eMedicine Specialties > Pediatrics: Surgery > General Surgery

Constipation and Bowel Management

Author: Marc A Levitt, MD, Associate Professor of Surgery, University of Cincinnati; Associate Director, Colorectal Center for Children, Department of Pediatric Surgery, Cincinnati Children's Hospital Medical Center
Coauthor(s): Alberto Pena, MD, Consulting Surgeon, Colorectal Center for Children, Department of Pediatric Surgery, Cincinnati Children's Hospital Medical Center
Contributor Information and Disclosures

Updated: Feb 19, 2010

Introduction

Constipation is an extremely common problem in the pediatric population. Most patients can be treated with mild measures such as dietary changes and laxatives. However, a significant group of patients has severe constipation and require more aggressive treatments, which can be described as bowel management. Most of these patients have idiopathic constipation, which is associated with a wide spectrum of severity. A small group of these patients have very severe bowel dysmotility and overlap with the group of patients considered to have intestinal pseudo-obstruction.

In addition to the idiopathic group, patients who have undergone surgery for anorectal malformations, as well as patients with Hirschsprung disease, can suffer from severe constipation and incontinence. If the patient is not toilet trained by age 3 years, the clinician should offer an artificial way to keep the patient clean and socially acceptable. This regimen essentially involves teaching the family and patient how to clean the colon once a day with an enema and to manipulate the colonic motility with diet, medications, or both when necessary to ensure that the patient does not pass stool between enemas. Management of patients with these surgical problems has greatly informed care of patients with idiopathic constipation.

Understanding the difference between fecal incontinence and overflow pseudoincontinence is vital; the latter is a sequela of a severe inertia of the rectosigmoid. Fecal incontinence requires a bowel management regimen, which involves daily enemas because such patients are unable to voluntarily empty their colons. Patients with incontinence due to severe constipation may have overflow pseudoincontinence. Once their constipation is managed, they may be able to have voluntary bowel movements. Such patients require a bowel management regimen that involves laxatives, which help them regularly and voluntarily empty their colon. Understanding this clinical difference is vital because management of these 2 types of patients is significantly different.

Medical treatment with enemas, laxatives, and medications has traditionally been used in these patients with varying success. These treatments are often used without a specific rationale in an indiscriminate manner and often reflect the lack of understanding of the difference between patients with overflow pseudoincontinence and those with real fecal incontinence. Bowel management with an organized protocol that is implemented by a thoughtful team of physicians and nurses can have a dramatic impact on a patient with fecal incontinence. Likewise, bowel management in a patient with overflow pseudoincontinence can treat the impaction, avoid constipation, and allow fecally continence.

Pathophysiology

Bowel motility is one of the most complex and sophisticated functions in the human body. The colon absorbs water and functions as a reservoir. Liquid waste delivered by the small bowel into the cecum becomes solid stool in the descending and sigmoid colon. The colon has a slow motility; its peristalsis seems to be less active in the distal portions of the colon. Every 24-48 hours, the rectosigmoid develops active peristaltic waves that indicate that it must be emptied. This is perceived by the individual, who then has the capacity to voluntarily retain the stool up to a point or to empty it, depending on social circumstances.

To achieve fecal continence, 3 components are necessary: sensation within the rectum, good motility of the colon, and good voluntary muscle or sphincter control. Children who have anorectal malformations lack all or some of these essential components. Children who have had surgery for Hirschsprung disease may have lost some of these components because of their pelvic surgery.

All patients born with anorectal malformations (except those with pure rectal atresia, which is rare) are missing the anal canal; thus, they do not experience the exquisite sensation in this area that is very important for continence. They lack the intrinsic sensation associated with stool or gas passing through the rectum. Therefore, the child may unknowingly soil.

Distension of the rectum in a child with an anorectal malformation, in whom the rectum has been correctly placed within the sphincter mechanism, stretches the voluntary muscles that surround the rectum and gives the child proprioception, which is another vital component of continence. The sphincter mechanism in children with imperforate anus widely varies among patients. The spectrum ranges from a mechanism similar to that observed in a child with bowel continence to a near total absence of muscles in the perineum. These muscles allow for good control and retention of stool.

The postoperative problems that occur in patients who undergo operations for imperforate anus or Hirschsprung disease do not have a defined pathophysiology. The type of repair that is performed clearly contributes to future complications. In patients with anorectal malformations, the presence of a preserved rectal reservoir plays a pivotal role. Poorly developed muscles, which are often associated with a hypodeveloped sacrum, and/or spinal and vertebral problems (eg, hemivertebrae, tethered cord, myelomeningocele), clearly contribute to the potential for fecal and urinary continence.

Normally, the rectosigmoid remains quiet for periods of 24-48 hours. A massive peristaltic wave then occurs, which allows complete emptying of the colon. Patients with anorectal malformations and Hirschsprung disease have abnormal peristaltic waves in the colon, which result in stagnant stool or an overactive colon. The child then develops constipation or encopresis (overflow incontinence). Alternatively, a very active colon may provoke a constant passing of stool, which may significantly interfere with bowel continence.

