Disorders of gastric secretion

Question 1

What is a peptic ulcer?

Answer 1

Open sore on the lining of the oesophagus, stomach or duodenum due to breakage of mucosal barrier and exposure of tissues to erosive effects of HCl, pepsin and bile acids

Question 2

What are the symptoms of peptic ulcer?

Answer 2

nausea
anorexia
anaemia
black, tarry stools
chest discomfort
epigastric pain
vomiting blood
dyspepsia (indigestion)

Question 3

Where are peptic ulcers common?

Answer 3

Duodenal Cap
Stomach
Distal Oesophagus (especially in Barrett's oesophagus)
Meckel's diverticulum
After a gastroenterostomy

Question 4

What are the causes of peptic ulcers?

Answer 4

Hyperacidity- reflux of duodenal contents

H.pylori- risk factor for peptic ulcers and gastric cancer

NSAIDs- aspirin

Genetic Factors

Sex- being male

Question 5

What is the general outcome of a peptic ulcer?

Answer 5

Complete healing and replacement of tissue with some scarring

Question 6

Describe chronic peptic ulcer.

Answer 6

Common and occur in upper GIT

Asymptomatic in more than 80 % of people

Inflammation plays a key role in the disease process

Question 7

Describe an acute peptic ulcer.

Answer 7

Less frequent

Develop from areas of corrosive gastritis (oesophagus, stomach, proximal duodenum).

Also develops from severe stress or shock (burns, trauma)

There is acute hypoxia of the surface epithelium (ischaemia of gastric mucosa)

Outcomes are:

• severe bleeding
• heal with no scarring
• chronic peptic ulcer

Question 8

What factors prevent infection of the gastric mucosa?

Answer 8

• HCl
• Pepsin
• Mucus
• Peristalsis and fluid movement
• Seamless epithelium with tight junctions
• Fast cell turnover
• IgA secretion at mucosal surfaces
• Peyer’s patches

Question 9

What is Helicobacter pylori (H. pylori)?

Answer 9

Gram-negative, spiral shaped (can be coccoid) aerobic bacterium which penetrates gastric mucosa and is able to survive under harsh conditions of the stomach

highly pathogenic with many virulence factors which enable it to attach and colonise the gastric epithelium

Question 10

Give the virulence factors of H.Pyruli.

Answer 10

• Flagella enables motility towards gut epithelium
• Produces urease enzyme, which converts urea to ammonia, which buffers gastric acid and produces CO2
• Cytotoxin Associated Antigen inserts pathogenicity islands and confers ulcer forming potential
• Vacuolating Toxin A alters the trafficking of intracellular protein in gastric cells
• Large number of outer membrane proteins e.g. Adhesins (Bab A), phospholipases, porins, iron transporters, and flagellum-associated proteins

Question 11

What is the Effect of H.pylori on D and G cells?

Answer 11

Decreases number of D and G cells, decreasing somatostatin and gastrin release, therefore increasing gastric acid secretion

*Gastrin not only way gastric acid released

Question 12

What are the Diagnostic Tests for peptic ulcer?

Answer 12

Endoscopy (oesophagogastroduodenoscopy)

Histological Examination

Question 13

What are the Tests for the presence of H.pylori?

Answer 13

Stool antigen test

Evaluate urease activity

urea breath test

Question 14

What are the Complications of Peptic Ulcer?

Answer 14

Haemorrhage (GI bleeding)

Perforation (peritonitis) and penetration (liver and pancreas may be affected)

Pyloric stenosis or oesophageal stenosis

Malignant change becomes 3-6 times more likely with H.pylori infection