Chronic Gastrointestinal Disorders

Harvey W. Aiges MD

INTRODUCTION

Chronic gastrointestinal complaints are a significant part of primary care pediatrics. Abdominal pain, diarrhea, constipation, reflux, and emesis are seen frequently. The pediatric primary care provider must determine whether symptoms are functional (nonorganic) or related to disease in the gastrointestinal tract (organic). This chapter provides information about diagnosis and management of common functional and organic gastrointestinal disorders seen in pediatrics, including irritable bowel syndrome (IBS; neonatal through adolescent presentations), constipation and encopresis, chronic and recurrent abdominal pain, gastroesophageal reflux disease (GERD), peptic ulcer disease, chronic diarrhea and malabsorption, and inflammatory bowel disease. The diagnosis and management of abdominal migraine are discussed in Chapter 51. Munchausen syndrome by proxy can also be the underlying cause of a gastrointestinal tract disorder; this problem is discussed in Chapter 23.

Meticulous history, physical examination, and evaluation of the child’s growth and development will usually help the pediatric clinician determine the etiology of symptoms, providing the data needed for developing an appropriate therapeutic plan.

Irritable Bowel Syndrome

Irritable bowel syndrome affects a very large number of children and adolescents, resulting in a dramatic amount of school absenteeism and a significant use of health care resources (Camilleri & Choi, 1997). IBS is a psychophysiologic disorder of disturbed bowel habits and abdominal pain in the absence of demonstrable organic disease.

PATHOLOGY

Mast cells are metachromatic cells found widely throughout the body, including the gastrointestinal tract, where they are found in mucosal tissue. Mast cells are, of course, involved in both allergenic and nonallergenic events that are associated with inflammation. In the gastrointestinal tract, mast cell degranulation can occur as an antigen-mediated event, in which an immunoglobulin E (IgE)-dependent hypersensitivity reaction occurs. Mast cell degranulation is in part what underpins some of the symptomatology of such disorders as IBS, gastroenteritis with or without Helicobacter pylori infection, Crohn’s disease (CD), and ulcerative colitis (UC) (Thomson & Walker-Smith, 1998).

Although the exact mechanisms of IBS have not been clarified, there has been a significant advance in understanding of the factors involved in producing the myriad symptoms of IBS. These factors include dysmotility, visceral hypersensitivity, smooth muscle abnormalities, and psychogenic reasons. Patients with IBS have a different myoelectrical rhythm, meaning that the action potential of the cells of the intestine differs from that of patients without IBS. This different “signature” allows for abnormal contractions of the bowel in response to various stimuli, such as intestinal hormones, foods, and neurotransmitter substances. Therefore, symptoms can be induced by a large number of endogenous and exogenous stimuli, including infections, medications, teething, and emotional stress.

Patients with IBS have visceral hypersensitivity, meaning that they experience the sensation of fullness and pain at smaller volumes of gas or stool than the general population. These children also have systemic smooth muscle abnormalities, with an abnormal response to urodynamic studies. These patients are also more likely to wheeze when stimulated. All of these abnormalities are associated with autonomic nervous system dysfunction with associated blood pressure and pulse changes. These pathologic sequelae help explain many of the clinical findings associated with IBS (Hanauer, 1996; Rasquin-Weber et al., 1999). Adult patients with IBS have a much higher chance of having a definable psychiatric diagnosis, usually chronic anxiety or depression, than the general population (Trikas et al., 1999). There is considerable evidence that adult patients with IBS also have issues with anger management (Trikas et al., 1999; Welgan, Meshkinpour, & Ma, 2000). Ali et al. (2000) reported that emotional abuse, self-blame, and self-silencing were commonly found in women with IBS.

EPIDEMIOLOGY

It has been estimated that between 22 and 30 million Americans have IBS (Hanauer, 1996). Many patients with IBS never come to medical attention; thus, exact figures of prevalence and incidence are not available. Because IBS is not a disease but a function of one’s own body makeup, it may affect patients throughout their lives (Rasquin-Weber et al., 1999). No cultural or socioeconomic factors seem to be involved, although upper middle class patients seem to seek medical attention more frequently for IBS than do lower socioeconomic groups (Hanauer, 1996; Everhart & Renault, 1991).

Other disorders are associated with IBS, at least in the older adolescent and adult patient. These include fibromyalgia, chronic fatigue syndrome, and temporomandibular disorder (Aaron, Burke, & Buchwald, 2000; Yunus, Inanici, Aldag, & Mangold, 2000). Locke, Zinsmeister, Talley, Fett, and Melton (2000) also describe analgesics and food sensitivities as risk factors in adulthood.