Idiopathic constipation is an inability or difficulty in regularly and efficiently passing stool. The etiology of this condition is unknown. It is by far the most common defecation disorder and the most common colonic motility disorder in children. Idiopathic constipation affects an enormous pediatric population and represents a very common cause for surgical consultation. It is relevant, not only because it affects millions of patients, but also because it is extremely incapacitating in its most serious form. In fact, it produces a form of fecal incontinence known as encopresis or overflow pseudoincontinence. Also, the most serious type of constipation cannot be differentiated from a very serious motility disorder called intestinal pseudo-obstruction, which carries a significant mortality rate.

Even when the cause of this condition is unknown, the literature presents many potential causes for the disease, most of which have no solid scientific basis. Many publications discuss dietary disorders as a cause of constipation. Different types of food have either a laxative or constipating effect on the body. Diet is important to regulate colonic motility; however, the therapeutic value of the diet is negligible in the most serious forms of constipation. Thousands of patients with mild forms of constipation are successfully managed with diet. However, patients in whom surgery is indicated have a much more serious form of this condition that does not respond to dietary treatment.

Presentation

History

Imperforate anus

• Children with fecal incontinence after imperforate anus repair can be categorized into the following 2 well-defined groups, which require individualized treatment plans:
  • Children with constipation (ie, slow motility) after imperforate anus repair have usually undergone a procedure in which the rectum was preserved (eg, anoplasty, posterior sagittal anorectoplasty, sacroperineal pull-through procedure). The vast majority of patients are included in this category.
  • Children with a tendency to have diarrhea (ie, fast motility) after imperforate anus repair have usually undergone a procedure in which the rectum and, sometimes, the sigmoid colon was resected (eg, abdominoperineal pull-through procedures, endorectal resections). Occasionally, the child has lost a portion of the colon for some other reason or has a condition that produces diarrhea.
• The patient's capacity for fecal continence (ie, the ability to hold stool voluntarily) varies according to the type of anorectal malformation with which the patient was born. High malformations are often accompanied by poor muscles, whereas low malformations are usually associated with good muscles. The degree of hypodevelopment of the sacrum and the presence of associated spinal anomalies contribute to the degree of fecal continence. For instance, a child with a high anomaly and near-normal muscles, sacrum, and spine has a good chance of achieving fecal continence, although this combination is rare.

Hirschsprung disease

Children who have undergone surgery for Hirschsprung disease often have postoperative constipation. A small group of patients have fecal incontinence as sequelae of the original pelvic operation, which usually manifests as constipation with the inability to voluntarily empty their colon.

Idiopathic constipation

Idiopathic constipation is a self-perpetuating and self-aggravating disease. A patient that has a certain degree of constipation that is not adequately treated only partially empties the colon throughout life, leaving larger and larger amounts of stool inside the rectosigmoid, which results in greater degrees of megasigmoid. Most surgeons accept the common clinical fact that the dilatation of a hollow viscus produces poor peristalsis. That explains why constipation means fecal retention, which produces megacolon that exacerbates the constipation. In addition, the passage of large, hard pieces of stool may produce painful anal lacerations (fissures), which result in a reluctance by the patient to have bowel movements. Consequently, if the patient was born with a certain degree of constipation and does not receive proper treatment, the constipation worsens and becomes an increasingly serious problem.

The condition is mostly incurable, which means that these patients must be monitored for life. Treatments are frequently administered on a temporary basis; they are then tapered or interrupted, followed by a subsequent recurrence. This creates a great deal of frustration for patients and parents and may contribute to the well-known pattern of patients who seek a solution from many different doctors or clinics.

Another controversy involves symptom onset. Many doctors believe that this problem starts during the toilet-training process. Although symptoms become more evident at that time, the motility disorder is present at birth. Babies who are breastfed may not show symptoms due to the well-known laxative effect of human breast milk. When breastfeeding is discontinued and the patient receives formula and other foods, the symptoms become obvious. If the baby has constipation problems while breastfeeding, the patient likely has severe constipation that will exacerbate over time.

Many times, parents report that symptoms began when the patient was preschool aged. However, specific inquiries regarding bowel movement patterns since birth often reveal that the constipation started very early in life. Actually, the parents remember most vividly the episode of the first fecal impaction and refer to that event as the initiation of symptoms.

The definition of constipation is another problem. Many pediatricians believe that healthy individuals can go 2-3 days without a bowel movement throughout their lives without having any significant implications. That is, in fact, true for many individuals. However, when that principle is applied to a patient who has demonstrated idiopathic constipation, the concept interferes with an effective treatment and leads to the development of the vicious cycle described above.

Constipation in infants is manifested by difficult and sometimes painful bowel movements, the presence of hard stool, the passing of bloody-stained large pieces of stool, and periods of 2-3 days without passing stool. When these babies receive laxatives, the parents often have to increase the amount of laxatives administered to the point of producing diarrhea before the baby can pass stool. Even with liquid stool, parents describe that the babies are incapable of having bowel movements without some form of rectal stimulation.

