Helicobacter Pylori Class 2024 PDF

Helicobacter Pylori Dr Alfredo Jover Updated september 2023 Infecciones Emergentes  Helicobacter Pylori What is it? – A spiral-shaped gram-negative bacterium Found in colonized gastric mucosa or adherent to the epithelial lining of the stomach Causes continuous gastr...

Helicobacter Pylori Dr Alfredo Jover Updated september 2023 Infecciones Emergentes  Helicobacter Pylori What is it? – A spiral-shaped gram-negative bacterium Found in colonized gastric mucosa or adherent to the epithelial lining of the stomach Causes continuous gastric inflammation in virtually all infected persons Urease hydrolyzes urea into CO2 and ammonia and allows H. pylori to survive in acidic environment  How do you get infection? Infection is acquired via ingestion orally Transmitted during childhood in most cases Prevalence varies geographically Risk factors—increased age, AA or LA, lower level of education, developing country May be asymptomatic (90% of infected) May have sx of dyspepsia –burning, distention/ bloating, nausea, belching/ flatulence, halitosis  Prevalence What percent of Spanish population is infected with H. pylori? Estimated 30-40% (70% age >50, 20% 10 yrs. H. pylori increases risk of MALT lymphoma What tests are available? Non-invasive Diagnostic Tests – Serologic tests – Urea breath tests – Stool antigen Endoscopic Tests – Urease – Histology – Culture – PCR  Gold Standard? According to 2023 CEC Guidelines “there is no single test that can be considered the gold standard for the diagnosis of H. pylori” Most appropriate test depends on clinical situation  Serologic Tests ELISA to detect IgG or IgA antibodies IgG Ab appear 2-3 weeks following infxn and slowly decrease after eradication Inexpensive and widely available Sensitivity and specificity – Sensitivity 85% and specificity ~80% (from meta- analysis) – Lower than in previous reports If pretest probability is low, a negative test excludes dz. If test is positive it may be a false + so recheck with a confirmatory test  Serologic Tests False + are more common in elderly and pt w/ cirrhosis Also, may underestimate infxn in elderly b/c lack of Ab response (false -) Not reliable in young children Poor PPV in low prevalence populations Limited use for F/U of therapy – Takes a long time for serology to become negative – In pt cured of infection, titers are at ~50% at 3 mths  CEC Guideline For populations with a low pretest probability of H pylori infection, the nonendoscopic urea breath and fecal antigen tests have a better positive predictive value than do antibody tests. Antibody testing identifies an immunologic reaction to the infection, whereas the urease tests and fecal antigen test identify the presence of active H pylori infection. A 40 yo male has severe GERD for which he takes a PPI. He has developed dyspepsia and abdominal pain that is new. He has tried to stop his PPI, but severe symptoms recur within days. You are inclined to employ the test and treat strategy for H. pylori. Which study do you order? A. H. pylori IgG serology B. Fecal antigen test C. Urea breath test D. EGD  Answer Serology would be appropriate in this scenario for patients on PPI therapy who cannot stop therapy for two weeks prior to the tests of active infection, i.e. stool antigen or breath test.  Urea Breath Test Hydrolysis of urea ! CO2 and NH3. Measures labeled carbon. Sensitivity and specificity typically >95% in most studies False negatives with PPI, Abx, bismuth – Off Abx and bismuth for >4 weeks – Off PPI for > 2 weeks Used for both initial dx and F/U – Wait 4 weeks before repeat for follow-up  Stool Antigen Test Sensitivity and specificity ~90% False positive (decreased specificity) in pt with acute UGI bleed False negative tests (decreased sensitivity) if patient is on PPI in prior 2 weeks or has taken antibiotics in prior 4 weeks. (24 hours for H2 blocker) Useful for documenting if eradication has been successful Wait 4-8 weeks before repeat  Endoscopy When to choose endoscopy – Alarm sx such as anemia, GI bleeding, weight loss – >50 yrs age 4 methods of testing: biopsy urease test, histology, bacterial culture, PCR According to AAFP article (2002) Steiner’s stain for microscopic exam is gold standard According to ACG (1998), first choice is urease test on an antral biopsy  Biopsy Urease Test Sensitivity >90% and Specificity >95% Biopsy urease testing is less expensive than histology If biopsy urease test is negative, consider histology or serology Biopsy urease tests have decreased sensitivity in pt on PPI and in pt with recent or active bleeding False negatives: recent bleed, PPI, H2 blocker, Abx, bismuth Stop PPI and other meds that may interfere 4 wks prior to endoscopy  Culture and PCR Primary means by which Abx sensitivities can be determined Neither is widely available for clinical use Not routinely recommended  Ar tic le s The low clarithromycin resistance rate coupled with the high rates of metronidazole resistance may support the recovery of the classical triple therapy in our healthcare area. Antibiotics 2023, 12, 356. https://doi.org/ 10.3390/antibiotics12020356 Which of these patients should be tested for H. pylori, rather than have endoscopy? A. 63 yo female with anemia and early satiety. B. 46 yo male with progressive dysphagia and history of weight loss C. 56 yo with new onset dyspepsia and recurrent vomiting for the past 2-3 months D. 40 yo female with abdominal pain and dyspepsia  Test and Treat Strategy Uninvestigated dyspepsia (ie, unknown if pt has PUD)