Voiding Dysfunction 

Updated: Oct 22, 2021
Author: Christopher S Cooper, MD, FACS, FAAP; Chief Editor: Marc Cendron, MD 

Overview

Practice Essentials

The types of voiding dysfunction covered in this article consist of daytime voiding disorders in children who do not have neurologic, anatomic, obstructive, or infectious abnormalities of the urinary tract. The disorders examined result from functional disturbance of the normal micturition cycle. Isolated nocturnal enuresis, which may be considered a form of voiding disorder, is not reviewed here. (See Pathophysiology, Etiology, and Presentation.)

Causes of voiding dysfunction include the following, in isolation or in combination:

  • Uninhibited detrusor contractions ( overactive bladder [OAB])
  • Dysfunction of the pelvic floor musculature (dysfunctional voiding)
  • Decreased force of detrusor contractions (underactive bladder)

Voiding dysfunction is a common problem in children and accounts for as many as 40% of pediatric urology clinic visits. The challenge for clinicians is to differentiate between a pathologic pattern of urgency or incontinence due to an underlying urologic abnormality and benign conditions related to incomplete or abnormal toilet training. (See Epidemiology, Workup, Treatment, and Medication.)

For patient education information, see the Digestive Disorders Center, as well as Constipation in Children, Bladder Control Problems, and Bladder Control Medications.

Pediatric lower urinary tract dysfunction encompasses a wide spectrum of syndromes. Voiding symptoms (ie, urgency, frequency, incontinence) may be transient, intermittent, or persistent. Transient voiding symptoms are commonly encountered due to urinary tract infection (UTI) or as a result of nonspecific urethritis or periurethral irritation due to vaginitis. Symptoms may also occur without a recognized explanation. No notable findings are apparent upon physical examination of a child with voiding dysfunction; however, a thorough examination should be performed to evaluate for other sources of voiding symptoms.

Urinalysis and quantitative urinary culture should be performed to evaluate for UTI. Evaluation of patients with suspected dysfunctional voiding should be performed by a urologist, and may include voiding cystourethrography (VCUG), urinary tract ultrasonography (US), urodynamic studies, and, in some instances, magnetic resonance imaging (MRI) of the lumbosacral spine to rule out a neurologic etiology.

Behavioral modification is the foundation of treatment for children with functional voiding disorders. Effective biofeedback training is especially helpful for management of dysfunctional voiding. Prophylactic antibacterial therapy should be considered in children with recurrent UTIs and in those with vesicoureteral reflux (VUR). Anticholinergic medications may be helpful in children who do not respond to conservative measures but are not long-term solutions. Sacral nerve stimulation is being studied as a means of treating refractory lower urinary tract dysfunction in children.

Pathophysiology

Infants regularly void by detrusor (bladder muscle) contraction as often as hourly, with small voided volumes and incomplete bladder emptying. With increasing age, bladder capacity increases. The coordination between the bladder and sphincter system matures, leading to an improvement in bladder-emptying ability.[1]

Children aged 2-5 years have increased awareness of bladder fullness and develop the ability to void volitionally or to inhibit voiding until it is socially acceptable. During this period, acquisition of cortical control of micturition occurs. Many forms of voiding dysfunction can be thought of as a delay in the acquisition of daytime urinary control, which typically occurs by age 4 years.

Several studies have documented that more than 90% of children achieve full daytime control at age 4 years.[1]  This finding suggests that most children are mature enough for independent volitional control of voiding at this age. Daytime wetting is therefore considered a problem in developmentally normal children aged 4 years or older who are wet several days each week, as well as in previously continent children who develop daytime wetting. (See Presentation.)

The micturition cycle involves the following two discrete processes:

  • Bladder filling and storage of urine
  • Bladder emptying with voiding

These functions are cyclic in nature.

During the filling phase of micturition, regulatory influence of the sympathetic nervous system allows the bladder to expand at low pressure. Urine storage is a coordinated response of the sympathetic-mediated inhibition of detrusor contractile activity. Normal filling requires the absence of involuntary bladder contractions. (The primary neurotransmitter for sympathetic activity is norepinephrine.)

During bladder filling, afferent impulses are transmitted to sensory neurons in the dorsal root ganglia of sacral spinal segments 2-4 and convey information to the brainstem. Nerve impulses from the brainstem during bladder filling inhibit parasympathetic outflow from the sacral spinal micturition center.

