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:
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Infrequent passage of stools
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Small, hard stools or elongated, wide-bore stools
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Encopresis
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Palpable stool on abdominal examination
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Soiling in the underwear (often misinterpreted as being due to improper or careless wiping)
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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]
