Urinary Incontinence In Children
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 (1).
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 (2).
1. Horowitz M, Misseri R: Diurnal and nocturnal enuresis. In Clinical Pediatric Urology, ed. 5, edited by Docimo S, Canning D, Khoury A. London, Martin Dunitz Ltd., 2007, pp. 819–840.
2. Austin PF, Vricella GJ: Functional disorders of the lower urinary tract in children. In Campbell-Walsh Urology, ed. 11, edited by Wein A, Kavoussi L, Partin A, Peters C. Philadelphia, Elsevier, 2016, pp. 3297–3316.
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).
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 diurnal enuresis and/or urinary symptoms).
Organic disorders account for about 30% of cases and are more common in complex compared to monosymptomatic enuresis. The remaining majority of cases are of unclear etiology but are thought to be due to a combination of factors, including
Uncompleted toilet training
Functionally small bladder capacity (the bladder is not actually small but contracts before it is completely full)
Increased nighttime urine volume
Difficulties in arousal from sleep
Family history (if one parent had nocturnal enuresis, there is a 30% chance offspring will have it, increasing to 70% if both parents were affected)
The factors contributing to organic causes of nocturnal enuresis include
Some Factors Contributing to Nocturnal Enuresis
Common causes include
Relative weakness of the detrusor muscle (making it difficult to inhibit incontinence)
Constipation, urethrovaginal reflux, or vaginal voiding: girls who use an incorrect position during voiding (eg, with legs close together) or have redundant skinfolds may have reflux of urine into the vagina, which subsequently leaks out on standing
Structural abnormalities (eg, ectopic ureter)
Abnormal sphincter weakness (eg, spina bifida, tethered cord)
Some Organic Causes of Diurnal Enuresis
Evaluation should always include assessment for constipation (which can be a contributing factor to both nocturnal and diurnal enuresis).
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 (voiding diary), 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 use holding maneuvers, such as crossing their legs or squatting (sometimes with their hand or heel pushed against their perineum). In some children, holding maneuvers can increase their risk of UTIs. Similar to the voiding diary, a stooling diary can help identify constipation.
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.
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.
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: Some Factors Contributing to Nocturnal Enuresis).
For children who are being evaluated for nocturnal enuresis, it is important to determine whether diurnal symptoms of urgency, frequency, body posturing or holding maneuvers, and incontinence are present. Children with these symptoms have complex nocturnal enuresis, and management should be directed primarily toward controlling the diurnal symptoms.
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; parents may provide a history of snoring or respiratory pauses.
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.
Diagnosis is often apparent after history and physical examination. Urinalysis and urine culture are appropriate for both sexes. Further testing is useful mainly when history, physical examination, or both suggest an organic cause (see Table: Some Factors Contributing to Nocturnal Enuresis and see Table: Some Organic Causes of Diurnal Enuresis). Ultrasonography of the kidneys and bladder is often done to verify urinary tract anatomy is normal. Uroflow testing can show a staccato voiding pattern in patients with dysfunctional voiding.
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 of urinary incontinence should be targeted toward any cause that is identified; however, frequently no cause is found. In such cases, the following treatments may be useful.
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. The alarm triggers when wetting occurs. Although children initially continue to have wetting episodes, over time, they learn to associate the sensation of a full bladder with the alarm and then wake up to void prior to an enuretic event. These alarms are readily available online without prescription. An alarm should not be used by children with complex nocturnal enuresis or children with reduced bladder capacity (as evidenced by voiding diary). These children should be treated the same as children with diurnal enuresis. 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: Drugs Used for Enuresis in Children*) can decrease nighttime wetting episodes. However, results are not sustained in most patients when the treatment is stopped; parents and children should be forewarned of this to help limit disappointment. DDAVP is preferable to imipramine because of the rare potential of sudden death with imipramine use.
It is important to treat any underlying constipation. Information from the voiding diary can help identify children with reduced functional bladder capacity, frequency and urgency of urination, and urinary infrequency, all of whom may present with urinary incontinence.
General measures may include
Urgency containment exercises: Children are directed to go to the bathroom as soon as they feel the urge to urinate. They then hold the urine as long as they can and, when they can hold it no longer, start to urinate and then stop and start the urine stream. This exercise strengthens the sphincter and gives children confidence that they can make it to the bathroom before they have an accident.
Gradual lengthening of voiding intervals (if detrusor instability or dysfunctional voiding is suspected)
Changes in behaviors (eg, delayed urination) through positive reinforcement and scheduled urination (time voiding): Children are reminded to urinate by a clock that vibrates or sounds an alarm (preferable to having a parent in the reminder role).
Use of correct voiding methods to discourage retention of urine in the vagina: In girls experiencing vaginal pooling of urine, treatment is to encourage sitting facing backward on the toilet or with the knees wide apart, which will spread the introitus and allow direct flow of urine into the toilet.
For labial adhesions, a conjugated estrogen or triamcinolone 0.5% cream may also be used.
Drug treatment (see Table: Drugs Used for Enuresis in Children*) is sometimes helpful but is not typically first-line therapy. Anticholinergic drugs (oxybutynin and tolterodine) 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.
Drugs Used for Enuresis in Children*
Primary urinary incontinence most frequently manifests as nocturnal enuresis.
Constipation should be considered as a contributing source.
Most nocturnal enuresis abates with maturation (15%/yr resolve with no intervention), but at least 0.5% of adults have nighttime wetting episodes.
Organic causes of enuresis are infrequent but should be considered.
Alarms are the most effective treatment for nocturnal enuresis.
Other treatments include behavioral interventions and sometimes drugs.
Parental education is essential to the child’s outcome and well-being.