The presence of a fissure is the first sign of trouble because it produces painful bowel movements, which tend to make the patient retain stool. Holding the stool for several days produces stool retention, which favors hardening of the stool. However, the patient eventually passes a larger and harder piece of stool that reopens the fissure, creating a vicious cycle. Mild forms of this condition can usually be successfully treated by a pediatrician, who may prescribe a diet with a high content of fiber, foods that act as laxatives, or both. If the diet does not correct the problem, then the pediatrician usually prescribes stool softeners, active-ingredient laxatives, or both. Laxatives are usually administered in the recommended dosages, which are successful in many patients but not in all patients; this is understandable given the wide spectrum of severity in this condition.

Fecal impaction is a stressful event characterized by retained stool for several days, crampy abdominal pain, and, occasionally, tenesmus. A rectal examination discloses the presence of a large mass of rock-hard stool located very low in the rectum. When laxatives are prescribed to a patient with fecal impaction, the result is an exacerbation of the abdominal pain and, occasionally, vomiting. This is a consequence of an increased colonic peristalsis (produced by the laxative) acting against a colonic obstruction produced by the fecal impaction. Despite the impaction, the patient may pass liquid stool, which is a phenomenon known as paradoxical diarrhea; the liquid stool passes around the solid fecal matter, but the impaction persists.

Constipation is recognized and diagnosed by most practitioners upon learning that a patient has difficulty passing stool or that a patient has not passed stool in 1-3 days. Another form of constipation that is not recognized by most physicians is characterized by multiple bowel movements throughout day, consisting of very small amounts of stool. The stool is very sticky and thick and eventually becomes only a smearing or soiling of the underwear. This is also considered constipation.

Soiling of the underwear without the patient's awareness is an ominous sign of bad constipation. If a patient who should have achieved bowel control soils underwear day and night and does not have spontaneous bowel movements, they have a phenomenon known as encopresis. These patients behave as fecally incontinent individuals. The phenomenon is also called overflow pseudoincontinence. When the constipation is adequately treated, the great majority of these pseudoincontinent children regain complete bowel control.

Diagnosis is clinical. The symptoms described above are very reliable in establishing the diagnosis. In addition, if a patient presents with symptoms similar to those described above, idiopathic constipation is statistically likely. Patients with untreated Hirschsprung disease do not soil themselves; in addition, without surgical treatment, Hirschsprung disease may be fatal. Individuals who survive are frequently malnourished and have a history of enterocolitis. Patients with idiopathic constipation do not have real enterocolitis. They occasionally experience episodes of distention and vomiting, similar to what is observed in enterocolitis. However, they actually have fecal impaction and an added picture of viral gastroenteritis that causes severe, crampy, abdominal pain and diarrhea around the impaction. Patients with Hirschsprung disease who experience actual enterocolitis become extremely toxic and lethargic and may die.

Physical

• Physical examination may reveal a left lower quadrant mass, which represents a sigmoid colon filled with impacted stool. 
• Examination of the rectum is vital to determine impaction. Also, in patients who have undergone surgery, the clinician must rule out the presence of a postoperative stricture, which is particularly possible in patients who did not undergo postoperative rectal dilations. 
• The location and caliber of the anus should be evaluated. Patients with anorectal malformations may have an anteriorly placed anus that is incorrect. Previously undiagnosed rectovestibular or rectoperineal fistulae in female patients have been reported. Congenital anal or rectal stenosis, which is very rare, may not be detected in the newborn period.

Indications

Bowel management is indicated in patients with fecal incontinence after surgical repair of imperforate anus or Hirschsprung disease. It is also used in patients who are continent after surgical repair but suffer from constipation.

Surgical therapy is occasionally used (see Surgical Therapy).

The 2 types of surgery described for bowel management are colonic resection and access for retrograde enemas. Certain patients may be candidates for sigmoid resection. This surgery is indicated in a small subset of patients with massive dilatation of their rectosigmoid, in whom a bowel management regimen has been successful. The goal of the resection is to reduce the amount of laxatives required to empty the colon on a daily basis and to, therefore, improve the patient's quality of life.

Access for retrograde enemas is a surgical procedure used to change the route for enema administration. At a certain age, patients desire more independence for their enema administration and want to avoid the rectal route. The authors recommend an appendicostomy placed in the umbilicus, which allows the patient to administer the enemas themselves. It is only indicated once a successful bowel management regimen has been implemented. Other authors have used a right lower quadrant appendicostomy or a cecostomy tube for this purpose.¹

Contraindications

Patients in whom resective therapy is considered to assist with bowel management must be fecally continent with a bowel management regimen. Resection of part of the colon in a patient with fecal incontinence can worsen the condition from a tendency to form solid stool to a tendency to make loose stool. Patients with incontinence and loose stool are much harder to manage than those who can form solid stool. Therefore, sigmoid resection is only used in patients who can voluntarily empty their colon, albeit with massive doses of laxatives. These patients require much smaller doses of laxatives after the surgery.

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