Expulsion of urine is mediated by the parasympathetic nervous system (in which the primary neurotransmitter is acetylcholine). During the voiding phase, inhibition of the sacral parasympathetic outflow is removed, and detrusor contraction occurs. At the same time, somatic impulses traveling along the pudendal nerve relax the muscle of the external sphincter. The result is expulsion of urine with minimal outlet resistance.

Central nervous system (CNS) control over the lower urinary tract coordinates the micturition cycle and is initiated in the cerebral cortex. The neural pathway for voiding passes through the pons (Barrington nucleus) and into the spinal cord (Onuf nucleus). Normal development is characterized by increasing awareness of bladder distention and acquisition of the ability to inhibit voiding. Normal voiding frequency in children (after attainment of bladder control or age 5 years) is defined as four to seven voids per day.

Voiding symptoms (ie, urgency, frequency, and incontinence) reflect alterations in urinary bladder function. The pathogenesis of voiding disorders in the neurologically and anatomically intact child who has neither a UTI nor local urethral irritation is best understood and managed when considered as a result of a functional disturbance of the normal voiding cycle (ie, bladder filling with urine storage, followed by bladder emptying with voiding).

Etiology

Causes of voiding dysfunction include the following:

  • Uninhibited detrusor contractions (OAB)
  • Dysfunction of the pelvic floor musculature (dysfunctional voiding)
  • Decreased force of detrusor contractions (underactive bladder)

A study by Oliver et al suggested that children with voiding dysfunction who are underweight, obese, or suffering from a psychiatric disorder or who have recently experienced a stressful event are likely to have a greater lower urinary tract symptom score (as measured through a symptom questionnaire) than other children with voiding dysfunction.[2] In the report, which involved 358 patients (age range, 6-17 years) with nonneurogenic lower urinary tract dysfunction, obesity was found in 28.5%, a recent life stressor in 31.8%, and a comorbid psychiatric disorder in 22.9%. Younger age was also associated with a higher symptom score.

Overactive bladder

OAB (also referred to as detrusor instability, hyperactive bladder syndrome, urge syndrome, and urge incontinence) is the result of overactive detrusor contractions during the filling phase of micturition. Detrusor overactivity is the most common voiding dysfunction in children.

Uninhibited detrusor contractions are thought to result from a lack of inhibitory cerebral control over detrusor contractions during bladder filling. Theories on the cause of OAB have included maturation delay, prolongation of infantile bladder behavior, and abnormality of acquired toilet training habits.

OAB can also occur in children with recurrent UTIs and is a risk factor for UTI. This voiding disorder may contribute to persistence of VUR and to the recurrence of VUR after ureteral reimplantation.

Dysfunctional voiding

Although the etiology is unknown, dysfunctional voiding is thought to reflect a deviation in the normal development of urinary control. As daytime urinary control is achieved, many children go through a transitional phase in which pelvic withholding maneuvers are used to prevent incontinence. Most children then develop a pattern of coordinated voiding that makes it unnecessary to contract the external sphincter to prevent incontinence.

However, some children who have a delay in establishing cerebral control over detrusor contractions continue to use pelvic-tightening maneuvers, and these maneuvers appear to become involuntary over time. Others have suggested that dysfunctional voiding can result from overtraining of the urinary bladder.

A report by Colaco et al indicated that an association exists between a child's temperament and the development of dysfunctional voiding.[3] In a study of 50 children, the investigators found that effortful control tended to be lower in boys with dysfunctional voiding than in those without it. In girls, there was a greater prevalence of urgency among those with dysfunctional voiding.

Underactive bladder

Urinary incontinence in underactive bladder syndrome is usually due to overflow from a large, hypotonic bladder. Patients with persistent voiding symptoms or UTIs should undergo urodynamic evaluation.

Epidemiology

United States statistics

OAB is the most common lower urinary tract dysfunction in children; it appears to have a peak incidence between te ages of 5 and 7 years.[4] In a cross-sectional study, lower urinary tract dysfunction symptoms were detected in 21.8% of school-aged children. The most common urinary symptoms included holding maneuvers (19.1%) and urgency (13.7%).[5] Urge incontinence was reported in 7% of girls and in 3% of boys.

