Sorbitol H2-breath test versus anti-endomysium antibodies to assess histological recovery after gluten-free diet in coeliac disease

Hydrogen Breath Tests: Are They Really Useful in the Nutritional Management of Digestive Disease?

Background: Carbohydrate malabsorption is a frequent digestive problem associated with abdominal pain, bloating and diarrhea. Hydrogen breath testing (BT) represents the most reliable and validated diagnostic technique. The aim of this manuscript was to clarify the usefulness of BTs in the nutritional management of these disorders. Methods: A literature search for BT related to carbohydrate malabsorption was carried out using the online databases of Pubmed, Medline and Cochrane. Results: Lactose BT showed good sensitivity and optimal specificity for lactose malabsorption. However, an accurate diagnosis of lactose intolerance should require blind lactose challenge although this method is difficult to utilize in clinical practice. Regarding dose-depending fructose and sorbitol malabsorption, BTs could not add diagnostic advantage compared with a direct dietary intervention. In addition, carbohydrates are fundamental components of fermentable oligo-, di- and monosaccharides and polyols (FODMAPs). Before starting a low FODMAP diet, lactose BT should be suggested in a population with low prevalence of hypolactasia. Conclusions: BTs represent a valid and noninvasive technique in many digestive conditions. Regarding the management of carbohydrate intolerance, lactose BT can be recommended with some limitations. No sufficient evidence is available about the usefulness of BTs for other sugars in clinical practice.

Overview of biomarkers for diagnosis and monitoring of celiac disease

Among the adverse reactions caused by wheat, celiac disease (CD) is the longest studied and best-known pathology. The more recently defined non-celiac gluten sensitivity (NCGS) presents with symptoms which are often indistinguishable from CD. Diagnosis of CD is based on serologic, molecular, and bioptic testing. The IgA anti-transglutaminase (tTG) test is considered highly important, as it shows high sensitivity and specificity and its levels correlate to the degree of intestinal damage. Small bowel biopsy can be avoided in symptomatic patients with IgA anti-tTG levels above 10× the manufacturer's cut-off. Recently, tests of anti-deamidated peptides of gliadin (DGP) have replaced classic anti-native gliadin (AGA) tests. DGP assays have a considerably higher diagnostic accuracy than AGA assays, especially in the IgG class, and can replace anti-tTG tests in patients with selective IgA deficiency. The combination of IgG anti-DGP plus IgA anti-tTG assays show greater sensitivity than a single test, with very high specificity. EMA tests have great diagnostic accuracy but are not recommended by all the latest guidelines because they are observer dependent. Biopsy must still be considered the gold standard for CD diagnosis. HLA-DQ genotyping can be used to screen asymptomatic children and in cases of histology/serology disagreement. About half of NCGS patients are DQ2 positive and have IgG AGA. To diagnose NCGS, first CD and wheat allergy must be excluded; then the wheat dependence of symptoms must be verified by a gluten-free diet and subsequent gluten challenge.

Follow-up of coeliac disease with the novel one-hour 13C-sorbitol breath test versus the H2-sorbitol breath test

BACKGROUND

We recently developed a (13)C-sorbitol breath test ((13)C-SBT) as an alternative to the H(2)-sorbitol breath test (H(2)-SBT) for coeliac disease. In this study we compared the diagnostic properties of the H(2)-SBT and the (13)C-SBT in follow-up of coeliac disease.

MATERIAL AND METHODS

Twenty-seven coeliac patients on a gluten-free diet (GFD) performed the breath tests. All had been tested before treatment in the initial study of the (13)C-SBT, in which 39 untreated coeliac patients, 40 patient controls, and 26 healthy volunteers participated. Five gram sorbitol and 100 mg (13)C-sorbitol were dissolved in 250 ml tap water and given orally. H(2), CH(4) and (13)CO(2) were measured in end-expiratory breath samples every 30 min for 4 h. Increased H(2) concentration ≥20 ppm from basal values was used as cut-off for the H(2)-SBT. Sixty minutes values were used as diagnostic index in the (13)C-SBT.

RESULTS

(13)CO(2) levels at 60 min increased in 20/26 treated coeliac patients (77%) after GFD, but were significantly lower than in control groups. Out of 20 patients who had a positive H(2)-SBT before GFD, 12 had a negative H(2)-SBT after GFD. Peak H(2) concentrations were not correlated with (13)C-SBT results.

CONCLUSION

The study confirms the sensitivity of a one-hour (13)C-SBT for small intestinal malabsorption. The (13)C-SBT has superior diagnostic properties compared with the H(2)-SBT in follow-up of coeliac disease.

