Constipation in children
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《美国医学杂志》
Indiana University School of Medicine, James Whitcomb Riley Hospital for Children, Indianapolis, Indiana, USA
Abstract
Constipation is a common problem throughout the world. It occurs in about 10-20% of adults in Western Countries and 0.3% to 28% of children worldwide. Most childhood constipation results from intentional withholding of stool following a painful experience with defecation. Thus, an extensive evaluation is often not necessary in a child presenting with constipation. Treatment should include education, evacuation of the rectum with oral or rectal laxatives if an impaction is present, laxatives to ensure soft stools and behavior modification.
Keywords: Constipation; Fecal retention; Encopresis
Constipation is a common problem throughout the world. It occurs in both adults and children. In the United States, 3 % of visits to a pediatrician and 25% of visits to a pediatric gastroenterologist are for problems related to constipation and 34% of British children aged 4 to 11 years have experienced constipation.[1], [2]
Definition
Constipation is a symptom, not a disease or a sign. For this reason, a precise definition has been elusive. Constipation has a different meaning for different people and often reflects an individual's view of what the normal pattern of defecation should be. Thus, its definition has included terms such as difficult or infrequent bowel movements, painful defecation, passage of hard stools and a sensation of incomplete evacuation of stool. The practice guidelines of the North American Society for Pediatric Gastroenterology Hepatology and Nutrition (NASPGHAN) defined constipation in children as a delay or difficulty in defecation, present for 2 or more weeks and sufficient to cause significant distress to the patient.[3] Recently, a group of pediatric gastroenterologists and pediatricians meeting in Paris to seek a consensus on terminology for childhood constipation defined chronic constipation as 2 or more of the following occurring over the preceding 8 weeks: Frequency of bowel movements less than 3 per week, more than 1 episode of fecal incontinence per week, large stools in the rectum or palpable on abdominal examination, passing of stools so large that they obstruct the toilet, retentive posturing and withholding behavior, and painful defecation.[4]
Epidemiology
The exact worldwide prevalence of constipation in children is not known. Population-based studies suggest that 10-20% of adults in Western Countries and in Asia have one or more symptoms of constipation.[5],[6] and it is estimated that 0.3% to 28% of children worldwide are constipated.[2] Constipation occurs in all social classes. Contrary to adults where it is much more common in females, childhood constipation probably occurs much more commonly in boys than in girls.[7]
Physiology of defecation
The normal process of fecal evacuation begins with propulsion of the fecal matter through the colon. This is accomplished by high amplitude propagated contractions (HAPCs) that occur several times during the day, occurring more frequently in infants and decreasing to 2-4 per day in adults. In addition to the high amplitude contractions, an increase in motility of the colon following a meal, the gastrocolic reflex, also helps to propel stool along the colon to the rectum, where it is stored until appropriate conditions are present for voluntary evacuation. At the rectum, the mechanism for storage and evacuation of the fecal material is a complex process involving the puborectalis muscle, the detrussor muscles of the rectum and the autonomic and somatic nervous systems. The puborectalis muscle embraces the rectal neck and forms an angle, the anorectal angle, with the internal and external anal sphincters surrounding the anal canal. This angle, at rest, is 85-105° and supports much of the weight of the fecal mass in the rectum, relieving the sphincters of the bulk of this pressure. Distension of the rectum causes a reflex relaxation of the internal anal sphincter and contraction of the rectal detrussor muscles. If defecation is desired, the puborectalis and levator ani muscles are relaxed, straightening the anorectal angle. Straining increases the intraabdominal pressure and results in evacuation of feces. If defecation is not desired, contraction of the external anal sphincter prevents fecal loss until the rectal wall adapts to the increasing volume.
Pathophysiology
Disruption of the normal physiology of defecation leads to constipation. Constipation may, therefore, result from defective or impaired propulsion, defective or impaired sensation or outlet obstruction table1.