Another study, of 583 children aged 5-9 years, showed that urinary urgency and pelvic-tightening maneuvers to postpone voiding and prevent leakage were the most common voiding problems.[6]

International statistics

A large (N = 2856) 2009 study from Australia addressed the frequency of voiding disorders in school-aged children.[7] This study reported that 17% of children had experienced daytime incontinence in the previous 6 months. Independent risk factors for daytime incontinence included nocturnal enuresis, female sex, history of UTI, and encopresis.

Age-related demographics

The prevalence of daytime wetting with a frequency of at least once every 2 weeks, as reported in different age groups, is as follows[8] :

  • Age 5-6 years - 10%
  • Age 6-12 years - 5%
  • Age 12-18 years - 4%

A functional voiding disorder in a neurologically and anatomically healthy child is not usually recognized before the acquisition of daytime urinary control.

Many children have a transient period of urinary urgency, occasionally with wetting accidents, when daytime continence is first being achieved. Most of these children develop normal urinary control in a relatively short period; however, some children may have persistence of urinary urgency and wetting.

Other children may have a normal voiding pattern until a UTI or an emotionally traumatic event triggers the onset of voiding symptoms.

Sex-related demographics

Studies on the prevalence of voiding disorders in school children indicate that daytime urinary incontinence is two to five times more common in girls.[7]

Prognosis

The prognosis for complete or partial resolution of a functional voiding disorder is excellent for children with daytime urinary incontinence and detrusor instability.

Children with voiding dysfunction appear to be more likely to have adult OAB or voiding dysfunction. Several studies have reported that childhood incontinence in girls is a risk factor for urge symptoms and severe incontinence as adult women.[9, 10]

The prognosis is good for children with giggle incontinence (involuntary complete bladder evacuation induced by laughter), who tend to outgrow it during adolescence. A resolution rate of 89% was reported in children with this condition who were treated for detrusor instability.[11] The prognosis is also good for children with underactive bladder syndrome. The prognosis is guarded, however, for those few children with dysfunctional voiding whose condition does not respond to intervention.

A study of long-term functional and psychosocial outcomes in adolescents and young adults treated during childhood for lower urinary tract dysfunction found that whereas these patients, compared with healthy age-matched control subjects, were more likely to report urinary tract symptoms whe  older, especially if treatment duration was extensive, their general quality of life and psychosocial well-being later in life were unaffected or only mildly affected.[12]

 

Presentation

History

Pediatric lower urinary tract dysfunction encompasses a wide spectrum of syndromes. Voiding symptoms (ie, urgency, frequency, incontinence) may be transient, intermittent, or persistent. Transient voiding symptoms are commonly encountered as a consequence of urinary tract infection (UTI) or as a result of nonspecific urethritis or periurethral irritation due to vaginitis. Symptoms may also occur without a recognized explanation.

A detailed voiding diary provides documentation of voiding habits, frequency of micturition, voided volumes, number and timing of incontinence episodes, and fluid intake.[13]

Various symptom questionnaires have been composed as aids to diagnosis of pediatric bowel and bladder dysfunction. Most are capable of good discrimination, but a large amount of heterogeneity exists in their psychometric testing and validation process.[14] In a study by Anwar et al, an 18-item, five-point questionnaire was found to be a valid and reliable method for diagnosing pediatric bladder and bowel dysfunction and classifying patients into subcategories on the basis of their specific symptoms.[15]

Overactive bladder

The hallmark symptom of overactive bladder (OAB) in children is urgency, and children with this symptom can be clinically diagnosed based on the definition by the International Children’s Continence Society.[16] A careful history usually reveals that the child has had ongoing urinary urgency. The children are commonly evaluated because of daytime urinary incontinence or UTI.

Children with OAB may have a history of holding maneuvers, such as standing on tiptoes, crossing of the legs, or squatting with the heel pressed into the perineum.

The clinician may find that OAB has been present in a patient since the child began developing daytime urinary control or that it arose in a child who previously had a normal voiding pattern. The appearance of OAB in a child who previously had daytime urinary control may occur after a UTI or may appear with no apparent triggering event.

Dysfunctional voiding

Dysfunction of the pelvic floor musculature (dysfunctional voiding) involves failure to relax the urethra and pelvic floor muscles with voiding. It is caused by involuntary contraction of the urethral sphincter or pelvic floor muscles during the voiding phase of the micturition cycle. This pattern of voiding incoordination in a child with a neurogenic bladder is called detrusor sphincter dyssynergia.

