cremasteric reflex to identify possible spinal dysraphism. A rectal examination may be useful to detect constipation or decreased rectal tone.
Red flags:
Findings of particular concern are
Interpretation of findings:
Usually, primary nocturnal enuresis occurs in children with an otherwise unremarkable history and examination and probably represents maturational delay. A small percentage of children have a treatable medical disorder; sometimes findings suggest possible causes (see Table 1: Incontinence in Children: Some Factors Contributing to Nocturnal Enuresis ).
In diurnal enuresis, dysfunctional voiding is suggested by intermittent enuresis preceded by a sense of urgency, a history of being distracted by play, or a combination. Enuresis after urination (due to lack of total bladder emptying) can also be part of the history.
Enuresis caused by a UTI is likely a discrete episode rather than a chronic, intermittent problem and may be accompanied by typical symptoms (eg, urgency, frequency, pain on urination); however, other causes of enuresis can result in secondary UTI.
Constipation should be considered in the absence of other findings in children who have hard stools and difficulty with elimination (and sometimes palpable stool on examination).
Sleep apnea should be considered with a history of excessive daytime sleepiness and disrupted sleep. Rectal itching (especially at night), vaginitis, urethritis, or a combination can be an indication of pinworms. Excessive thirst, diurnal and nocturnal enuresis, and weight loss suggest a possible organic cause (eg, diabetes mellitus). Stress or sexual abuse can be difficult to ascertain but should be considered.
Testing:
Diagnosis is often apparent after history and physical examination. Urinalysis is appropriate for both sexes, often with addition of urine culture for girls. Further testing is useful mainly when history, physical examination, or both suggest an organic cause (see Table 1: Incontinence in Children: Some Factors Contributing to Nocturnal Enuresis and Table 2: Incontinence in Children: Some Organic Causes of Diurnal Enuresis).
Treatment
The most important part of treatment is family education about the cause and clinical course of enuresis. Education helps decrease the negative psychologic impact of urine accidents and results in increased adherence with treatment.
Treatment should be targeted toward any cause that is identified; however, frequently no cause is found. In such cases, the following treatments may be useful.
Nocturnal enuresis:
The most effective long-term strategy is a bed-wetting alarm. Although labor intensive, the success rate can be as high as 70% when children are motivated to end the enuresis, and the family is able to adhere. It can take up to 4 mo of nightly use for complete resolution of symptoms. It is essential to avoid punitive approaches because these undermine treatment and lead only to poor self-esteem.
Drugs such as desmopressin (DDAVP) and imipramine (see Table 3: Incontinence in Children: Drugs Used for Enuresis in Children*) can decrease nighttime wetting episodes; however, results are not sustained in most patients when the treatment is stopped. DDAVP is preferable to imipramine because of the rare potential of sudden death with imipramine use.
Diurnal enuresis:
It is important to treat any underlying constipation. Information from the voiding diary can help identify opportunities for intervention. General measures may include
For labial adhesions, a conjugated estrogen cream may also be used.
Drug treatment (see Table 3: Incontinence in Children: Drugs Used for Enuresis in Children*) is sometimes helpful but is not typically first-line therapy. Anticholinergic drugs may benefit patients with diurnal enuresis due to voiding dysfunction when behavioral therapy or physiotherapy is unsuccessful. Drugs for nocturnal enuresis may be useful in decreasing nighttime wetting episodes and are sometimes useful to encourage dryness during overnight events such as sleepovers.
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Table 3
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| Drugs Used for Enuresis in Children* |
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Drug
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Dosage
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Some Adverse Effects
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Voiding dysfunction in diurnal enuresis (bladder overactivity)
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Oxybutynin
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Children > 5 yr: 5 mg po bid, may be increased to 5 mg tid
Extended release > 6 yr: 5 mg/day, increased as tolerated by 5 mg/day to a maximum dose of 20 mg/day
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Confusion, dizziness, increased temperature, flushing
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Nocturnal enuresis
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Desmopressin (DDAVP)
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In children ≥ 6 yr, initially 0.2 mg po once/day 1 h before bedtime, increased prn to a maximum of 0.6 mg once/day
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Intranasal DDAVP is no longer recommended because of the risk of dilutional hyponatremia
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Imipramine
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25 mg po once/day at night (children 6–8 yr)
50 mg po once/day at night (children > 8 yr)
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Rarely, death†
Possible nervousness, personality change, and disordered sleep
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*These drugs are mostly used as 2nd-line therapy. Treatment of the underlying disorder and behavioral therapy should be used first.
†There have been reports of sudden death of unclear etiology. This drug is now rarely used.
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Key Points
Last full review/revision August 2009 by Leonard Rappaport, MD, MS; Laura Weissman, MD
Content last modified August 2009
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