Stomach and duodenum

Question 1

Name 4 ways of determining a subject’s H. Pylori status?

Answer 1

1) Breath test. 2)Gastric biopsy. 3) Serum test. 4)Stool antigen

Question 2

What are the 2 main causes of peptic ulcers?

Answer 2

NSAIDs and Helicobacter Pylori

Question 3

What are the 3 stages of digestion?

Answer 3

1) Cephalic 2) Gastric 3) Intestinal

Question 4

What normally prevents gastric acid from refluxing into the oesophagus?

Answer 4

Lower oesophageal sphincter

Question 5

What is the normal resting pressure of the lower oesophageal sphincter and how do we measure that?

Answer 5

Approximately 30mmHg, measured using manometry.

Question 6

Why does acid cause damage to the oesophageal mucosa but not to the gastric mucosa?

Answer 6

The oesophagus is squamous cells that are sensitive to acid. The stomach/gastric mucosa is columnar cells which protect against acid.

Question 7

What is Barrett’s oesophagus?

Answer 7

Pre-malignant changes in the oesophagus. 0.5% chance per annum of contracting cancer. Treat using acid suppression and regular endoscopes.

Question 8

What is Nissen fundoplication?

Answer 8

An invasive surgical procedure used to treat reflux disease. It causes dysphagia for weeks, normally wears off but is persistent in around 3% of patients. Patients who have it can’t burp which leads to gas bloating.

Question 9

How do histamine 2 receptor antagonists work?

Answer 9

ECL cells release histamine which binds to histamine 2 receptors on parietal cells which causes the release of gastric acid. H2r antagonists competitively inhibits the histamine 2 receptor on parietal cells so less acid is secreted.

Question 10

Name two histamine 2 receptor antagonists and state by what percentage they decrease gastric acid secretion.

Answer 10

• Cimetidine (Tagamet)
• Rantidine (Zantac)
• They reduce gastric acid secretion by approx. 60% but if used long term their inhibitory efficacy is reduced.

Question 11

How long do PPIs inhibit acid for after a single dose?

Answer 11

24-48 hours.

Question 12

By what percentage do PPIs inhibit gastric acid secretion?

Answer 12

90% or more.

Question 13

How do PPIs avoid being activated in the stomach?

Answer 13

They have a special coating on them which prevents them being activated the gastric mucosa and so allows it to travel in the systemic circulation to the proton pump/

Question 14

When should PPIs be taken and why is this important?

Answer 14

Approx. 30 minutes before a meal. This is done so that the meal will be stimulating the activity of the proton pump at a time when the proton pump inhibitor is active. This is important as the drug is only active against activated proton pumps.

Question 15

What is the treatment for H. pylori infection?

Answer 15

A triple therapy involving a PPI and 2/3 of the following antibiotics: amoxycillin, clarithromycin and metronidazole. Taken for a week and eliminates 80% of infections.

Question 16

How do you treat peptic ulcers caused by NSAIDs?

Answer 16

Stop the NSAID and heal with a PPI. Selective cox-II inhibitors have slightly less risk than non-selective NSAIDs. Occasionally, prostaglandin analogues such as Misoprostil (Cytotec) may be used along with NSAIDs to reduce their mucosal ulceration.

Question 17

What type of epithelium is found in places where there is friction?

Answer 17

Stratified squamous epithelium.

Question 18

What is atrophic gastritis?

Answer 18

A process of chronic inflammation of the stomach mucosa, leading to loss of gastric glandular cells and their replacement by intestinal and fibrous tissues.

Question 19

What is gastro-oesophageal reflux disease?

Answer 19

Retrograde passage of acidic gastric contents into oesophagus. Symptoms include: heartburn, regurgitation, dyspepsia, nausea and more.

Question 20

What is the angle of His?

Answer 20

Acute angle created between the cardia of the stomach and the oesophagus that prevents reflux.

Question 21

What is a hiatus hernia?

Answer 21

Protrusion of part of the stomach through the diaphragmatic hiatus and into the chest. Two types: sliding (80%): gastro-oesophageal junction slides through hiatus. Rolling: fundus of the stomach protrudes through hiatus alongside gastro-oesophageal junction.

Question 22

How do prokinetics works?

Answer 22

They increase gastric emptying and increase lower oesophageal pressure. eg. Metoclopramide.

Question 23

What is tachyphlaxis?

Answer 23

A rapid decrease in the response to a drug due to previous (long-term) exposure to that drug.

Question 24

What is a Curling’s ulcer?

Answer 24

A type of stress ulcer, an acute gastric erosion resulting as a complication from severe burns when reduced plasma volume leads to ischemia and cell necrosis (sloughing) of the gastric mucosa.