Dysfunctional voiding symptoms vary from mild daytime frequency and postvoid dribbling to daytime and nighttime wetting, urgency, urge incontinence, pelvic holding maneuvers, and UTIs. In the most severe form, children with dysfunctional voiding resemble those with neurogenic bladder or anatomic bladder outlet obstruction.

Children with this condition can have increased intravesical pressure upon voiding, incomplete bladder emptying, UTIs, persistent vesicoureteral reflux (VUR), dilatation of the upper tract (hydronephrosis), or, rarely, renal damage.

Giggle incontinence

Giggle incontinence is the occurrence of involuntary complete bladder evacuation induced by laughter. (In some children, episodes of incontinence may occur with giggling, whereas in others, they are induced only by vigorous laughter.) The etiology is unknown; the condition is not a form of stress incontinence, nor is it due to weakness of the sphincter. Giggle incontinence typically appears in children aged 5-7 years. The problem can persist throughout the school years but usually improves or disappears with age. The child’s voiding pattern is otherwise normal.

The authors of one study found a high incidence of daytime voiding symptoms in patients in whom they diagnosed giggle incontinence.[11] The authors concluded that laughter induced unstable detrusor contractions in children susceptible to detrusor instability.

Underactive bladder

Underactive bladder syndrome describes children who void infrequently. The condition is diagnosed if a child voids three or fewer times in 24 hours or if he or she does not void for 12 hours. These children may also use abdominal straining to void.

The pattern of infrequent voiding is clinically important. The detrusor muscle may be hypocontractile, and voiding may be accomplished by using increased intra-abdominal pressure (abdominal straining) as the driving force to expel urine. The diagnosis may be confirmed by means of a urodynamic study.

The voiding pattern in underactive bladder may be a variant of normal. If the condition is identified, however, the voiding pattern should be treated with behavioral modification of the child's voiding regimen.

Constipation

When chronic constipation has been present in a child with a voiding disorder, it may be the primary cause of bladder dysfunction.

There is a close association between fecal retention and OAB. In fact, the two conditions are so frequently associated that the term dysfunctional elimination syndrome (DES) has been introduced in the literature.[17]

The effects of constipation on bladder function may be related to the direct effect of retained fecal material distending the rectosigmoid colon, or it may be the result of shared neural input.

Many children and families are reluctant to discuss stooling history. Often, neither the child nor the parent appears to have accurate information about stooling frequency or character.

Indicators of constipation include the following:

  • Infrequent passage of stools
  • Small, hard stools or elongated, wide-bore stools
  • Encopresis
  • Palpable stool on abdominal examination
  • Soiling in the underwear (often misinterpreted as being due to improper or careless wiping)
  • Large quantities of stool in the colon, especially the rectosigmoid area as seen on abdominal radiography

Other factors that may result in daytime wetting

Many children aged 3-5 years tend to delay urination because of intense concentration on playing or watching television. As a result, they occasionally have damp or soaked clothing. If the child’s voiding pattern is otherwise normal, this pattern of voiding dysfunction usually subsides when an increased effort is made toward scheduled voiding. One study of an initial trial of timed voiding reported that 45% of patients had a significant improvement in the frequency of wetting.[18]

Vaginal reflux of urine from voiding in a knees-closed position can cause dampness when the child assumes an upright posture after voiding or postvoid dribbling.

Labial adhesions of the labia minora may cause daytime wetting as a result of the pooling of urine in the vagina. Treatment of the labial adhesions eliminates this cause of urinary incontinence.

If incontinence is persistent and continually ongoing, an ectopic ureter should be suspected and should prompt evaluation by a urologist, who can often make the diagnosis on the basis of renal ultrasonography (US), voiding cystourethrography (VCUG), and physical examination findings.

The diagnosis of a neurogenic bladder is usually evident from the patient's history; occasionally, occult neuropathic bladder dysfunction can be discovered based on evaluation for urinary symptoms.

Daytime wetting in a previously continent child should prompt the clinician to consider the possibility of sexual abuse or other trauma.

Physical Examination

No notable findings are apparent upon physical examination of a child with voiding dysfunction; however, a thorough examination should be performed to evaluate for other sources of voiding symptoms.

A careful physical examination is waranted to rule out an abnormality of the lumbosacral area that would suggest the presence of occult spinal dysraphism. Signs of this condition include a sacral dimple or tuft of hair, dermal vascular malformations, a small lipomeningocele, or absence of the gluteal cleft with flattened buttocks.

The neurologic examination should include assessment of motor strength, deep tendon reflexes, perineal sensation, gait, and coordination.

