La dysphagie à endoscopie « normale »

La dysphagie est un motif fréquent de consultation en gastroentérologie. Elle est considérée, à juste titre, comme un symptôme d’alarme imposant le recours à l’endoscopie quelle que soit la présentation clinique. L’endoscopie va permettre le diagnostic de cancer de l’oesophage, d’oesophagite peptique sévère, de sténose peptique, d’achalasie de l’oesophage évoluée. Il est possible que l’endoscopie ne puisse pas identifier l’origine de la dysphagie pour plusieurs raisons : la cause n’est pas oesophagienne, les anomalies endoscopiques sont minimes ou non reconnues, ou il s’agit d’un trouble moteur oesophagien. La prise en charge diagnostique et thérapeutique des dysphagies d’origine oro-pharyngée ne sera pas détaillée dans ce texte

Direct detection of Helicobacter pylori resistance to macrolides by a polymerase chain reaction/DNA enzyme immunoassay in gastric biopsy specimens

BACKGROUND—The increasing use of macrolides especially in the treatment of Helicobacter pylori infection has led to an increase in resistant strains. The resistance of H pylori to macrolides, especially clarithromycin, is one of the major causes of eradication failure. In H pylori, clarithromycin resistance is due to point mutations localised in domain V of 23S rRNA. 
AIM—To develop a molecular technique based on amplification of a relevant fragment of the 23S rRNA and colorimetric hybridisation in liquid phase to detect directly in biopsy specimens the type of mutation associated with resistance of H pylori to clarithromycin. 
METHODS—Gastric biopsy samples from 61 patients were submitted to this test. The results were compared with standard methods (determination of minimal inhibition concentration, polymerase chain reaction/restriction fragment length polymorphism, and/or DNA sequencing) in order to evaluate the test and to define the cut off values, specificity, and sensitivity. 
RESULTS—The 14 biopsy samples in which H pylori was not detected did not give a positive result in any assay, and the 14 samples harbouring strains susceptible to clarithromycin gave a positive result with the wild type probe as expected. The 33 biopsy specimens containing resistant strains always gave a positive signal with one of the probes detecting resistant organisms, but in eight cases they also reacted with the wild type probe, indicating that a mixture of resistant and susceptible organisms was present. 
CONCLUSION—The importance of this new assay is that it allows the detection of multiple genotypes corresponding to either heterogeneous genotypes or mixed infections. Moreover, it allows in a single step not only the detection of H pylori but also the determination of its susceptibility to clarithromycin directly in biopsy specimens without the need for culture. 

 Keywords: Helicobacter pylori; resistance; clarithromycin; macrolide; polymerase chain reaction (PCR); immunoassa

Laser assisted ratio analyser 13C-ureu breath testing, for the detection of H. pylori: A prospective diagnostic European multicentre study

Background: Novel technology based on laser optogalvanic spectroscopy called the LARA (Laser Assisted Ratio Analyser) system was developed to measure 12C/13C ratios in breath samples using stable 13C isotopes, to detect Helicobacter pylori infection. Aim: To determine the sensitivity and specificity of the 13C-LARA-urea breath test in the detection of H. pylori infection in a prospective European multicentre trial; FDA-and EMEA-approved. Methods: Consecutive dyspeptic patients underwent diagnostic gastroscopy with biopsies for culture and histspathology, to detect H. pylori infection (gold standard). Subsequently, the LARA-urea breath test was performed using either a system without a cold trap (part I) or a system with a cold trap (part II). In both instances baseline, 30-min and 60-min breath samples were collected. The optimum cut-off level for 12C/13C ratios was determined by Receiver Operator Characteristics analysis. Results: In part I, 544 out of 604 patients were evaluable (low CO2: 47; withdrawn: 13). 284 out of 544 patients (52%) were H. pylori-positive according to the gold standard. The sensitivity of the LARA-urea breath test was 95% and the specificity 94%. In part II, 257 out of 272 were evaluable (low CO2: 14; withdrawn: 1). Sensitivity and specificity were 93% and 96%, respectively. Conclusion: The LARA-technology represents an accurate and non-invasive testing system for the detection of H. pylori infection. Its major advantages are the use of stable 13C isotope, the high throughput of samples and the easy means of collecting, storing and transporting the samples, thus making the system convenient to both patient and clinician