Stomach Flashcards
What type of drug can be used to prevent long term gastric damage caused by NSAIDs?
Give an example
How does it work?
A stable PGE1 analogue
E.g. Misoprostol
Inhibits basal and food-stimulated gastric acid formation
Also maintains secretion and mucus and bicarbonate
How does H.pylori cause gastric ulcers?
It secretes agents which cause persistent inflammation that weakens the mucosal barrier
This damages the mucosal cell layerand leaves the submucosa subject to attack by HCL
What are the three aims of drug treatment used to promote ulcer healing?
- Reducing acid secretion
- Increasing mucosal resistance
- Eradicating H.pylori
How do proton pump inhibitors work?
E.g. omeprazole
Inhibit the active (i.e. membrane inserted) H+/K+-dependent ATPase (proton-pump) to inhibit acid secretion
They are inactive at a neutral pH, but change conformation in a strongly acidic environment
Timing of dosing is important – drug must be present in plasma at an effective concentration whilst proton pumps are active.
How do histamine H2 receptor antagonists work?
E.g.
E.g. Ranitidine, cimetidine
Act as competitive (reversible) antagonists of H2 receptors
Completely block the histamine-mediated component of acid secretion and reduce secretion evoked by gastrin and Ach
Are effective against basal and stimulated gastric acid production
Are effective once/twice daily by oral administration
Unwanted effects (of ranitidine) are rare
Are used in the treatment of peptic ulcer and reflux oesophagitis
Give two examples of drugs used to strengthen the mucosa
Sucralfate
Bismuth chealate
Varices
What are they?
What are they caused by?
Complications?
Increased pressure in the portal vein causes the development of large, swollen veins (varices) within the esophagus and stomach. The varices are fragile and can rupture easily, resulting in a large amount of blood loss. The most common cause of portal hypertension is cirrhosis of the liver.
What are the most common cancers found in the stomach?
Adenocarcinoma - caused by H.pylori and other factors
Lymphoma
GISTs - gastrointestinal stroma tumours
In terms of surgery, how is a proximal vs distal tumour treated?
Total gastrectomy for proximal lesions
Patial gastrectomy for distal lesions
According to the Rome III criteria, what are the three main groups of dyspepsia?
- Epigastric pain or burning (epigastric pain syndrome)
- Postprandial fullness (postprandial distress syndrome)
- Early satiety (postprandial distress syndrome)
What are some common risk factors for gastric and duodenal ulcer formation?
H.pylori; drugs - e,g NSAIDs, steroids; increased gastric acid secretion; smoking, slow gastric emptying
What is the main difference in symptoms between gastric ulcers and duodenal ulcers?
Duodenal ulcers cause pain before meals (or at night), and pain is relieved by eating or drinking milk
Gastric ulcers cause pain on eating, and are relieved by antacids
What is functional dyspepsia?
Presence of one of the following: - Bothersome postprandial fullness - Early satiation - Epigastric pain - Epigastric burning And no evidence of anystructural disease
What is the most accurate non-invase test for H.pylori?
C13 breath test
What is the current treatment for H.pylori?
Either:
- Full dose PPI + amoxicillin + clarithromycin
- Full dose PPI + metronidiazole + clarithromycin