Carefully examine the patient’s genitalia to be certain that they are normal. Look for labial adhesions in girls and meatal stenosis in boys. In girls, the genitalia should be examined to evaluate for sexual abuse. One study reported that 6% of a group of patients (89% of whom was female) evaluated for voiding dysfunction had a history of sexual abuse.[19] Rashes in the perineal or genital areas may indicate fungal infections that result from chronic wetness.

Complications

Children with daytime wetting have a higher rate of parent-reported psychological problems than do children who have no daytime wetting. This has been found to be the case in children as young as age 7 years.[20]

Persistence of daytime wetting may markedly disrupt the social lives of older children. Daytime wetting can negatively affect self-esteem and is a major stressor in school-age children. In a study of 2000 children that looked at their perceptions of potential stressful events, wetting in school ranked behind only parental death and going blind.[21]

Skin irritation and rashes may result from chronic wetness. Children should be monitored for skin breakdown. Topical antifungal therapy may also be initiated for those with tinea.

Detrusor instability with pelvic holding maneuvers may foster recurrent UTIs or persistence of VUR. In a study by Avlan et al, the rates of VUR, UTI, and renal damage in patients with OAB plus dysfunctional voiding or with pure dysfunctional voiding were higher than in patients with OAB alone.[22]

Other studies found VUR and recurrent UTIs in, respectively, 16-20% and as many as 60% of children with voiding dysfunction.[23, 24]

In rare cases, dilatation of the upper urinary tract (hydronephrosis) and kidney damage caused by recurrent infections may occur. The dilation of the upper tract is secondary to high storage pressures. This pressure can induce secondary reflux. The pressure and kidney infections cause kidney damage.

A few children with functional voiding disorder have marked dysfunctional voiding (ie, nonneurogenic bladder [Hinman-Allen syndrome]) and may incur significant renal damage. Inappropriate contraction of the external urinary sphincter during voiding and subsequent elevation of the intravesical pressure is the typical pathology. Daytime or nighttime wetting, recurrent UTI, constipation, and increased postvoid residual urine volume in the absence of a neurologic lesion are the dominant clinical features.[25]

 

DDx

Diagnostic Considerations

Voiding disorder symptoms caused by local factors usually clear after the irritant is removed and the local inflammation subsides. Local factors include the following:

  • Detergents in bubble bath or shampoo, which may remove protective secretions from the urethral mucosa
  • Mechanical and chemical irritation from urine-soaked underclothes
  • Local irritation due to tight undergarments

Constipation can be the primary or contributing cause of a voiding disorder; therefore, constipation should always be considered in the evaluation of a child with voiding symptoms.

Differential Diagnoses

 

Workup

Approach Considerations

Urinalysis and quantitative urinary culture should be performed to evaluate for urinary tract infection (UTI). On urinalysis, the specific gravity (concentration) of the urine is noted, as is any evidence of underlying voiding problems based on the presence of hematuria, proteinuria, or glucosuria.

Evaluation of patients with suspected dysfunctional voiding should be performed by a urologist, and may include voiding cystourethrography (VCUG), urinary tract ultrasonography (US), urodynamic studies, and, in some instances, magnetic resonance imaging (MRI) of the lumbosacral spine to rule out a neurologic etiology.

If dribbling and ongoing wetting have been lifelong problems, the patient should be evaluated for an ectopic ureter.

Noninvasive uroflowmetry (commonly in conjunction with pelvic floor electromyography [EMG][26, 27] ) and postvoid residual urine quantification (bladder US or scanning) are useful, noninvasive tools in evaluating children for lower urinary tract dysfunction.

Urodynamic testing is not usually required. In select cases, however, urodynamic studies should be performed to detect uninhibited detrusor contractions, dysfunction of the pelvic floor muscles, or a hypotonic bladder.

Any child with evidence of neurologic dysfunction (eg, cutaneous signs, physical examination findings, severely refractory voiding dysfunction, or urodynamic evidence of neurogenic bladder) should be further evaluated for occult neurologic lesions.

Special equipment for uroflow, bladder US, and urodynamics is typically available only at urologic facilities.

