Management of Functional Abdominal Pain and Irritable Bowel Syndrome in Children and Adolescents

Eric Chiou; Samuel Nurko

Disclosures

Expert Rev Gastroenterol Hepatol. 2010;4(3):293-304. 

In This Article

Dietary Therapy

Restrictive Diets

Lactose intolerance has long been implicated as a possible factor in IBS, especially for patients with predominant symptoms of diarrhea. Brush border lactase activity peaks at around 3 years of age then gradually decreases with age. A diagnosis of lactase deficiency is unlikely in younger children, but can be considered for older children and adolescents, although data to support empiric recommendation of a lactose-free diet are weak. Dearlove et al. studied 21 children with RAP in a double-blind, crossover trial.[14] Patients were given a lactose-free diet for 2 weeks, then for the next 2 weeks they were given either lactose or placebo. At the end of the study, there were no differences in pain symptoms or the number of children reporting relief between the lactose or placebo group. Lebenthal et al. performed lactose tolerance testing (2 g/kg) on 69 children (aged 6–14 years) with RAP.[15] Of this group, 21 children were found to have abnormal results, documented by a blunted rise in blood glucose. These patients then underwent three successive 6-week, double-blinded diet trials of cow's milk formula containing lactose, soy-based and lactose-free formula, and normal diet and milk consumption. Pain frequency was increased in ten out of 21 patients after being given the cow's milk formula compared with their regular diet. However, pain was also increased in seven out of 21 patients after being given the lactose-free soy formula. In addition, a 12-month trial of a lactose-free diet did not result in any difference in abdominal pain for patients determined to be lactose tolerant versus intolerant.

Malabsorption of other carbohydrates, such as fructose, has also been implicated in the pathogenesis of chronic abdominal pain. Persistence of fructose in the GI tract, especially in the form of high-fructose corn syrup, is postulated to cause an osmotic diarrhea, as well as serve as a substrate for fermentation by colonic bacteria, resulting in the production of gas. Gomara et al. administered fructose breath tests with random amounts of fructose (1, 15 or 45 g) to children presenting with persistent unexplained abdominal pain.[16] Higher doses of fructose administered in the tolerance test were associated with increased GI symptoms, such as nausea, bloating and abdominal pain. Out of 32 children studied, 11 were found to have abnormal test results in the form of elevated breath hydrogen levels above baseline. When these 11 children underwent dietary restriction of fructose, nine children reported a rapid improvement of their gastrointestinal complaints. After 2 months, all nine children continued to report improvement, especially for symptoms of abdominal pain and bloating (p < 0.05).

Dietary Fiber

Many physicians routinely recommend the use of bulking agents or dietary fiber to produce more regular bowel movements and to decrease abdominal pain associated with FAP or IBS. These agents are thought to help by softening stool and enhancing colonic transit. In adults, evidence to support the use of fiber is limited by conflicting results and poor-quality studies. In a meta-analysis, the benefit of dietary fiber for adults with IBS was limited to psyllium hydrophilic mucilloid (ispaghula husk); wheat bran and corn bran were no better than placebo.[17]

In children, the data on dietary fiber are even sparser. The role of fiber in RAP is somewhat supported by a case-controlled study comparing children with RAP with normal controls, which found that 78% of subjects in the RAP group had low intake of fiber below the recommended level, compared with 51% of the control group (p = 0.021).[18] For treatment of RAP, Feldman et al. randomized 52 children with a history of having at least one attack of unexplained abdominal pain per week over at least 2 months and having pain severe enough to affect activity, to receive either a 5 g corn fiber cookie or placebo cookie twice daily for 6 weeks.[19] In total, 13 out of 26 (50%) patients in the fiber group reported at least a 50% decrease in the frequency of pain episodes compared with 27% in the placebo group (p < 0.05). However, a recent Cochrane review questioned whether the appropriate statistical analysis was performed in the original study and reanalysis of the same data found no difference between the two treatment groups.[20]

