peptic ulcers simplified Flashcards
What are the investigations that you would perform with a presentation of epigastric pain, burning sensation that occurs after meals?
Carbon-urea breath test
Stool antigen test
What can the carbon urea and stool antigen test tell you?
If carbon is positive, likely to be H.pylori and this is confirmed by a positive stool test.
Summarise the pathophysiology of H.pylori
In the gastrum antrum, epithelia produces a mucous layer protective, H.pylori dissolves the mucous layer and causes epithelial cell death increasing exposure to acidity cause an ulcer.
What can you get as a result of severe ulceration?
Severe bleeding
What is the treatment for H.pylori peptic ulcer?
Amoxicillin and Clarithromycin(penicillin)/metronidazole - antibiotics
Protein pump inhibitor to reduce the secretion of stomach acid.
Triple therapy = 2 antibiotics and PPi
Is H.pylori gram negative or positive?
Negative
Give some basic information about Helicobacter Pylori
Gram negative
motile
microaerophilic bacterium (requires little free oxygen)
Resides in human GI exclusively colonising gastric type epithelium
Which type of bacterium to antibodies tend to be effective against?
Aerobic
How does helicobacter pylori lead to ulcer formation?
Increased gastric acid formation - increased gastrin or decreased somatostatin
Gastric metaplasia - cells transform due to excess acid
Downregulation of defence - reduced epidermal growth factor and reduced bicarbonate production
Summarise the virulence of helicobacter pylori
UREASE - catalyses urea into ammonium chloride and monochloramine which damages epithelial cells
Urease is antigenic and does evoke an immune response
Certain virulent strains produce CagA(antigenic) or VacA(cytotoxic) leads to more intense inflammation.
UREASE IS AN ENZYME PRODUCED BY H.PYLORI
What would be different in the case of chronic H.pylori positive peptic ulcer?
1st line therapy wasn’t effective so consider quinolone, tetracycline.
Proton pump inhibitor 4-12 weeks rather than 7 days, OMEPRAZOLE
Additive - bismuth sucralfate which is a chelating agent that reduces aciditiy of environment.
Physiological action of proton pumps?
H+/K+/ATPase pump expressed on secretory vesicles within parietal cells
Increased calcium leads to increase cAMP, translocation of secretory vesicle to apical parietal surface leading to H+ secretion.
How do proton pumps cause ulceration?
INCREASED ACTIVITY leading to increased H+ secretion reducing gastric pH
What percentage of peptic ulcers are H.pylori positive in developed world?
70%
What is the case when the carbon urea and stool antigen test come back negative with same presentation?
Usually a result of NSAID use
These patients tend to use NSAIDs