Upper GI physiology and gastric disease

Question 1

Factors in gastric emptying

Answer 1

Fast emptying:

• Water or glucose
• Low calorie and liquid

Moderate emptying:

• High calorie liquid
• Homogenized solids

Slow emptying:

• Low fat solid meal
• High fat solid meal

Question 2

What does a G cell produce?

Answer 2

Gastrin

Regulates gastric H+

Question 3

What does a parietal cell produce?

Answer 3

HCl, intrinsic factor and grelin

HCl= acid
IF = B12 absorption
Grelin = hunger signalling

Question 4

What is the role of cholecystokinin?

Answer 4

Regulates pancreatic enzyme secretion

Question 5

Stimulation of gastric acid production?

Answer 5

3 signalling pathways:

• Gastrin
• Histamine
• ACh

Gastrin –> CCK-B receptor –> Ca –> H/K/ATPase channel
Histamine –> H2 receptor –> cAMP –> Ca –> H/K/ATPase channel
ACh –> M3 receptor –> Ca –> H/K/ATPase channel

Question 6

Treatment of acid overproduction

Answer 6

PPIs

H2 receptor antagonists

Question 7

Side Effects of PPIs

Answer 7

Pneumonia
Gastroenteritis
Osteoporosis
C. Difficile infections
Acute interstitial nephritis
Atrophic gastritis
Hypomagnesaemia
Pseudomembranous colitis

Question 8

Causes of hypergastrinaemia?

Answer 8

Prolonged acid inhibition - PPIs and H2RAs

Atrophic gastritis

• Pernicious anaemia
• H. pylori

Vagotomy/SB resection

Gastrin secreting tumours
Renal failure
Hypercalcaemia

Question 9

Zollinger Ellison Syndrome

Answer 9

1/3rd have MEN 1 - MENIN 1 chromosome 11

Diagnosis:

• Fasting gastrin >1000
• PET-CT

Question 10

Most sensitive test for pernicious anaemia?

Answer 10

Fasting gastrin level

Question 11

Motility disorders associated with loss of interstitial cell of Cajal

Answer 11

Slow transit constipation
Internal anal sphincter achalasia
Gastroparesis
Crohns
Chagas
Achalasia

Question 12

Important H pylori virulance factor?

Answer 12

Cag A

• -> more duodenal ulcers
• –> Worse gastritis
• -> higher relapse rate
• -> ? less cancer

Question 13

Patterns of Gastritis?

Answer 13

Antrum predominant:

• -> Chronic inflammation of the antrum and pylorus
• -> Increased acid production
• -> Chronic inflammation and gastric metaplasia of the duodenuem
• -> Duodenal ulceration

Pangastritis:

• -> Chronic inflammation of the entire stomach
• -> Intestinal metaplasia of the stomach
• -> Reduced acid production
• -> Gastric ulceration

Question 14

Why treat H. Pylori?

Answer 14

Eradication of H. Pylori results in long term remission of peptic ulcer disease

Question 15

Antibiotic resistance and H. Pylori

Answer 15

Metronizaole resistance

Clarithomycin resistance rising