 

Treatment

Approach Considerations

Behavioral modification is the foundation of treatment for children with functional voiding disorders. Effective biofeedback training is especially helpful for management of dysfunctional voiding, primarily by decreasing outlet resistance during voiding. Children younger than 5 years are often incapable of doing biofeedback on a regular basis.[28] Animated biofeedback has been shown to effectively treat dysfunctional voiding in the pediatric population.[29, 30]

One study of children with daytime incontinence reported that as many as 76% of these patients never had an adequate trial of preliminary nonpharmacologic measures.[18]

Sacral nerve stimulation is being studied as a means of treating refractory lower urinary tract dysfunction in children.[31]  Some evidence suggests that it may be as effective as biofeedback for treating nonneurogenic voiding dysfunction.[32]

Overactive Bladder

In the treatment of overactive bladder (OAB), the goal is to foster development of cerebral inhibition of detrusor contractions during bladder filling so that urgency and urge incontinence do not occur. No known medication or procedure has been shown to accomplish this; however, certain interventions appear to help.

A voiding retraining program is an essential component of management. In most instances, such retraining should be tried for 1-2 months before an anticholinergic medication is introduced.

One study evaluated the response to treatment in 63 children with daytime incontinence initially treated with nonanticholinergic methods; by the second visit, 6% of patients were dry, 38% showed significant improvement, and 37% showed slight improvement.[18]

Guidelines for voiding retraining with behavioral modifications

Children should have a footstool or other solid surface placed in front of the commode so that their feet are on a solid surface. The child should remove the underpants or lower them to the ankles to permit relaxed separation of the thighs. During voiding, the child should be comfortable and relaxed and should not be rushed to void (eg, during a television commercial).

Boys should be instructed to free the penis before voiding. The zipper or buttons should be completely opened. If the underwear constricts the penis, this should be corrected. Boys should be relaxed and take sufficient time to empty the bladder completely.

Successful management requires ongoing support, instruction, and education. Children should be taught to understand that normal urination is the result of relaxing the sphincters and permitting the bladder muscle to expel the urine, not a matter of forced voiding using the abdominal muscles.

A timed voiding schedule, to be used when the child is awake, is an essential component of bladder retraining, even in patients with urinary frequency. Children should be encouraged to void before a sense of urgency is present in order to develop a regular voiding pattern. Timed voiding is instituted with bladder evacuation every 2-3 hours “by the clock” when the child is awake.

Writing letters to a school nurse, teacher, or principal to carry out this program is necessary and of value. In a survey of school nurses, 47% of respondents reported being involved in setting voiding schedules for children, and the majority allowed free access with a physician’s note.[33]

Introduce calendars to keep records of voiding patterns and bowel movements. The latter is important, even in a child with no history of constipation, particularly if an anticholinergic medication is introduced.

Pharmacologic treatment

Prophylactic antibacterial therapy should be considered in children with recurrent urinary tract infections (UTIs) and in those with vesicoureteral reflux (VUR).

Anticholinergic medications (eg, oxybutynin[34] ) are frequently helpful in children who do not respond to conservative measures. However, these medications are meant to help the child develop a normal voiding pattern and are not long-term solutions. Ultimately, the child must develop the ability to use cerebral mechanisms to inhibit detrusor contractions.

Parasacral trancutaneous electrical nerve stimulation

Various reports have suggested that parasacral trancutaneous electrical nerve stimulation (TENS) can be useful in treating OAB. It appears to be more effective than oxybutynin, with fewer adverse side effects.[34] Its usefulness does not appear to be affected by sex, age, daytime incontinence, nocturia, previous UTI, constipation, or holding maneuvers; however, it may be less likely to be effective in the presence of nocturnal enuresis.[35, 36]

Constipation and overactive bladder

Prevalence figures for constipation in the pediatric population have ranged from 0.7% to 29.6%.[37] When constipation is diagnosed in a child with voiding dysfunction, it is important to treat the constipation so as to determine whether it is the cause of the bladder symptoms. In one study of the relation between constipation and incontinence, resolution of constipation was associated with 89% resolution of concomitant urinary incontinence.[38]

Treatment of chronic constipation includes a high-fiber diet, sometimes with the addition of laxative medication. One option is treatment with MiraLAX, which is prepared by diluting the powder and administering it at least once a day. This therapy has gained widespread use for constipation. A study of 46 children with urinary incontinence and constipation treated with MiraLAX found that 39% of patients became dry, 56% of patients had improvement in their wetting, and 5% of the children had no improvement.[39]

Dysfunctional Voiding

Dysfunctional voiding is the most worrisome functional voiding disorder in children because in rare cases it progresses in a pattern similar to a neurogenic bladder or outlet obstruction. In the infrequent instances in which severe bladder dysfunction occurs, the condition has been termed nonneurogenic neurogenic bladder (Hinman-Allen syndrome).