Pediatric gastric and duodenal disorders

PURPOSE OF REVIEW

This review provides a summary of new developments regarding common diseases affecting the stomach and duodenum in children.

RECENT FINDINGS

Celiac disease seems to be more prevalent than previously thought in different areas of the world, including the United States. The value of different serologic screening tools and other noninvasive tests has been carefully assessed. HLA-DQ typing has been proposed as part of celiac disease screening testing for high-risk groups. The use of the newly defined pediatric Rome criteria is allowing recognition of nonulcer (or functional) dyspepsia as an entity that affects a sizable subset of children. Testing of gastric sensory and motor function is clarifying the pathophysiology of this condition in children and adolescents. Intriguing data are also emerging about the possible role of mucosal eosinophils and disaccharidase deficiencies in causing dyspeptic symptoms. Intrasphincteric injection of botulinum toxin A represents a novel technique to treat gastroparesis. In refractory cases, the use of a gastric electric stimulator has shown to be beneficial in idiopathic and diabetic gastroparesis. Progress has been made in understanding the epidemiology of Helicobacter pylori infection in developing countries and its role in causing a wide spectrum of symptoms in children. Several noninvasive methods for its diagnosis have been established.

SUMMARY

Recent developments in the diagnosis and management of gastric and duodenal pathologic conditions are making a significant impact on pediatric clinical care. Future studies will likely continue to explore the use of minimally invasive testing and interventions in such conditions.

Advances in celiac disease

PURPOSE OF REVIEW

The number of diagnoses of celiac disease, especially "silent" forms continues to rise world-wide. This review aims to summarize critically recent research in celiac disease.

RECENT FINDINGS

New proteomic approaches with the development of a possible powerful animal model have potentially furthered the isolation of the epitopes within gliadin, and other related proteins, that are critical for the development of celiac disease.

SUMMARY

The number of potential disease-triggering gliadin components remains large. Small bowel biopsies remain the gold-standard for both diagnosis and monitoring of treatment.

Lack of usefulness of anti-transglutaminase antibodies in assessing histologic recovery after gluten-free diet in celiac disease

Gluten-free diet (GFD) plays a key role in the treatment of celiac disease (CD), but it is difficult to evaluate the effect of GFD on the improvement of villous architecture using sensitive, non-invasive tests. Aim of this study is to evaluate anti-transglutaminase (tTG) antibodies in the follow-up of CD to detect histologic recovery. We studied 42 consecutive patients with CD. In all the patients anti-tTG antibodies (evaluated by the enzyme linked immunosorbent assay method) and EGDscopy with multiple bioptic samples before GFD and then 6, 12, and 18 months after GFD were evaluated. For comparison, a sorbitol H2-breath test (H2-BT) and anti-endomysium (EMA) antibodies test were carried out concomitantly. Anti-tTG results were positive in 36 of 42 patients before GFD (80.95%), while they were positive in 11 of 34 (32.35%), 1 of 17 (5.88%), and 0 of 6 (0%) of patients with a persistence in histologic lesions 6, 12, and 18 months of GFD respectively, without any correlation with persistence of histologic lesions (P = NS). Also EMA failed to show correlation with improvement of histologic lesions. They were positive in 31 of 42 patients before GFD (73.80%), while they were positive in 18 of 34 (52.94%), 3 of 17 (17.64%), and 0 of 6 (0%) cases 6, 12, and 18 months of GFD respectively (P = NS). Regarding sorbitol H2-BT, it was positive in 40 of 42 (95.24%) patients before GFD, while it was positive in 31 of 34 (91.17%), 13 of 17 (76.47%), and 4 of 6 (50%) of patients with a persistence in histologic lesions 6, 12, and then 18 months after GFD starting (see Fig. 2, infra). So, anti-tTG and EMA were ineffective in assessing the histologic recovery at each follow-up visit (P = NS), while sorbitol H2-BT seems more effective than anti-tTG and EMA in this field (P < 0.0001 sorbitol H2-BT versus anti-tTG and versus EMA at 18 months after gluten withdrawal). Thirty-eight of 42 (90.47%) patients adhered to a strict GFD. Four patients were found to have occasional dietary transgression, and in all we noted a progressive decreasing of anti-tTG after 6 months of GFD and negative anti-tTG after 12 months of GFD, but sorbitol H2-BT persisted being positive during the entire follow-up. Intestinal damage persisted during the follow-up, despite anti-tTG and EMA negativity, and worsened in the presence of dietary lapses. Anti-tTG does not seem effective to assess histologic recovery in the follow-up of celiac patients after they have started GFD due to its poor correlation with histologic damage.