HISTORY AND PHYSICAL EXAMINATION

A child with IBS may have any or all of the age-related symptoms and signs of the disorder. Other topics related to chronic gastrointestinal problems in children, including constipation and recurrent abdominal pain, probably are part of the clinical spectrum of IBS. The following discussion presents findings associated with IBS by symptom and age range.

Stool retention (neonatal period): Infants may strain at stool. The physical examination is normal except for tight anal sphincter noted on rectal examination.
Colic (1–4 months): The definition of colic is prolonged crying without an obvious reason. IBS is the most common etiology of colic. Other causes of colic can include esophagitis secondary to gastroesophageal reflux (GER) and cow’s milk protein allergy, or it can be an early sign of increased spasticity, as seen in cerebral palsy.
Toddler’s diarrhea/chronic nonspecific diarrhea of childhood (6 months–3 years): Toddler’s diarrhea is frequent loose, pasty bowel movements (ie, 2–12 per day). Food particles are frequently visible in the stool. The first stool of the morning is usually the most formed, because it has remained in the rectal ampulla overnight, allowing for water resorption. Interestingly, this child does not awake during the night to have a bowel movement, as is often seen with organic etiologies. The salient point of toddler’s diarrhea is the strikingly normal appearance, physical examination, mood, appetite, and activity level of the child despite runny stools. The child’s growth and development are normal unless inappropriate dietary restrictions have been instituted by the provider or the parents. Flare-ups of toddler’s diarrhea may occur spontaneously, but they often follow a stress, such as an episode of gastroenteritis, use of antibiotics, or teething (Kneepkens & Hoekstra, 1996).
Constipation (3–10 years): Although constipation may occur at any age from birth on, the child with IBS most commonly has clinically significant constipation during this time period. The constipation may take the form of infrequent bowel movements, hard and small-volume bowel movements, or incomplete evacuation of stool produced. This latter occurrence is the hardest to diagnose. The constipation of IBS is considered to be secondary to the patient’s inherent dysmotility. The patient may have episodes of stress diarrhea coexisting with the constipation.
Recurrent abdominal pain (11–18 years): Recurrent abdominal pain and vague abdominal pain are well-described clinical entities in adolescents with IBS in whom periumbilical pain of a recurrent or vague nature is present (Hyams et al., 1996). They are far more common in females, usually near the time of menarche. The patient frequently has a history of normal, daily bowel movements but objectively has large amounts of colonic stool by physical examination or abdominal radiographs. This form of IBS often is associated with intermittent episodes of stress diarrhea (eg, loose bowel movements at the times of school examinations, conflicts with friends) (Thomson & Walker-Smith, 1998).
Adult form of IBS (adolescence to adulthood): The adult form of IBS, which can be seen as early as preadolescence, has all the gastrointestinal features of IBS, including abdominal pain, constipation, and diarrhea, and is associated with autonomic dysfunction. The patient may experience flushing, rapid changes in pulse and blood pressure (especially in response to cold liquid ingestion), headaches, insomnia, lower back pain, and palpitations. Females especially may complain of urinary frequency and urgency. Urodynamic studies are likely to be abnormal. All of these clinical findings are thought to be related to abnormal smooth muscle responsiveness.

DIAGNOSTIC CRITERIA

The diagnosis of IBS cannot be made by any specific test. However, the diagnosis is highly likely if the patient exhibits all of the following:

Chronic gastrointestinal symptoms with normal growth and development
Symptoms that are not nocturnal
Normal physical examination, including negative hemoccult test, blood tests (complete blood count [CBC], erythrocyte sedimentation rate [ESR], serum albumin, iron, total iron-binding capacity [TIBC], amylase, H. pylori), radiographs, endoscopies, and biopsies (when indicated)
Positive family history for IBS

DIAGNOSTIC STUDIES

Invasive studies, such as barium radiographs, esophagogastroduodenoscopy, and colonoscopy, may not be necessary if all other evaluations are normal. In cases in which the results are confusing, the history is unclear, or the growth and development are abnormal, a more complete evaluation will be necessary.

MANAGEMENT

The child with IBS should be seen by the provider every 6 months. This frequency will provide a sound framework for following growth and development while addressing any nutritional, psychosocial, or other concerns of the child and parents. This frequency will also allow for surveillance activities and wellness management, while supporting the development of relationship-centered care.

IBS is not an organic disease, and no specific therapies can cure it because it is a function of the patient’s own body makeup. The pediatric provider should direct all management and therapeutic plans toward patient and family education about IBS, helping them learn how to cope with the disorder, and giving symptomatic relief when possible. The primary care clinician’s role is critical to patient and family acceptance of the diagnosis. The practitioner can support them in their ability to handle the occasional pain and discomfort experienced with IBS.

