SUMMARY BackgroundBreath tests represent a valid and non-invasive diagnostic tool in many gastroenterological conditions. The rationale of hydrogen-breath tests is based on the concept that part of the gas produced by colonic bacterial fermentation diffuses into the blood and is excreted by breath, where it can be quantified easily. There are many differences in the methodology, and the tests are increasingly popular.

SUMMARY BackgroundRifaximin is a broad spectrum non-absorbable antibiotic used for treatment of small intestinal bacterial overgrowth. Doses of 1200 mg ⁄ day showed a decontamination rate of 60% with low side-effects incidence.

There is increasing evidence for a correlation between intestinal microbiota, bacterial translocation and hepatic steatosis. Intestinal microbiota affects nutrient absorption and energy homeostasis. Altered intestinal permeability may favor the passage of bacteriaderived compounds into systemic circulation, causing a systemic inflammatory state, characteristic of the metabolic syndrome. The interaction between intestinal permeability and luminal bacteria is involved in the pathogenesis and evolution of non-alcoholic liver disease. Microbiota pharmacological modulation could be a promising tool for a new therapeutical approach to non-alcoholic fatty liver disease.

Background/Aims: Acquired lactase deficiency is a common cause of gastrointestinal symptoms but its etiology remains unclear. Celiac disease could lead to lactase deficiency and is much more common than previously suspected. Several studies have highlighted the prevalence of lactose intolerance in celiac disease, but studies assessing the prevalence of celiac disease in lactose intolerance are lacking. We evaluated the prevalence of celiac disease in patients with a positive H₂-lactose breath test compared to a control group. Methods: This retrospective study included 54 patients (15 males/39 females; mean age 37.8 ± 7 years) from southern Italy, referred to the Gastroenterology Unit for bloating and diarrhea after the introduction of milk or dietary lactose. They had a positive H₂-lactose breath test and a negative H₂-glucose breath test. 50 blood donors were drawn from a similar population, matched for sex and age, and enrolled as a control group. All patients were screened for possible celiac disease by measuring the serum level of IgA antibodies to endomysium, anti-transglutaminase and total IgA. Patients positive for at least one of these markers were submitted to upper gastrointestinal endoscopy. Results: None of the patients had a IgA deficiency. 24% of the patients showed positivity of celiac disease antibodies compared to 2% in the control group (p < 0.001). Histologic samples of these patients showed villous atrophy (53.8% Marsh type IIIa, 38.4% Marsh IIIb, and 7.6% with Marsh type IIIc) confirming the celiac disease, while in the control subjects duodenal biopsies were normal. Conclusions: A high prevalence of celiac disease was observed in patients with a positive H₂-lactose breath test compared to healthy controls. In these subjects lactase deficiency seems to be the only manifestation of celiac disease. We suggest serologic screening for celiac disease in all patients with a positive H₂-lactose breath test before beginning a milk-exclusion diet.

The present study shows that a large proportion of CD patients experience a regression of lactose malabsorption after receiving a gluten-free diet. This may be related to normalization of the brush border with an improvement of lactase enzyme activity. LBT should be performed after 12 months in CD patients on a gluten-free diet in order to assess the persistence/disappearance of lactose malabsorption, thus avoiding an unnecessary lactose-free diet.