Diagnóstico de proliferación bacteriana intestinal en niños: evidencia experimental para sustentar el empleo de lactulosa en la prueba de hidrógeno y su validación como prueba tamiz

Is small-bowel bacterial overgrowth an underdiagnosed disorder in children with gastrointestinal symptoms?

Small-bowel bacterial overgrowth (SBBO) has been implicated in chronic abdominal pain and irritable bowel syndrome in children. This was a retrospective study that aimed to assess the occurrence of SBBO by the lactulose breath hydrogen test in children referred primarily for investigation of carbohydrate malabsorption (n = 287). There were profiles indicative of SBBO in 16% (39/250) of hydrogen-producing children. This indicated that SBBO may be more common in children with gastrointestinal symptoms and apparent carbohydrate malabsorption than previously recognised.

Double-blind, placebo-controlled antibiotic treatment study of small intestinal bacterial overgrowth in children with chronic abdominal pain

BACKGROUND AND OBJECTIVES

Chronic abdominal pain (CAP) in children may be a precursor to irritable bowel syndrome (IBS) in adults. The prevalence of abnormal lactulose breath tests (LBT) suggesting small intestinal bacterial overgrowth (SIBO) has been reported as 91% in children with CAP and 35% in healthy controls. In addition, patients with IBS with SIBO who responded to nonabsorbable antibiotic treatment with normalization of LBT reported 75% global improvement in symptoms. The aim of the study was to test whether treatment with a nonabsorbable antibiotic may reduce symptoms in children with CAP.

METHODS

Seventy-five children ages 8 to 18 years with CAP based on Rome II criteria were enrolled. Subjects underwent baseline LBT and completed symptom-based questionnaires. They were then randomized in a 2:1, double-blind fashion to receive a 10-day course of 550 mg of rifaximin or placebo 3 times per day (t.i.d.). LBT and questionnaires were repeated 2 weeks after treatment.

RESULTS

Forty-nine children received rifaximin and 26 received placebo. There were no differences in demographics between groups. Ninety-four percent who received rifaximin and 92% who received placebo had abnormal baseline LBT, suggesting SIBO (not significant [NS]). There was no significant difference in symptom improvement between groups; however, only 20% of children treated with rifaximin achieved a normalized repeat LBT, demonstrating successful treatment of SIBO.

CONCLUSIONS

Similar to adults with IBS, the prevalence of abnormal LBT suggesting SIBO in children with CAP is high; however, treatment with 10 days of rifaximin has low efficacy in normalizing LBT in this group. Additional studies are needed to determine whether a treatment approach with higher efficacy would lead to improvement in children with CAP.

Small intestinal bacterial overgrowth

Despite the current increase in interest in the role of the microbiota in health and disease and the recognition, for over 50 years, that an excess of colonic-type flora in the small intestine could lead to a malabsorption syndrome, small intestinal overgrowth remains poorly defined. This lack of clarity owes much to the difficulties that arise in attempting to arrive at consensus with regard to the diagnosis of this condition: there is currently no gold standard and the commonly available methodologies (the culture of jejunal aspirates and a variety of breath tests) suffer from considerable variations in their performance and interpretation, leading to variations in the prevalence of overgrowth in a variety of clinical contexts. Treatment is similarly supported by a scant evidence base and the most commonly used antibiotic regimens owe more to custom than clinical trials.

[Usefulness of lactulose breath test for the prediction of small intestinal bacterial overgrowth in irritable bowel syndrome]

BACKGROUND/AIMS

Lactulose breath test (LBT) has been used as a presumptive surrogate marker for small intestinal bacterial overgrowth (SIBO). However, recent reports suggest that abnormal LBT cannot discriminate patients with irritable bowel syndrome (IBS) from the control. Thus, the aim of this study was to evaluate the usefulness of LBT in IBS.

METHODS

LBT from 76 IBS patients, 70 functional bowel disorders (FBD), and 40 controls were examined. LBT was considered positive if (1) baseline breath hydrogen (H₂) >20 parts per million (ppm) or rise of breath H₂ >20 ppm above the baseline in <90 mins, or (2) baseline breath methane (CH₄) >10 ppm or rise of breath CH₄ >10 ppm above the baseline in <90 mins. The subjects were categorized into predominant hydrogen producers (PHP), predominant methane producers (PMP), combined producer, and both negative group based on LBT.

