The colon absorbs water from the stool and serves a reservoir function. These processes depend on colonic motility, which is an area of physiology that is not well understood, and for which treatments of problems are limited. In normal individuals the rectosigmoid stores the stool, and every 24-48 h develops active peristaltic waves indicating that it is time to empty. A normal individual feels this sensation and decides when to relax the voluntary sphincter mechanism. Patients with anorectal malformations, as discussed in Chaps. 29, 30 and 33, lack a normal anal canal, have deficient sphincters, and have an accompanying motility disorder, usually hypomotility [1]. Their ability to have a voluntary bowel movement depends on these three factors. Solid stool allows for distension of the distal rectum, and proprioception allows the child to detect this. It is for this reason that loose stools make their ability to be fecally continent much less likely.

If a child is fecally continent (i.e., those with a good-prognosis anorectal defect, a normal sacrum, good sphincters, and an intact rectosigmoid), then management involves the treatment of constipation using laxatives, which help provoke peristalsis and overcome the dysmotility disorder. Patients in whom the rectosigmoid was resected, a common part of older operations for anorectal malformations, have hypermotility and require treatments that slow down the colon. Unfortunately, most of these patients are fecally incontinent because their lack of anal canal, and deficient sphincters cannot hold back the loose stool. They do not detect rectal fullness and thus cannot rely on proprioception for help with a voluntary bowel movement. For patients with fecal incontinence, a bowel management program is a way to artificially keep patients clean (Chaps. 29, 30 and 33). For the majority of patients (75%), management consists of avoidance and treatment of constipation, and toilet-training strategies.

Constipation in anorectal malformations is extremely common, particularly in the more benign types [2]. When left untreated, constipation can be extremely incapacitating, and in its most serious forms can produce a form of fecal incontinence known as overflow pseudoincontinence. Diet impacts colonic motility, but its therapeutic value is negligible in the most serious forms of constipation. It is true that many patients with severe constipation suffer from psychologic disorders, but a psychologic origin cannot explain the severe forms as it is not easy to voluntarily retain the stool when an otherwise autonomous rec-tosigmoid peristalses. Passage of large, hard pieces of stool may provoke pain and make the patient behave like stool retainers. This may complicate the problem of constipation; but it is not the original cause.

The clinician must decide which type of patient he or she is dealing with. Patients with a good prognosis are those more likely to have constipation, and while they are in disapers, aggressive, proactive treatment of their constipation is the best approach. Once they reach the age of toilet training, the child must have the capacity for voluntary bowel movements before employing treatment for constipation. Otherwise, theys require bowel management and enemas.

Most of these patients suffer from different degrees of dilatation of the rectum and sigmoid, a condition defined as megarectosigmoid, due to a hypomotility disorder that interferes with complete emptying of the rectosigmoid [1]. These children are born with a good-prognosis type of anorectal defect and underwent a technically correct operation, but did not receive appropriate treatment for constipation. They therefore developed fecal impaction and overflow pseudoincontinence. The impaction needs to be removed with enemas and colonic irrigations to clean the megarectosigmoid. The constipation is subsequently treated with the administration of large doses of laxatives. The dosage of the laxative is increased daily until the right amount of laxative is reached in order to completely empty the colon every day. If medical treatment proves to be extremely difficult because the child has a severe megasigmoid and requires an enormous amount of laxatives to empty, the surgeon can offer a resection of the sigmoid colon. After the sigmoid resection, the amount of laxatives required to treat these children can be significantly reduced or even eliminated. Before performing this operation it is mandatory to confirm that they are definitely suffering from overflow pseudoincontinence rather than true fecal incontinence with constipation. Failure to make this distinction may lead to an operation in which a fecally incontinent constipated child is changed to one with a tendency to have loose stool, which will make them much more difficult to manage (see Chaps. 29, 30 and 33).

When managed from the beginning, with aggressive treatment of constipation, children with a good prognosis should toilet train without difficulty. When constipation is not managed properly and a patient presents after many years, they behave much like children with idiopathic constipation, and may have overflow pseudoincontinence.

On occasion, the constipation in anorectal malformations is attributed to Hirschsprung's disease, and it is not uncommon that clinicians perform a rectal biopsy. In our experience, Hirschsprung's disease is no more common in patients with anorectal malformations than in the general population and we do not routinely biopsy these patients.