Etiology
In about 95% of children with constipation, no obvious anatomic, biochemical or physiologic abnormalities are identified. Many of these children have functional constipation resulting from intentional withholding of stool. In such children, an unpleasant event may have been the precipitating factor for the desire to withhold stool. Borowitz and colleagues, in a recent study, found that painful defecation was the primary precipitant of constipation in early childhood.[8] A change from human milk to cow milk or from a cow milk base formula to a soy base formula may lead to firmer stools and hence painful defecation in an infant. Coercive or inappropriate toilet training in a toddler not ready for toilet training may lead to withholding of stool and eventual inevitable passage of dry hard stools with discomfort. Cow milk allergy may lead to hard stools, anal fissures and painful defecation.[9] In the older child, the tendency to withhold may develop from situations that make defecation uncomfortable or inconvenient such as unpleasant toilet facilities at school or anal pain resulting from streptococcal anusitis or sexual abuse. In all cases, fecal withholding beginning as a reaction to an acute process becomes a recurrent phenomenon that leads to a vicious cycle of withholding and evacuation of large, hard and painful stools.
Clinical presentation
The most common presentation of childhood constipation is infrequent bowel movements. Studies have shown that stool frequency decreases from 4 or more per day during infancy to about one per day at 4 years of age. Stool frequency of less than 3 times per week at any age is outside the norm. In addition to infrequent bowel movements, many children with constipation pass large, hard stools and display stool withholding behavior, characterized by stiffening of the whole body and screaming in infants, to walking on tiptoes, hanging on to furniture, tightening of the buttocks or hiding in corners in older children. Abdominal pain and overflow fecal incontinence (encopresis) may also be presenting symptoms in older children.
Evaluation
A careful history and physical examination will identify red flags table2 which may signal the probable presence of an organic cause for constipation and lead to appropriate testing. The history should include age of onset of symptoms; the infant who failed to pass meconium within the first 48 hours of life is more likely to have Hirschsprung's disease than the infant whose constipation began after being weaned from breast milk.[10] Other pertinent historical data to obtain include duration of symptoms; frequency of bowel movements; usual diet; presence of withholding behavior, fecal incontinence, abdominal pain, abdominal distention, vomiting, weight loss; family history of constipation, thyroid disease, celiac disease, Hirschsprung's disease or cystic fibrosis.
The physical examination should include all body systems so as to exclude any systemic illness complicated by constipation. Fecal masses are usually palpable in the suprapubic region and left lower quadrant of the abdomen in children with constipation. An occasional child has a massive fecal mass palpable from the hypogastrium to the level of the umbilicus; even in such children, abdominal distention is minimal if there is no anatomic obstruction because colonic gas is not retained with the feces. Anal examination may reveal perianal disease such as an anal fissure or anusitis. A digital rectal examination may reveal a tight anus suggesting the possibility of anal stenosis or Hirschsprung's disease if the child also has a distended abdomen and no stool in the rectum. A lax anus may be indicative of neurological disease.
Investigations
Since only about 5% of children with constipation have an organic etiology for their symptoms, most do not need any diagnostic test. A plain radiograph of the abdomen is useful in determining if a fecal impaction is present in a child who refuses a rectal examination and in the markedly obese child in whom a good rectal examination is technically challenging. In the child with severe constipation in whom Hirschsprung disease remains a diagnostic possibility, an unprepared barium enema or anorectal manometry are useful initial tests. The barium enema in an unprepared colon will demonstrate a transition from a dilated, stool-filled normal or ganglionic bowel to an empty abnormal or aganglionic bowel. The transition zone is better defined in an older child; it may not be seen in an infant because there has not been enough time to distend the normal portion of bowel with stool. A barium enema is also useful when other anatomic abnormalities such as a colonic or rectal stricture is suspected.
Anorectal manometry is a test which allows one to measure pressures in the anorectum. Distention of the rectum in a normal individual produces reflex relaxation of the internal anal sphincter (the rectoanal inhibitory reflex) Figure1. Absence of the rectoanal inhibitory reflex is suggestive of Hirschsprung's disease. Absence of the rectoanal inhibitory reflex is also seen in patients with internal anal sphincter achalasia.[11] In these patients, a rectal biopsy is normal despite a nonrelaxing internal anal sphincter. Other abnormalities, mostly functional, which may be diagnosed at anorectal manometry include abnormalities of rectal sensation, abnormalities of resting and squeeze pressures of the anus and pelvic floor dyssynergia (paradoxical contraction of the external anal sphincter during attempts at defecation).
A rectal biopsy provides histological information. Absence of submucosal ganglion cell in the presence of hyperplastic nerve trunks is diagnostic of Hirschsprung's disease. Hyperganglionosis and/or ectopic ganglion cells are features of the controversial disorder referred to as neuronal intestinal dysplasia.
