eMedicine Specialties > Pediatrics: Surgery > Urology

Voiding Dysfunction: Treatment & Medication

Author: Christopher S Cooper, MD, FACS, FAAP, Associate Professor of Urology, Director of Pediatric Urology, University of Iowa, Children's Hospital of Iowa; Associate Dean for Student Affairs and Curriculum, University of Iowa Carver College of Medicine
Coauthor(s): Kenneth G Nepple, MD, Resident Physician, Department of Urology, University of Iowa Hospitals and Clinics; Stanley Hellerstein, MD, Pediatric Nephrologist, Children's Mercy Hospital of Kansas City; Ernest L Glasscock, MD Chair in Pediatric Research, Professor of Pediatrics, University of Missouri School of Medicine at Kansas City
Contributor Information and Disclosures

Updated: Jun 24, 2008

Treatment

Medical Care

• OAB (detrusor instability)
  • 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, the voiding retraining program should be tried for 1-2 months before an anticholinergic medication is introduced. One study reported as many as 76% of children with daytime incontinence never had an adequate trial of preliminary nonpharmacologic measures. 
  • 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% of patients showed significant improvement, and 37% of patients showed slight improvement.⁶
  • Guidelines for a voiding retraining program include the following:
    • 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 his or her underpants or lower them to the ankles to permit relaxed separation of the thighs. During voiding, the child should be comfortable and relaxed and not rushed to void (eg, during a television commercial).
    • Boys should be instructed to free their 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 completely empty the bladder.
    • 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 should be used when the child is awake, even in those with urinary frequency. Children should be encouraged to void before a sense of urgency is present in order to develop a regular voiding pattern. Time voiding is instituted with bladder evacuation every 2-3 hours “by the clock” when the child is awake. This is an essential component of bladder retraining. Writing letters to a school nurse, teacher, or principal to carry out this program is necessary and of value.
    • Introduce calendars to keep records of voiding patterns and bowel movements. The latter is important, even in the child with no history of constipation, particularly if an anticholinergic medication is introduced.
  • Prophylactic antibacterial therapy should be used in children with recurrent UTIs and in those with VUR.
  • Anticholinergic medications (see Medication) 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.
• Constipation and detrusor instability
  • When constipation is diagnosed in a child with voiding dysfunction, treating the constipation is important to determine if it is the cause of the bladder symptoms. In one study of the relationship between constipation and incontinence, resolution of constipation was associated with 89% resolution of concomitant urinary incontinence.⁷
  • Treatment of chronic constipation includes a high-fiber diet, sometimes with the addition of laxative medication. One option is treatment with Miralax (see Medication), which is prepared by diluting the powder and administering it once a day or more frequently. This therapy has gained widespread use for constipation. One 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 only 5% were unchanged.⁸
• Other sources of 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 addition of an anticholinergic agent with may be warranted. One uncontrolled study of 7 children reported success with methylphenidate as the authors related the condition functionally to cataplexy.⁹
  • 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. Local irritation caused by aggressive cleansing may play a role. Recommended treatment 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.
• Dysfunctional voiding (failure to relax the urethra and pelvic floor muscles while voiding)
  • Dysfunctional voiding is the most worrisome functional voiding disorder in children because, rarely, it can progress in a pattern similar to a neurogenic bladder or outlet obstruction. In the infrequent instances of severe bladder dysfunction 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 those prone to UTIs.
  • When the upper urinary tract is normal, management should focus on the development of effective relaxed voiding using the interventions described for detrusor instability. Biofeedback training for carrying out Kegel exercises (pelvic floor relaxation and contraction) has been successful in many centers.
  • Anticholinergic medication is not useful to treat sphincter dysfunction.
• Underactive bladder syndrome
  • Children who void as infrequently as 2-3 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.
  • Urinary incontinence is usually due to overflow from a large hypotonic bladder. Those with persistent voiding symptoms or UTIs should undergo urodynamic evaluation. Children with large capacity hypotonic urinary bladders who are unwilling or unable to comply with an improved voiding schedule may benefit from clean intermittent catheterization.

Consultations

Reasons to obtain evaluation 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 not responsive to behavioral modification
• Constant continuous incontinence
• UTI
• VUR
• Suspected renal damage (elevated creatinine levels, hydronephrosis)

Medication

Pharmacologic therapy of voiding dysfunction in children usually centers on treating 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, but effects on normal contractions with subsequent incomplete bladder emptying  and retention must also be considered. In rare instances, bladder outlet resistance is increased because of stimulation of alpha1-adrenergic receptors in the bladder neck, and this effect may be decreased by the use of alpha1-adrenoreceptor blockers. 

• Oxybutynin is approved by the US Food and Drug Administration (FDA) for treatment of OAB in children and has traditionally been the treatment of choice.
  • 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 one randomized controlled study that evaluated currently used treatment; that study reported no benefit in the combination of biofeedback and oxybutynin.¹⁰
  • One of the larger studies of oxybutynin evaluated 144 children, two thirds of whom were treated with anticholinergic medication. Follow-up averaged 3.2 years.¹ The study reported symptom resolution or improvement in 91% of children with daytime urinary incontinence, and 56% of those with UTI stopped having infections.
  • 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.¹¹ 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.
• An extended-release formulation of oxybutynin (Ditropan XL) is taken once per day.
  • One study reviewed 27 children who were changed from immediate-release oxybutynin to extended-release.¹² All patients had persistent incontinence while taking regular oxybutynin. Of children with persistent wetting, 48% became dry or had significant improvement in the frequency of wetting by the next visit after changing to the extended-release formulation. Voided volume and bladder capacity were also improved.
  • Studies of oxybutynin extended-release reported fewer adverse effects.¹³

Anticholinergic agents

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

Oxybutynin (Ditropan, Ditropan XL)

Synthetic tertiary amine; like atropine, antagonizes muscarinic actions of acetylcholine. Direct spasmolytic effect on detrusor muscle and small intestine and local anesthetic action. Reduces incidence of uninhibited detrusor contractions.

Alpha1-adrenergic antagonists

These agents are used to decrease smooth muscle tone in the bladder outlet.

One study of doxazosin in dysfunctional voiding associated with urinary retention showed an 88% reduction in residual urine, whereas a placebo-controlled trial did not show an objective benefit.¹⁴

Doxazosin mesylate (Cardura)

Selective inhibitor of alpha1-adrenergic receptors. Blockade of these receptors in bladder neck decreases outflow resistance. Available as tablet.

Terazosin hydrochloride (Hytrin)

Selective inhibitor of alpha1-adrenergic receptors. Blockade of these receptors in bladder neck decreases outflow resistance. Available only as capsule.

Laxatives

These agents are useful when treating constipation and detrusor instability.

Polyethylene glycol-3350 powder for PO solution (Miralax, GlycoLax)

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

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