Constipation in anorectal malformations is a self-perpetuating disease. A patient who suffers from a certain degree of constipation and who is not treated adequately only partially empties the colon, leaving larger and larger amounts of stool inside the recto-sigmoid, which results in greater degrees of megasig-moid. It is clear that dilatation of a hollow viscus produces poor peristalsis, which explains the fact that constipation leads to fecal retention, thereafter mega-colon, which exacerbates the constipation. In addition, the passage of large, hard pieces of stool may produce anal fissures, which result in a reluctance by the patient to have bowel movements.

The clinician must accept the fact that the dys-motility associated with anorectal malformations is essentially incurable. It is manageable, however, but requires careful follow-up for life. Most importantly, it must be anticipated and treated early, even within weeks following the colostomy closure. Treatments cannot be given on a temporary basis; once they are tapered or interrupted, constipation recurs.

Some clinicians treat such patients with colostomies or colonic washouts via a catheterizable stoma or button device, and monitor the degree of colonic dilatation with contrast studies. Once the distal colon regains a normal caliber, the physician assumes that the patient is cured and the colostomy is closed or the washouts are discontinued with the predictable return of symptoms. Washouts are really only for patients with fecal incontinence who are incapable of having voluntary bowel movements and thus require a daily irrigation to empty. The patients described in this chapter are capable of emptying their colon with the help of adequate doses of laxatives.

Determining if the patient is continent or incontinent is the challenge. If incontinent, washouts with a bowel management regimen are appropriate. If continent, then aggressive management of the constipation after ensuring disimpaction is the appropriate treatment. These latter patients have a good-prognosis anorectal defect, good sacrum, and good sphincters.

Fecal impaction is a stressful event defined as a condition of retained stool for several days or weeks, crampy abdominal pain, and sometimes tenesmus. When laxatives are prescribed to such a patient the result is exacerbation of the crampy abdominal pain and sometimes vomiting. This is a consequence of an increased colonic peristalsis (produced by the laxative) acting against a fecally impacted colon. Therefore, disimpaction, proven by x-ray, must precede the initiation of laxative therapy.

Soiling of the underwear is an ominous sign of bad constipation. A patient who at an age of bowel control soils the underwear day and night and basically does not have spontaneous bowel movements may have "overflow pseudoincontinence." These patients behave as fecally incontinent individuals. When the constipation is treated adequately, the great majority of these pseudoincontinent children regain bowel control. Of course, this clinical presentation may also occur in a patient with anorectal malformation and true fecal incontinence. In such a patient with a poor-prognosis defect, poor sacrum, and poor sphincters, bowel management with a daily enema is needed (see Chaps. 29, 30 and 33).

When uncertain, we usually start the 3.5 to 4 year-old child having trouble with toilet training on a daily enema, and once clean with this regimen, and if they have the potential for bowel control, then try a laxa tive program. A contrast enema with a hydrosoluble material (never barium) is the most valuable tool that, in the constipated patient, usually shows a megarecto-sigmoid with dilatation of the colon all the way down to the level of the levator mechanism (Fig. 32.1). There is usually a dramatic size discrepancy between a normal transverse and descending colon and the very dilated megarectosigmoid. The size of the colon guides the dosing of the laxatives, and it seems that the more localized the dilatation of the rectosigmoid, the better the results of a sigmoid resection. The contrast study may show an absence of the rectosigmoid (Fig. 32.2), which may have been resected during the original operation, and correlates with hypermotility and usually fecal incontinence.

Some clinicans use rectal and colonic manometry in the evaluation of these patients; however, more objective techniques are needed. Manometry is performed by placing balloons at different levels of the colon and recording the waves of contraction [3] or the electrical activity [4]. Scintigraphy, a nuclear medicine tool, is also being used to assess colonic motility [5]. These are sophisticated tools but at present, their help as guides for therapeutic decisions is lacking. The key information the surgeon needs is to know if and where a colonic resection would provide benefit to the patient. Histologic studies of the colon in these patients mainly show hypertrophic smooth muscle in the area of the dilated colon and normal ganglion cells, but more sophisticated histopathologic investigations will hopefully soon yield results. Further investigations in this area will enhance our knowledge about colonic dysmotility in this patients, and thereby guide therapy.

Constipation Prescription

Constipation Prescription

Did you ever think feeling angry and irritable could be a symptom of constipation? A horrible fullness and pressing sharp pains against the bladders can’t help but affect your mood. Sometimes you just want everyone to leave you alone and sleep to escape the pain. It is virtually impossible to be constipated and keep a sunny disposition. Follow the steps in this guide to alleviate constipation and lead a happier healthy life.

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