A colonic transit study using radioopaque markers is useful in confirming constipation when there is no objective data to support the history. Pancolonic or segmental colonic transit abnormalities can be detected with this test. The patient ingests radioopaque markers daily for 6 days and a plain abdominal radiograph is obtained on the 7th day. The total transit and segmental transit times are determined by counting the number of markers in the entire colon or the segment of interest, multiplying that by 24 hours and dividing by the total number of markers ingested. Normal values for children are available.[12]
Colonic manometry is a more sophisticated way of studying colonic motility. A water-perfused or solid-state catheter with pressure sensors placed at various lengths of the catheter is placed in the colon during colonoscopy. The study is performed over several hours. Recordings of colonic motility during fasting, postprandial and post-colonic stimulation with a colon stimulant are obtained. Normal colonic motility is characterized by the presence of HAPCs and increased colonic motility following a meal. A myopathy is characterized by absence of colonic contractions or weak colonic contractions while a neuropathy is characterized by disordered and nonpropagating high amplitude contractions or an absence of the gastrocolic response.[13]
Treatment
Patients with an identifiable organic cause for constipation should have the underlying cause appropriately treated medically or surgically. For children with acute onset constipation, dietary measures including an increase in fluid and carbohydrate intake often resolves the problem. There may be a role for increased dietary fiber if the diet is deficient.[14] Normal intake should be at least the patient's age in year + 5 gm per day. In the child with a clear history of intentional fecal withholding, the treatment is 3-fold and should begin with education. This implies explaining to the child and parents why withholding stool leads to a vicious cycle of constipation with or without fecal incontinence. When stool is retained for long periods of time in the rectum, water is reabsorbed, leading to an accumulation of desiccated stool which is usually painful to evacuate. When a large amount of desiccated stool is retained in the rectum, the anus loses resting tone resulting in incontinence of small amounts of fresh stool reaching the rectum. After education, any fecal impaction in the rectum should be removed with oral or rectal laxatives table3. Occasionally, a child with a massive rectal impaction requires manual disimpaction under anesthesia. A laxative should then be prescribed at appropriate doses to ensure evacuation of soft stools. The third and perhaps the most important aspect of the treatment is a behavior modification program. The child should be encouraged to sit on the toilet and evacuate at specific times during the day so as to establish a regular pattern of defecation. Sitting after meals is recommended so as to take advantage of the gastro-colic reflex. Rewarding success is helpful particularly in the difficult child. The process of establishing a regular bowel habit may take several months and laxatives may need to be continued for the length of time it takes to establish such a bowel habit.[3] After a regular bowel habit is established and the patient is no longer withholding stool, the laxative should be gradually weaned and the patient transitioned to dietary management with emphasis on a balanced diet that includes an adequate amount of fiber and adequate amount of fluid intake.
Other treatments
In a selective number of patients with recalcitrant functional constipation who are found at anorectal manometry to have pelvic floor dyssynergia anorectal biofeedback training may be beneficial.[15] This therapy is based on the principle of learning through reinforcement. The patient is allowed to observe his/her abnormal manometric tracing during simulated defecation; he or she is then encouraged to correct the abnormality using the dynamic manometric tracing for visual feedback. Some difficult patients with or without abnormalities on a colonic motility study may benefit from surgery[16] including resection of an abnormal left colon and appendicocecostomy to provide access for daily antegrade enemas.
References
1. Loening-Baucke V. Chronic constipation in children. Gastroenterology 1993; 105 : 1557-1564.
2. Benninga MA, Voskuijl WP, Taminiau JA. Childhood constipation: is there new light in the tunnel J Pediatr Gastroenterol Nutr 2004; 39 : 448-464.
3. Baker SS, Liptak GS, Colletti RB et al. Constipation in infants and children: evaluation and treatment. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition. [erratum appears in J Pediatr Gastroenterol Nutr 2000 Jan;30(1):109]. J Pediatr Gastroenterol Nutr 1999; 29 : 612-626.
4. Benninga M, Candy DC, Catto-Smith AG et al. The Paris Consensus on Childhood Constipation Terminology (PACCT) Group. J Pediatr Gastroenterol Nutr 2005; 40 : 273-275.
5. Talley NJ, Weaver AL, Zinsmeister AR, Melton LJ, 3rd. Functional constipation and outlet delay: a population-based study. Gastroenterology 1993; 105 : 781-790.
6. Cheng C, Chan AO, Hui WM, Lam SK. Coping strategies, illness perception, anxiety and depression of patients with idiopathic constipation: a population-based study. Aliment Pharmacol Ther 2003; 18 : 319-326.