Treatment for symptomatic relief may include the following:

For constipation, younger than 1 year: barley malt extract (Maltsupex); older than 1 year: docusate sodium (Colace) for hard stools, senna (Senokot) for difficulty in passing stools
For chronic diarrhea: Regular diet; avoidance of very cold liquids, excessive sweets, and chewing gum or
candies. The role of aspirin use is also possibly related to IBS symptomatology, but aspirin should be avoided in all children and adolescents in any case because of its relationship to the pathogenesis of Reye’s syndrome.
For alternating constipation and diarrhea: Fiber (Metamucil or Fibercon)
For abdominal pain: Treatment for underlying cause (eg, constipation)

The vast majority of children with IBS can be managed solely by the pediatric primary care provider. The provider should consult a pediatric gastroenterologist if endoscopy is needed, if the case is atypical, or if the parents need more reassurance. The provider should become concerned that the diagnosis of IBS is incorrect if the following occur:

Weight, height, and development slow or diminish.
Symptoms are nocturnal.
Blood is seen or found in the stool.
Stool has positive Wright stain or Charcot-Leyden crystals.
The ESR is elevated, or serum albumin level is low.

What to Tell Parents

Irritable bowel syndrome is not a psychosomatic illness but a true physiologic entity. IBS is not “all in their head.” IBS is part of the patient’s individual makeup, and symptoms may be intermittent and lifelong. The patient with IBS does not have organic disease; therefore, there are no dietary or activity restrictions.

The school may need to be made aware of special bathroom needs (especially in the child with chronic diarrhea). The provider may need to assist the family in acquiring these bathroom privileges.

Constipation and Encopresis

The pediatric primary care provider may see a large number of children with a complaint of constipation or encopresis. There are not clear definitions of these two entities in children. However, most people accept constipation as meaning infrequent bowel movements, hard stools, or pain or straining with bowel movements. Encopresis is a more confusing term, but it is generally accepted to mean passage of stool into underwear or clothing of children who are 4 years of age or older. In most cases, the term encopresis is used synonymously with fecal soiling or fecal incontinence. Encopresis may also be associated with urinary incontinence disorders. For more information about the diagnosis and management of this latter problem, the reader is referred to Chapter 63.

PATHOLOGY

After the neonatal period, the vast majority of children with constipation have simple constipation as a result of a functional dysmotility (IBS) or from voluntary withholding. The withholding may be a result of problems with toilet training or fear of defecation secondary to passage of a large or painful stool. If stool retention remains untreated for a prolonged period, the rectal wall becomes stretched, and the rectal vault enlarges. Some children with this problem experience significant anorectal pain, so they will repeatedly defecate small amounts of stool to achieve relief. These children are classically dirty while awake and tend to have very little soiling when sleeping.

Other children may have involuntary leakage of semiliquid stool around a hard stool mass. The child usually claims that he or she has not experienced the urge to defecate. This stage is often termed encopresis. Encopresis may also occur in the nonconstipated child who has severe psychogenic problems or in the child with a neuromuscular disorder.

EPIDEMIOLOGY

The normal frequency of bowel movements is age dependent. In the first 3 months of life, 95% of breast-fed infants have 5 to 40 bowel movements per week, while formula-fed infants have 5 to 25 bowel movements per week. In the second half of the first year, most babies will have 5 to 25 bowel movements per week, while toddlers from 1 to 3 years of age usually have 4 to 20 stools each week. The adult pattern of 3 to 14 bowel movements per week is established by about 4 years of age.

Constipation occurs in about 3% to 8% of children, with no ethnic, racial, or gender differences. It is estimated that 3% of children’s ambulatory health visits are for constipation. Fecal soiling occurs in 3% of 4-year-olds, 2% of 6-year-olds, and 1.5% of children between 7 and 11 years of age, with a male predominance of 3:1 to 6:1 (Everhart & Renault, 1991; Baker et al., 1999; Hyams, 1999; Nowicki & Bishop, 1999).