Christensen et al. performed a randomized double-blinded placebo-controlled study of 40 children with a diagnosis of RAP, which was defined as having at least two pain episodes in the preceding 6 weeks that were severe enough to affect activity.[21] Patients received either ispaghula husks (66% fiber) or placebo (2% fiber) in the form of cereal twice daily for 7 weeks. During the last 6 weeks of the study, there was no significant difference in the mean number of pain episodes in the fiber group compared with the placebo group (13.5 vs 13 episodes, respectively). The benefit of dietary fiber in the treatment of RAP and IBS in children is unclear and should be weighed against the low but potential risk of increased pain and bloating, which has been reported in some adult studies of IBS patients given bran fiber.[22] On the other hand, an empiric trial of psyllium husk fiber may be reasonable, especially if there are associated symptoms of constipation.

Probiotics

Commensal bacteria of the GI tract are believed to play an important role in homeostasis, while alterations to these populations have been implicated in dysmotility, visceral hypersensitivity, abnormal colonic fermentation and immunologic activation.[23,24] This hypothesis has been further supported by reports of IBS triggered by gastrointestinal infections and antibiotic use, both of which can disrupt normal enteric bacteria, as well as the finding of significantly decreased populations of normal Lactobacillus and bifidobacteria in patients with diarrhea-predominant IBS.[25] Probiotics commonly contain Lactobacillus, bifidobacteria or other living microorganisms thought to be healthy for the host organism when ingested in sufficiently large amounts. Probiotics may improve IBS symptoms by restoring the microbial balance in the gut through metabolic competition with pathogens, by enhancing the intestine's mucosal barrier or by altering the intestinal inflammatory response.[26] Different methods, formulations, dosages and outcome measures have made it difficult to make conclusions about the efficacy of probiotics. A recent meta-analysis concluded that probiotics as a class appeared to be efficacious for adults with IBS, although the magnitude of benefit and most effective species, strain and dosing are not clear.[27]

Data in pediatric studies have been equally conflicting. In a double-blind placebo-controlled trial, Bausserman et al. randomized 64 children with IBS according to Rome II criteria to receive either Lactobacillus GG (1 × 1010 colony forming units) or placebo twice daily for 6 weeks.[28] Patients had similar rates of abdominal pain relief regardless of treatment: 44% in the Lactobacillus GG group compared with 40% in the placebo group. There was no significant difference in other gastrointestinal symptoms, except for decreased perception of abdominal distension for patients receiving Lactobacillus.

Gawronska et al. studied children with either FAP, IBS or functional dyspepsia, all diagnosed according to Rome II criteria.[29] Patients were stratified by diagnosis and then randomized to Lactobacillus GG (3 × 109 colony forming units) capsules versus placebo twice daily for 4 weeks. In the subset of 37 patients with IBS, 33% of those treated with Lactobacillus reported no pain at the end of treatment compared with 5% in the placebo group (p = 0.04). IBS patients also reported a significantly decreased frequency of pain episodes with Lactobacillus (p = 0.02). However, for patients with FAP or functional dyspepsia, Lactobacillus did not provide any significant benefit over placebo.

Finally, in a study conducted by Bu and colleagues, 45 children under the age of 10 years with chronic constipation and abdominal pain were randomized to receive either Lactobacillus casei rhamnosus, magnesium oxide or placebo twice daily for 4 weeks.[30] Patients receiving either Lactobacillus or magnesium oxide had increased bowel movement frequency (p = 0.03) and improved stool consistency (p = 0.01) compared with placebo. Frequency of abdominal pain was significantly decreased in the probiotic group compared with both magnesium oxide and placebo (p = 0.03).

Overall, there is no conclusive evidence that dietary carbohydrate restriction, fiber supplementation or probiotic supplementation are effective in the management of FAP and IBS. Further studies are needed to evaluate the role of dietary interventions; until then, these options may be considered on a case-by-case basis after careful discussion with the patient and family.

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