7. Di Lorenzo C. Pediatric anorectal disorders. In: Rao SSC ed. Gastroenterology Clinics of North America "Disorders of the Anorectum". Philadelphia; W.B. Saunders, PA, 2001; 30 : 269-287.
8. Borowitz SM, Cox DJ, Tam A, Ritterband LM, Sutphen JL, Penberthy JK. Precipitants of constipation during early childhood. J Am Board Fam Pract 2003; 16 : 213-218.
9. Iacono G, Cavataio F, Montalto G et al. A. Intolerance of cow's milk and chronic constipation in children. New Engl J Med 1998; 339 : 1100-1104.
10. Swenson O, Sherman JO, Fisher JH. Diagnosis of congenital megacolon: an analysis of 501 patients. J Pediatr Surg 1973; 8: 587-594.
11. Messineo A, Codrich D, Monai M, Martellossi S, Ventura A. The treatment of internal anal sphincter achalasia with botulinum toxin. Pediatr Surg Internat 2001; 17 : 521-523.
12. Wagener S, Shankar KR, Turnock RR, Lamont GL, Baillie CT. Colonic transit time-what is normal J Pediatr Surg 2004; 39 : 166-169; discussion 166-169.
13. Di Lorenzo C, Hillemeier C, Hyman P et al. Manometry studies in children: minimum standards for procedures. Neurogastroenterol Motility 2002; 14 : 411-420.
14. Loening-Baucke V, Miele E, Staiano A. Fiber (glucomannan) is beneficial in the treatment of childhood constipation. Pediatrics 2004; 113 : e259-264.
15. Croffie JM, Ammar MS, Pfefferkorn MD et al. Assessment of the effectiveness of biofeedback in children with dyssynergic defecation and recalcitrant constipation/encopresis: does home biofeedback improve long-term outcomes. Clin Pediatr 2005; 44 : 63-71.
16. Youssef NN, Pensabene L, Barksdale E, Jr., Di Lorenzo C. Is there a role for surgery beyond colonic aganglionosis and anorectal malformations in children with intractable constipation J Pediatr Surg 2004; 39 : 73-77.(Croffie Joseph M)
Abstract
Constipation is a common problem throughout the world. It occurs in about 10-20% of adults in Western Countries and 0.3% to 28% of children worldwide. Most childhood constipation results from intentional withholding of stool following a painful experience with defecation. Thus, an extensive evaluation is often not necessary in a child presenting with constipation. Treatment should include education, evacuation of the rectum with oral or rectal laxatives if an impaction is present, laxatives to ensure soft stools and behavior modification.
Keywords: Constipation; Fecal retention; Encopresis
Constipation is a common problem throughout the world. It occurs in both adults and children. In the United States, 3 % of visits to a pediatrician and 25% of visits to a pediatric gastroenterologist are for problems related to constipation and 34% of British children aged 4 to 11 years have experienced constipation.[1], [2]
Definition
Constipation is a symptom, not a disease or a sign. For this reason, a precise definition has been elusive. Constipation has a different meaning for different people and often reflects an individual's view of what the normal pattern of defecation should be. Thus, its definition has included terms such as difficult or infrequent bowel movements, painful defecation, passage of hard stools and a sensation of incomplete evacuation of stool. The practice guidelines of the North American Society for Pediatric Gastroenterology Hepatology and Nutrition (NASPGHAN) defined constipation in children as a delay or difficulty in defecation, present for 2 or more weeks and sufficient to cause significant distress to the patient.[3] Recently, a group of pediatric gastroenterologists and pediatricians meeting in Paris to seek a consensus on terminology for childhood constipation defined chronic constipation as 2 or more of the following occurring over the preceding 8 weeks: Frequency of bowel movements less than 3 per week, more than 1 episode of fecal incontinence per week, large stools in the rectum or palpable on abdominal examination, passing of stools so large that they obstruct the toilet, retentive posturing and withholding behavior, and painful defecation.[4]
Epidemiology
The exact worldwide prevalence of constipation in children is not known. Population-based studies suggest that 10-20% of adults in Western Countries and in Asia have one or more symptoms of constipation.[5],[6] and it is estimated that 0.3% to 28% of children worldwide are constipated.[2] Constipation occurs in all social classes. Contrary to adults where it is much more common in females, childhood constipation probably occurs much more commonly in boys than in girls.[7]
Physiology of defecation
