Peptic Ulcers Flashcards
What is an ulcer?
It is a breach in a mucosal surface
What are the 4 causes of peptic ulcers?
Helicobacter pylori infection
Drugs-NSAIDS
Chemical irritants - alcohol, bile salts , dietary factors
Gastrinoma
What are the 4 protective mechanisms of gastric mucosa?
Alkaline mucus on luminal surface
Tight junctions between epithelial cells
Replacement of damaged cells-stem cells at the base of pits to produce new cells
Feedback loops
Where is the helicobacter pylori infection found / living?
Bacteria live in gastric acid
What do the helicobacter pylori do?
Most common infection
Secretes urease, splitting urea into CO2 + ammonia
Ammonia + H+ = Ammonium
Ammonium is toxic to gastric mucosa, less mucus produced
Secreted proteases, phospholipases & vacuolating cytotoxin A - attack gastric epithelium
What are the results of a helicobacter pylori infection?
Results in inflammatory response & less mucosal defense
What are the treatments for the helicobacter pylori infection?
Triple therapy
1 proton pump inhibitor
2 antibiotics
What does the proton pump inhibitor do and how does it help the treatment of the helicobacter pylori infection?
Inhibits pumping of H+ ions into the stomach, increasing gastric pH making conditions inhospitable for bacteria
What antibiotics are used to treat helicobacter pylori infection?
Clarithromycin
Amoxicillin
Tetracycline
Metronidazole
What are NSAIDs?
Non steroidal anti inflammatory drugs
Aspirin, ibuprofen
How do NSAIDs cause peptic ulcers?
Mucous secretion is stimulated by prostaglandins
Cyclo-oxygenase 1 is needed for prostaglandin synthesis
NSAIDS inhibit cyclo-oxygenase 1
Reduced mucosal defense
What is the treatment for NSAIDs caused peptic ulcers?
Prostaglandin analogues (mimic effect of prostaglandins) eg. Misoprostol Reduce acid secretion
Examples of chemical irritants causing peptic ulcers and what they do?
Alcohol, bile salts
Duodenal gastric reflux causes bile to enter stomach, alkaline bile strips away gastric mucous layer
Reduced mucosal defense
How does gatrinoma cause peptic ulcers?
Rare tumours of parietal cells, excessive gastrin release, increase gastric acid, increased attack on gastric mucosa, ulcer
Apart from proton pump inhibitors, what is another way to reduce gastric acid secretion, what drug?
H2 receptor agonist
Block receptors for histamine thereby reducing acid secretion
Eg. Cimetidine, ranitidine