RESULTS

The rate of abnormal LBT in the IBS, FBD, and control group were 44.7%, 41.4%, and 40.0% respectively without significant differences. The rate of PHP or PMP was not significantly different among the IBS, FBD, and control group. When clinical characteristics were analyzed in IBS and FBD according to LBT types, IBS subtypes and symptoms were not significantly different.

CONCLUSIONS

LBT was not useful to discriminate IBS/FBD patients from the control. The assessment of SIBO by LBT in IBS should be revalidated in the future.

Chronic abdominal pain in children is associated with high prevalence of abnormal microbial fermentation

BACKGROUND

Chronic abdominal pain (CAP) in children, a condition that accounts for approximately 25% of pediatric gastroenterology office visits, may be a precursor to irritable bowel syndrome in adults. Recently, small intestinal bacterial overgrowth (SIBO) has been reported in 78-84% of IBS patients regardless of their abdominal symptoms, compared to 20% in healthy controls. Aims The aim of this study was, therefore, to assess the prevalence of SIBO in children with CAP.

METHODS

Seventy-five children aged 8-18 years diagnosed with CAP based on the Rome II criteria and 40 healthy controls were enrolled. All subjects underwent a lactulose breath hydrogen test (LBT) to assess for SIBO. Children with CAP also filled out symptom questionnaires.

RESULTS

There was a 91% prevalence of an abnormal LBT suggestive of SIBO in the children with CAP and 35% in controls (odds ratio = 16.7, 95% confidence interval 6.0-57.5, P < 0.0001). A comparison of CAP children with a positive LBT to CAP children with a negative LBT revealed the former had significantly more "urgency to have a bowel movement" (P = 0.049) and experienced less "soiling" (P = 0.016) than those with a negative LBT. No significant differences were found between the two groups in terms of the location of their pain or any other associated symptoms.

CONCLUSIONS

Similar to adults with IBS, there is a significantly higher prevalence of SIBO in children with CAP. Randomized controlled studies are needed to determine if eradication of SIBO will lead to symptom improvement in these patients.

Prevalence of small intestinal bacterial overgrowth in children with irritable bowel syndrome: a case-control study

OBJECTIVE

To assess the prevalence of small intestinal bacterial overgrowth (SIBO) in children affected by irritable bowel syndrome (IBS).

STUDY DESIGN

Consecutive children affected by IBS according to Rome II criteria (n = 43) were enrolled at the Gemelli Hospital, Catholic University of Rome. The control population (n = 56) consisted of healthy subjects without IBS symptoms, similar to patients for age, sex, and social background. All subjects underwent lactulose/methane breath test (LBT) to assess small intestinal bacterial overgrowth.

RESULTS

The prevalence of abnormal LBT result was significantly higher in patients with IBS (65%, 28/43) with respect to control subjects (7%, 4/56; OR 3.9, 95% CI 7.3-80.1, P < .00001). Patients with abnormal LBT showed a trend toward a worse visual analog scale score with respect to children with IBS without SIBO, but a significant statistical difference was observed only for bloating.

CONCLUSIONS

Results from this study suggest a significant epidemiologic association between SIBO and IBS in childhood. Placebo-controlled interventional studies with antibiotics used to treat bacterial overgrowth are warranted to clarify the real impact of the disease on IBS symptoms.

Diagnosis of small intestinal bacterial overgrowth: the challenges persist!

Small intestinal bacterial overgrowth was originally defined in the context of an overt malabsorption syndrome and diagnostic tests were developed and validated accordingly. More recently, the concept of intestinal contamination with excessive numbers of bacteria, especially those of colonic type, has been extended beyond the bounds of frank maldigestion and malabsorption to explain symptomatology in disorders as diverse as irritable bowel syndrome, celiac sprue and nonalcoholic fatty liver disease. Owing to a lack of consensus with regard to the optimal diagnostic criteria (the 'gold standard') for the diagnosis of bacterial overgrowth, the status of these new concepts is unclear. This review sets out to critically appraise the various diagnostic approaches that have been taken and are currently employed to diagnose small intestinal bacterial overgrowth.