Constipation and Urologic Conditions

Angelique M. Champeau

Karla M. Giramonti

I. INTRODUCTION

There is a strong correlation between constipation and urologic conditions. Constipation should be considered in the following urological problems.

A. Urinary Tract Infections

1. Approximately one-third of children with recurrent urinary tract infections have associated bowel problems. Infections will recur in most of those whose bowel problems are not treated and in far less of those treated.

2. Approximately 10% of constipated children have recurrent urinary tract infections.

B. Uninhibited Bladder (see Chapter 8)

1. Children with recurrent urinary tract infections and constipation often will have uninhibited bladder contractions. After treatment of the constipation, many will have resolution of the overactive bladder and its associated symptoms (incontinence and recurrent infections).

C. Vesicoureteral Reflux

1. Vesicoureteral reflux is more likely to resolve if concurrent constipation is treated.

2. Constipated children with vesicoureteral reflux are more likely to have breakthrough urinary tract infections and more likely to have postoperative complications.

D. Ultrasound Findings

1. Constipated children can have a significant increase in postvoid residual and upper renal tract dilation compared to children who are not constipated.

E. Incontinence

1. One-third of constipated children will also have daytime urinary incontinence. If constipation is treated, most will have improvement in daytime wetting.

2. One-third of constipated children will have nighttime urinary incontinence. If constipation is treated, then two-thirds will have resolution of nighttime wetting.

III. ETIOLOGY

A. The most common cause of constipation in the otherwise healthy child is “withholding” of stool due to toilet training, dirty or public
bathrooms, lack of privacy, too busy playing, past painful defecation, changes in routine or diet, and/or intercurrent illness. Some children will experience pain with the large stools and will then hold their stool even longer.

B. The action of withholding stool causes the rectum and colon to expand to accommodate the increasing amount of stool. The stool will increase in size and as the body reabsorbs more water, the stool becomes increasingly hard. As the rectum expands the normal urge to defecate diminishes. As the cycle is repeated, greater amounts of stool are built up in the bowel and motility, rectal elasticity, and sensation further decrease. Subsequently, some children will begin to have encopresis due to looser stool leaking around a rectal impaction or because the muscles used to withhold become fatigued.

C. No organic etiology is found in 90% to 95% of children with constipation.

IV. PRESENTATION

A. A child will not typically “present” to the urology clinic with a complaint of constipation. These children will more often present with urologic symptoms such as incontinence or recurrent urinary tract infections.

V. INCIDENCE/EPIDEMIOLOGY

A. Constipation accounts for 3% of pediatric outpatient visits and 25% of gastroenterology visits.

B. Encopresis is present in 1.5% of children at school entry.

C. Boys will suffer from encopresis 3 to 6 times more often than girls. This is thought to be because of the standing versus sitting voiding position used by boys during urination. During urination, the pelvic floor muscles relax, and when the pelvic floor muscles relax, stool in the rectum may be expelled. Since boys stand to urinate, when the pelvic muscles relax with voiding, they may soil their underwear.

VI. DIAGNOSIS

A. History

1. If an accurate clinical history can be obtained, then the diagnosis of constipation can usually be made by history alone. Unfortunately, an accurate bowel history in the school-aged child is close to impossible to obtain in most cases.

2. Parental history of constipation can be incorrect in up to one-half of children, particularly when the children are out of diapers. Children are also not good historians as to their own bowel/bladder habits and generally have no frame of reference for normal bowel habits.

3. When using voiding diaries to document bladder function/dysfunction, tracking bowel movements is an important adjunct.

4. The Bristol stool score/chart can be helpful for parents/children to describe consistency of stool (Fig. 10-1).

B. Physical Examination

1. Abdominal examination may reveal hard stool in the abdomen.

2. External examination of the anus and rectum may reveal large amount of stool at the anus.

3. A brief neurologic examination should assess perianal sensation, anal tone, and the presence of anal wink.

4. Although controversial as it can be traumatic for some children, some clinicians include a formal rectal examination. This can determine the size of the rectum and the amount and consistency of stool.

FIG. 10-1 The Bristol stool score/chart helpful for communicating possible constipation.

C. Radiologic

1. Abdominal x-ray can further support the suspicion of constipation on history or physical examination. Fecal load can be estimated and objective scoring systems have been developed. An abdominal x-ray is especially useful in children in whom a digital examination can be difficult and/or traumatic.

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