Helicobacter pylori Flashcards
What is H.pylori?
A gram negative aerobic bacteria that lives in the stomach
What does H.pylori do?
Damages the epithelial lining of the stomach and causes gastritis, ulcers and predisposes to stomach cancer
How does H. pylori cause damage?
Avoids acidic environment by forcing its way into the gastric mucosa, exposing the epithelial cells to acid and produces ammonia which neutralises the stomach acid and damages the epithelial lining
What are the tests for H. pylori?
Urea test - using radiolabelled Carbon13
Stool antigen test
Rapid urease test aka CLO test
What do patients need to do before any H.pylori tests?
Be off their PPI/ H2RA for 2 weeks
What is a rapid urease/ CLO test
Campylobacter-like organism test
performed during endoscopy - take small biopsy of gastric mucosa
urea added to the sample - if H.pylori are present. they produce urease enzymes to turn urea into ammonia
Ammonia makes the sample alkali - giving a positive result when pH is tested
H. pylori eradication
Involves triple therapy with a PPI and two antibiotics for 7 days
What is the PAC 500 eradication regime?
PPI: lansoprazole 30mg BD
Amoxicillin 1g BD
Clarithromycin 500mg BD
What is the PMC 250 eradication regime?
PPI: lansoprazole 30mg BD
Metronidazole 400mg BD
Clarithromycin 250mg BD
What is the success rate of H.pylori eradication therapy?
95% success rate
if not, mostly due to poor compliance
Add bismuth –> stools become tarry black
Which test can be used to test if eradication was successful?
Urea breath test - but not routinely necessary