HISTORY AND PHYSICAL EXAMINATION

Causes of pediatric constipation are listed in Display 57-1. Historic points that must be obtained include the following:

Passage of meconium in the first 48 hours of life (if not, consider Hirschsprung’s disease)
Stool history in first year of life
History of toilet training (eg, trauma)
History suggestive of IBS
Average intake of dietary fiber (eating less than the minimum recommendation is a risk factor for chronic constipation in children; Morais, Vitolo, Aguirre, & Fagundes-Neto, 1999)
Family history

DISPLAY 57–1 • Causes of Pediatric Constipation

Functional

Irritable bowel syndrome

Dietary changes

Toilet training

Febrile illness

Fear

Withholding

Organic

Neuromuscular disorders: spinal defects, intestinal pseudo-obstruction, and so forth

Congenital defects: Hirschsprung’s disease, imperforate anus, anal stenosis, and so forth

Endocrine/metabolic: hypothyroid, hypercalcemia, hypokalemia, diabetes mellitus

Perianal: anal fissure, streptococcal cellulitis, atopic dermatitis

Gastrointestinal: gluten-sensitive enteropathy, cystic fibrosis, obstruction

Drugs/Toxins

Pelvic tumors

The provider should perform a complete physical examination, looking for evidence of hypothyroidism, neurofibromatosis, neuromuscular disorders, and anorectal abnormalities.

In particular, the abdominal examination should note muscle tone and abdominal contents. A diastasis recti can be noted by having the child do a sit-up. A diastasis recti will
dissipate the intra-abdominal pressure generated by a Valsalva’s maneuver, diminishing the ability to have effective bowel movements.

Gold, Levine, Weinstein, Kessler, and Pettei (1999) reported that pediatric providers often neglect to perform a digital rectal examination in the child with chronic constipation. The digital examination is important, because it can help the clinician to determine whether the patient’s constipation stems from a functional or an organic process. This differentiation is important because it may affect what therapy is prescribed.

The digital rectal examination should note rectal tone and rectal contents. A large rectal vault suggests chronic constipation or stool withholding. An anteriorly displaced anus with a posterior rectal shelf (noted on rectal examination) may make defecation difficult.

DIAGNOSTIC CRITERIA

Definitive criteria for diagnosis of constipation or encopresis have not been established. Diagnosis is almost always based on history and physical examination.

DIAGNOSTIC STUDIES

Occasionally, an abdominal radiograph may be needed to assess the amount of stool present in the patient who is difficult to examine or in the adolescent with a very muscular abdomen. If growth and development are abnormal in a child with constipation, then the pediatric provider should consider the following in the differential diagnosis:

Hypothyroidism
Gluten-sensitive enteropathy (celiac disease)
Cystic fibrosis

MANAGEMENT

The vast majority of children with constipation or encopresis can be managed solely by the primary care provider. Constipation in children often mandates the use of medication. In many adults with constipation, acceptance of dietary measures, including increasing fiber, is all that is necessary. Failure to treat a child’s constipation may result in an increase in problems, which in turn may lead to stool-withholding behavior and fecal soiling.

The addition of increased dietary fiber may also help the pediatric patient with functional constipation (Janicke & Finnev, 1999). In some instances, the provider also may find that referring the child and family for mental health evaluation and intervention can be efficacious. Janicke and Finney report that cognitive-behavioral treatment may prove useful when added to dietary interventions for functional constipation in children. Unfortunately, dietary manipulation is infrequently successful and may actually lead to caloric deprivation. The pediatric primary care provider is advised to seek nutritional counseling for the infant or younger child especially to ensure proper caloric provision.

Treatments for constipation can include the following:

Infants
- Barley malt extract 5 to 10 mL in formula twice daily
Children older than 1 year
- Dioctyl sodium sulfosuccinate 5 to 10 mL/kg once daily (softens stool)
- Senna 5 to 20 mL daily (laxative, effective in withholding)
- Bisacodyl (Dulcolax) one to two tablets once daily (or one suppository; irritant)

For clean-out or to manage intractable cases, polyethylene glycol lavage may prove efficacious, although the provider may need to use a nasogastric tube.

The provider should be certain of the following:

The constipated child does not have hypothyroidism or neurofibromatosis.
Hirschsprung’s disease was considered if there was no history of early passage of meconium or if the child passes ribbon- or snake-like stools.
In difficult to treat cases, physical examination for diastasis recti or an abnormally placed anus has occurred.

What to Tell Parents

Constipation may be a lifelong problem, but it usually becomes easier to treat with increasing age. Dietary manipulation is infrequently successful in children with constipation. Painful, hard stools are to be avoided to prevent withholding and encopresis. The school should make access to a bathroom easy so that children with constipation do not withhold stool.

Chronic and Recurrent Abdominal Pain

Chronic and recurrent abdominal pain are very common health care problems in pediatric practice. More than one third of children complain of abdominal pain that lasts 2 or more weeks (Lake, 1999). The term chronic abdominal pain is defined as discomfort that has lasted longer than 1 month. Recurrent abdominal pain requires three episodes of abdominal pain severe enough to limit activity and occurring for more than 3 months, with symptom-free intervals between the episodes of pain.

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