Treatment of this voiding disorder, which has been described as a disharmony between the detrusor and sphincters, consists of a voiding retraining program with emphasis on good voiding technique and suppressive antibacterial agents for patients prone to UTIs. Anticholinergic medication is not useful to treat sphincter dysfunction. Botulinum toxin A has been reported to achieve satisfactory results in selected children with refractory voiding dysfunction.[40]

When the upper urinary tract is normal, management should focus on the development of effective, relaxed voiding using the interventions described for OAB. Biofeedback training for carrying out Kegel exercises (pelvic floor relaxation and contraction) has been successful in many centers.[41] Animated biofeedback has also been reported to effectively manage dysfunctional voiding.[29, 30, 40]

Giggle incontinence

Treatment results for giggle incontinence are difficult to assess because of the high rate of spontaneous resolution with maturity. Patients may need to accommodate the problem by trying to avoid situations that cause laughter when in public places. If incontinence frequently occurs, a trial of a timed voiding schedule with the addition of an anticholinergic agent may be warranted, and high rates of success have been reported.

An uncontrolled study of seven children with giggle incontinence reported success with methylphenidate. The report’s authors suggested that the condition responded to a stimulant because, possibly, giggle incontinence shares pathophysiologic features with narcolepsy/cataplexy syndrome.[42]  Biofeedback and bladder training have been advocated by those who place more emphasis on urologic dysfunction than on neurologic origin as an explanation for giggle incontinence.[43]  

Incontinence upon laughter may have symptoms similar to those of OAB, and a treatment regimen including anticholinergics has been described as yielding a success rate of 89%.[11]

Underactive Bladder

Not all patients with detrusor underutilization are found to have detrusor underactivity or overactivity, with the majority of patients generating a normal sustained voiding contraction that empties the bladder completely and in synergy with the sphincter.[44]

Chronic or episodic willful deferring of voiding by patients can occur. Children who void as infrequently as two or three times every 24 hours should be encouraged to undertake more frequent voiding to avoid potential problems at a later age. They are at risk for UTIs because prolonged bladder incubation of urine compromises the protective effect of regular bladder emptying, which clears bacteria that gain access to the bladder during voiding.

Children with large-capacity, hypotonic urinary bladders who are unwilling or unable to comply with an improved voiding schedule can benefit from clean intermittent catheterization (CIC).

A randomized clinical study of 36 children with nonneuropathic underactive bladder found that the combination of transcutaneous interferential electrical stimulation (IFES) and urotherapy was safe and effective in the management of pediatric patients with this condition.[45]  A review of 11 studies assessing transcutaneous IFES for lower urinary tract dysfunction and urinary incontinence cited success rates ranging from 61% to 90%.[46]

 

Other Sources of Incontinence

Wetting secondary to vaginal reflux may be resolved by teaching the child proper voiding technique. The child may void in a reverse sitting position on the commode, which causes the thighs to be abducted and the labia majora to separate. If this is unsuccessful, the child may assume an upright position over the commode immediately after voiding to empty the vagina.

Labial adhesions have been attributed to local inflammation and a hypoestrogenic state in a preadolescent child. The labial skin can become so excoriated and denuded that during the healing process, the labial edges fuse together. Symptoms, if present, are usually vulvar irritation or soreness. The child may also present with “incontinence,” when dribbling of urine occurs as a result of urine being trapped in the vagina.

Recommended treatment of labial adhesions consists of conservative observation, application of a topical estrogen cream to only the fused area, or physician lysis of adhesions. After the adhesions have separated, a bland petroleum jelly should be applied to the medial surfaces of the labia minora once daily for 1-2 months.

If no specific diagnostic etiology is found, management of persistent and otherwise asymptomatic daytime urinary incontinence is primarily supportive.

Consultations

Reasons to have a patient's condition evaluated by a urologist include the following:

  • Suspicion of neurologic or anatomic etiology
  • Lack of familiarity or training in diagnosis and treatment of children with voiding dysfunction
  • Symptoms that are not responsive to behavioral modification
  • Constant, continuous incontinence
  • Frequent UTIs
  • VUR
  • Suspected renal involvement (elevated creatinine levels, hydronephrosis)
 

Medication

Medication Summary

Pharmacologic therapy for voiding dysfunction in children usually centers on treating OAB (uninhibited detrusor contractions) during filling and, at times, decreasing bladder outflow resistance. Most of the neurohumoral stimulus for bladder contraction is the stimulation of muscarinic-cholinergic receptor sites on bladder smooth muscle. Anticholinergic agents can depress uninhibited bladder contractions, making this class of medications the mainstay of pharmacologic management of overactive bladder.