The normal process of fecal evacuation begins with propulsion of the fecal matter through the colon. This is accomplished by high amplitude propagated contractions (HAPCs) that occur several times during the day, occurring more frequently in infants and decreasing to 2-4 per day in adults. In addition to the high amplitude contractions, an increase in motility of the colon following a meal, the gastrocolic reflex, also helps to propel stool along the colon to the rectum, where it is stored until appropriate conditions are present for voluntary evacuation. At the rectum, the mechanism for storage and evacuation of the fecal material is a complex process involving the puborectalis muscle, the detrussor muscles of the rectum and the autonomic and somatic nervous systems. The puborectalis muscle embraces the rectal neck and forms an angle, the anorectal angle, with the internal and external anal sphincters surrounding the anal canal. This angle, at rest, is 85-105° and supports much of the weight of the fecal mass in the rectum, relieving the sphincters of the bulk of this pressure. Distension of the rectum causes a reflex relaxation of the internal anal sphincter and contraction of the rectal detrussor muscles. If defecation is desired, the puborectalis and levator ani muscles are relaxed, straightening the anorectal angle. Straining increases the intraabdominal pressure and results in evacuation of feces. If defecation is not desired, contraction of the external anal sphincter prevents fecal loss until the rectal wall adapts to the increasing volume.
Pathophysiology
Disruption of the normal physiology of defecation leads to constipation. Constipation may, therefore, result from defective or impaired propulsion, defective or impaired sensation or outlet obstruction table1.
Etiology
In about 95% of children with constipation, no obvious anatomic, biochemical or physiologic abnormalities are identified. Many of these children have functional constipation resulting from intentional withholding of stool. In such children, an unpleasant event may have been the precipitating factor for the desire to withhold stool. Borowitz and colleagues, in a recent study, found that painful defecation was the primary precipitant of constipation in early childhood.[8] A change from human milk to cow milk or from a cow milk base formula to a soy base formula may lead to firmer stools and hence painful defecation in an infant. Coercive or inappropriate toilet training in a toddler not ready for toilet training may lead to withholding of stool and eventual inevitable passage of dry hard stools with discomfort. Cow milk allergy may lead to hard stools, anal fissures and painful defecation.[9] In the older child, the tendency to withhold may develop from situations that make defecation uncomfortable or inconvenient such as unpleasant toilet facilities at school or anal pain resulting from streptococcal anusitis or sexual abuse. In all cases, fecal withholding beginning as a reaction to an acute process becomes a recurrent phenomenon that leads to a vicious cycle of withholding and evacuation of large, hard and painful stools.
Clinical presentation
The most common presentation of childhood constipation is infrequent bowel movements. Studies have shown that stool frequency decreases from 4 or more per day during infancy to about one per day at 4 years of age. Stool frequency of less than 3 times per week at any age is outside the norm. In addition to infrequent bowel movements, many children with constipation pass large, hard stools and display stool withholding behavior, characterized by stiffening of the whole body and screaming in infants, to walking on tiptoes, hanging on to furniture, tightening of the buttocks or hiding in corners in older children. Abdominal pain and overflow fecal incontinence (encopresis) may also be presenting symptoms in older children.
Evaluation
A careful history and physical examination will identify red flags table2 which may signal the probable presence of an organic cause for constipation and lead to appropriate testing. The history should include age of onset of symptoms; the infant who failed to pass meconium within the first 48 hours of life is more likely to have Hirschsprung's disease than the infant whose constipation began after being weaned from breast milk.[10] Other pertinent historical data to obtain include duration of symptoms; frequency of bowel movements; usual diet; presence of withholding behavior, fecal incontinence, abdominal pain, abdominal distention, vomiting, weight loss; family history of constipation, thyroid disease, celiac disease, Hirschsprung's disease or cystic fibrosis.
The physical examination should include all body systems so as to exclude any systemic illness complicated by constipation. Fecal masses are usually palpable in the suprapubic region and left lower quadrant of the abdomen in children with constipation. An occasional child has a massive fecal mass palpable from the hypogastrium to the level of the umbilicus; even in such children, abdominal distention is minimal if there is no anatomic obstruction because colonic gas is not retained with the feces. Anal examination may reveal perianal disease such as an anal fissure or anusitis. A digital rectal examination may reveal a tight anus suggesting the possibility of anal stenosis or Hirschsprung's disease if the child also has a distended abdomen and no stool in the rectum. A lax anus may be indicative of neurological disease.
Investigations
Since only about 5% of children with constipation have an organic etiology for their symptoms, most do not need any diagnostic test. A plain radiograph of the abdomen is useful in determining if a fecal impaction is present in a child who refuses a rectal examination and in the markedly obese child in whom a good rectal examination is technically challenging. In the child with severe constipation in whom Hirschsprung disease remains a diagnostic possibility, an unprepared barium enema or anorectal manometry are useful initial tests. The barium enema in an unprepared colon will demonstrate a transition from a dilated, stool-filled normal or ganglionic bowel to an empty abnormal or aganglionic bowel. The transition zone is better defined in an older child; it may not be seen in an infant because there has not been enough time to distend the normal portion of bowel with stool. A barium enema is also useful when other anatomic abnormalities such as a colonic or rectal stricture is suspected.
Anorectal manometry is a test which allows one to measure pressures in the anorectum. Distention of the rectum in a normal individual produces reflex relaxation of the internal anal sphincter (the rectoanal inhibitory reflex) Figure1. Absence of the rectoanal inhibitory reflex is suggestive of Hirschsprung's disease. Absence of the rectoanal inhibitory reflex is also seen in patients with internal anal sphincter achalasia.[11] In these patients, a rectal biopsy is normal despite a nonrelaxing internal anal sphincter. Other abnormalities, mostly functional, which may be diagnosed at anorectal manometry include abnormalities of rectal sensation, abnormalities of resting and squeeze pressures of the anus and pelvic floor dyssynergia (paradoxical contraction of the external anal sphincter during attempts at defecation).
A rectal biopsy provides histological information. Absence of submucosal ganglion cell in the presence of hyperplastic nerve trunks is diagnostic of Hirschsprung's disease. Hyperganglionosis and/or ectopic ganglion cells are features of the controversial disorder referred to as neuronal intestinal dysplasia.
A colonic transit study using radioopaque markers is useful in confirming constipation when there is no objective data to support the history. Pancolonic or segmental colonic transit abnormalities can be detected with this test. The patient ingests radioopaque markers daily for 6 days and a plain abdominal radiograph is obtained on the 7th day. The total transit and segmental transit times are determined by counting the number of markers in the entire colon or the segment of interest, multiplying that by 24 hours and dividing by the total number of markers ingested. Normal values for children are available.[12]
Colonic manometry is a more sophisticated way of studying colonic motility. A water-perfused or solid-state catheter with pressure sensors placed at various lengths of the catheter is placed in the colon during colonoscopy. The study is performed over several hours. Recordings of colonic motility during fasting, postprandial and post-colonic stimulation with a colon stimulant are obtained. Normal colonic motility is characterized by the presence of HAPCs and increased colonic motility following a meal. A myopathy is characterized by absence of colonic contractions or weak colonic contractions while a neuropathy is characterized by disordered and nonpropagating high amplitude contractions or an absence of the gastrocolic response.[13]
Treatment
Patients with an identifiable organic cause for constipation should have the underlying cause appropriately treated medically or surgically. For children with acute onset constipation, dietary measures including an increase in fluid and carbohydrate intake often resolves the problem. There may be a role for increased dietary fiber if the diet is deficient.[14] Normal intake should be at least the patient's age in year + 5 gm per day. In the child with a clear history of intentional fecal withholding, the treatment is 3-fold and should begin with education. This implies explaining to the child and parents why withholding stool leads to a vicious cycle of constipation with or without fecal incontinence. When stool is retained for long periods of time in the rectum, water is reabsorbed, leading to an accumulation of desiccated stool which is usually painful to evacuate. When a large amount of desiccated stool is retained in the rectum, the anus loses resting tone resulting in incontinence of small amounts of fresh stool reaching the rectum. After education, any fecal impaction in the rectum should be removed with oral or rectal laxatives table3. Occasionally, a child with a massive rectal impaction requires manual disimpaction under anesthesia. A laxative should then be prescribed at appropriate doses to ensure evacuation of soft stools. The third and perhaps the most important aspect of the treatment is a behavior modification program. The child should be encouraged to sit on the toilet and evacuate at specific times during the day so as to establish a regular pattern of defecation. Sitting after meals is recommended so as to take advantage of the gastro-colic reflex. Rewarding success is helpful particularly in the difficult child. The process of establishing a regular bowel habit may take several months and laxatives may need to be continued for the length of time it takes to establish such a bowel habit.[3] After a regular bowel habit is established and the patient is no longer withholding stool, the laxative should be gradually weaned and the patient transitioned to dietary management with emphasis on a balanced diet that includes an adequate amount of fiber and adequate amount of fluid intake.