However, the effects of anticholinergic drugs on normal contractions, with subsequent incomplete bladder emptying and retention, must also be considered. In addition, certain anticholinergic medications may exacerbate constipation, as they affect the intestinal musculature. In rare instances, bladder outlet resistance is increased because of stimulation of alpha1-adrenergic receptors in the bladder neck; this effect may be decreased by the use of alpha1-adrenoreceptor blockers.

Despite the prevalence and significance of pediatric daytime incontinence, few prospective, randomized trials assessing treatments have been published. This problem was documented by a 2003 review of studies of pediatric incontinence that found only 1 randomized, controlled study that evaluated currently used treatment; that study reported no benefit in the combination of biofeedback and the anticholinergic drug oxybutynin.[47]

Oxybutynin is approved by the US Food and Drug Administration (FDA) for the treatment of OAB in children and has traditionally been the treatment of choice.

In an attempt to define predictive factors that affect the continence outcome in children with daytime wetting, a study evaluated 81 children treated with oxybutynin for an average of 1.2 years. At the last visit while taking oxybutynin, 38% of patients were dry, 31% of patients were significantly improved, 24% of patients were slightly improved, and 7% of patients were unchanged in their symptoms.[48] The only variable significantly associated with improvement in daytime wetting with oxybutynin was the frequency of wetting episodes; those who presented with fewer wetting episodes were more likely to become dry.

One study reviewed 27 children who were changed from immediate-release oxybutynin to the extended-release form.[49] All patients had persistent incontinence while taking regular oxybutynin. By the first visit after changing to the extended-release formulation, however, 48% of the children had become dry or had experienced significant improvement in the frequency of wetting. Voided volume and bladder capacity were also improved.

In addition, fewer adverse effects have been reported for extended-release oxybutynin than for the immediate-release agent.[50]

Oxybutynin is also available in a patch (Oxytrol), as well as a gel (Gelnique). However, neither of these formulations has been approved for use in the pediatric population.

Antispasmodic Agents, Urinary

Class Summary

These drugs competitively inhibit the binding of acetylcholine to the muscarinic cholinergic receptor, thereby suppressing involuntary bladder contraction of any etiology. In addition, they increase the volume at the first involuntary bladder contraction, decrease the amplitude of the involuntary bladder contraction, and, possibly, increase bladder capacity.

Oxybutynin (Ditropan XL, Gelnique, Oxytrol)

This drug is a synthetic tertiary amine that, like atropine, antagonizes the muscarinic actions of acetylcholine. Oxybutynin has a direct spasmolytic effect on detrusor muscle and small intestine and local anesthetic action. It reduces the incidence of uninhibited detrusor contractions.

Alpha1-Adrenergic Antagonists

Class Summary

These agents are used to decrease smooth muscle tone in the bladder outlet. A study of doxazosin in dysfunctional voiding associated with urinary retention showed an 88% reduction in residual urine. A placebo-controlled trial, however, did not show an objective benefit.[51]

Alpha-blocker therapy has demonstrated continued benefit in children with primary bladder neck dysfunction after 3 years of treatment.[52]

Doxazosin mesylate (Cardura, Cardura XL)

Doxazosin is a selective inhibitor of alpha1-adrenergic receptors. Blockade of these receptors in the bladder neck decreases outflow resistance.

Terazosin (Hytrin)

Terazosin hydrochloride is a selective inhibitor of alpha1-adrenergic receptors. Blockade of these receptors in the bladder neck decreases outflow resistance.

Laxatives, Osmotic

Class Summary

These agents are useful when treating constipation and detrusor instability.

Polyethylene glycol-3350 powder for PO solution (MiraLAX, GlycoLax, Glavilax, HealthyLax)

Polyethylene glycol solution is an osmotic agent that causes water to be retained in stool. Despite a lack of specific recommendations, it is widely given to children with voiding dysfunction by primary care physicians, pediatric gastroenterologists, and pediatric nephrologists. The agent is recommended for occasional constipation in adults.