Other treatments
In a selective number of patients with recalcitrant functional constipation who are found at anorectal manometry to have pelvic floor dyssynergia anorectal biofeedback training may be beneficial.[15] This therapy is based on the principle of learning through reinforcement. The patient is allowed to observe his/her abnormal manometric tracing during simulated defecation; he or she is then encouraged to correct the abnormality using the dynamic manometric tracing for visual feedback. Some difficult patients with or without abnormalities on a colonic motility study may benefit from surgery[16] including resection of an abnormal left colon and appendicocecostomy to provide access for daily antegrade enemas.
References
1. Loening-Baucke V. Chronic constipation in children. Gastroenterology 1993; 105 : 1557-1564.
2. Benninga MA, Voskuijl WP, Taminiau JA. Childhood constipation: is there new light in the tunnel J Pediatr Gastroenterol Nutr 2004; 39 : 448-464.
3. Baker SS, Liptak GS, Colletti RB et al. Constipation in infants and children: evaluation and treatment. A medical position statement of the North American Society for Pediatric Gastroenterology and Nutrition. [erratum appears in J Pediatr Gastroenterol Nutr 2000 Jan;30(1):109]. J Pediatr Gastroenterol Nutr 1999; 29 : 612-626.
4. Benninga M, Candy DC, Catto-Smith AG et al. The Paris Consensus on Childhood Constipation Terminology (PACCT) Group. J Pediatr Gastroenterol Nutr 2005; 40 : 273-275.
5. Talley NJ, Weaver AL, Zinsmeister AR, Melton LJ, 3rd. Functional constipation and outlet delay: a population-based study. Gastroenterology 1993; 105 : 781-790.
6. Cheng C, Chan AO, Hui WM, Lam SK. Coping strategies, illness perception, anxiety and depression of patients with idiopathic constipation: a population-based study. Aliment Pharmacol Ther 2003; 18 : 319-326.
7. Di Lorenzo C. Pediatric anorectal disorders. In: Rao SSC ed. Gastroenterology Clinics of North America "Disorders of the Anorectum". Philadelphia; W.B. Saunders, PA, 2001; 30 : 269-287.
8. Borowitz SM, Cox DJ, Tam A, Ritterband LM, Sutphen JL, Penberthy JK. Precipitants of constipation during early childhood. J Am Board Fam Pract 2003; 16 : 213-218.
9. Iacono G, Cavataio F, Montalto G et al. A. Intolerance of cow's milk and chronic constipation in children. New Engl J Med 1998; 339 : 1100-1104.
10. Swenson O, Sherman JO, Fisher JH. Diagnosis of congenital megacolon: an analysis of 501 patients. J Pediatr Surg 1973; 8: 587-594.
11. Messineo A, Codrich D, Monai M, Martellossi S, Ventura A. The treatment of internal anal sphincter achalasia with botulinum toxin. Pediatr Surg Internat 2001; 17 : 521-523.
12. Wagener S, Shankar KR, Turnock RR, Lamont GL, Baillie CT. Colonic transit time-what is normal J Pediatr Surg 2004; 39 : 166-169; discussion 166-169.
13. Di Lorenzo C, Hillemeier C, Hyman P et al. Manometry studies in children: minimum standards for procedures. Neurogastroenterol Motility 2002; 14 : 411-420.
14. Loening-Baucke V, Miele E, Staiano A. Fiber (glucomannan) is beneficial in the treatment of childhood constipation. Pediatrics 2004; 113 : e259-264.
15. Croffie JM, Ammar MS, Pfefferkorn MD et al. Assessment of the effectiveness of biofeedback in children with dyssynergic defecation and recalcitrant constipation/encopresis: does home biofeedback improve long-term outcomes. Clin Pediatr 2005; 44 : 63-71.
16. Youssef NN, Pensabene L, Barksdale E, Jr., Di Lorenzo C. Is there a role for surgery beyond colonic aganglionosis and anorectal malformations in children with intractable constipation J Pediatr Surg 2004; 39 : 73-77.(Croffie Joseph M)