CSIM 1.50: Gastrointestinal Inflammation

Question 1

What is secreted at the stomach?

Answer 1

• Acid
  
  • Pepsinogen
  • Intrinsic factor (B12 absorption)

Question 2

Which cells;

1) secrete acid?
2) secrete pepsinogen?
3) Secrete intrinsic factor?

Answer 2

1) Parietal cells
2) Chief cells
3) Parietal cells

Question 3

What can cause acute gastritis?

Answer 3

ABC:
  •  Autoimmune
  •  Bacterial (H. pylori)
  •  Chemical 
  •  Vascular damage
  •  Alcohol

Question 4

What are the symptoms of acute gastritis?

Answer 4

• Abdominal pain

* Vomiting/Haematemesis

Question 5

What are the chemical causes of acute gastritis?

Answer 5

• Bile and bicarbonate reflux into the stomach
  
  • Disorganised motility
  • Gallstones

Question 6

What condition is associated with autoimmune gastritis? Why?

Answer 6

Associated with macrocytic (PERNICIOUS) anaemia
• Parietal cells damaged
• No intrinsic factor produced
• B12 cannot be absorbed
• Macrocytic anaemia as the cell grows but DNA cannot replicate

Question 7

What does H. pylori secrete to protect it from the harsh environment of the gut?

Answer 7

• Urease

* Phospholipase

Question 8

How is the damage to the mucosa caused in bacterial gastritis?

Answer 8

• Toxins produced by the bacteria

* Lymphocytes and polymorphs from the host immune response damage the mucosa

Question 9

Describe the progression of gastritis regardless of cause, if left untreated

Answer 9

Chronic gastritis leads to ATROPHIC GASTRITIS:

• Atrophy occurs, where parietal cells die, and fibrosis occurs
• Digestion is impaired, as there is a loss of H+ and intrinsic factor secretion (parietal cells)
• The gastric epithelium undergoes intestinal metaplasia due to the change in microenvironment
• ECL cells undergo hyperplasia, which lead to a carcinoid tumour

Question 10

Describe the metaplasia seen in chronic gastritis

Answer 10

Gastric cells become:
• Small bowel cells first (absorptive)
• Then colonic

Question 11

What is ulceration? What is the commonest cause when found in the:

1) Upper GI?
2) Small bowel?
3) Colon?

How does ulceration differ from erosion?

Answer 11

A breach in the mucosa which extends through the muscularis mucosa into the submucoa+

1) Peptic ulceration
2) Crohn’s disease
3) Ulcerative colitis

Erosion constitutes damage to the muscularis mucosa only (far more superficial)

Question 12

What causes acute peptic ulceration?

Answer 12

• Chemical injury
  
  • Severe stress

NB: NOT H. pylori, as this can only cause ulceration chronically

Question 13

What are the major complications associated with ulcers?

Answer 13

• Haemorrhage (20%)
  
  • Perforation of adjacent organs (perforates into the liver)
  • Stenosis and stricture of lumen due to fibrosis (IMG 120)

Question 14

Where are peptic ulcers found?

Answer 14

• Antrum of stomach

* First part of duodenum

Question 15

What is Zollinger Ellison syndrome?

Answer 15

Gastrin-producing tumours, which can cause peptic ulcers

Question 16

Describe the histology of an ulcer

Answer 16

From superficial to deep:
• Top layer of exudate and necrotic tissue
• Granulation tissue (inflammed, vascular repair tissue)
• Fibrous tissue

IMG 118

Question 17

What causes chronic oesophagitis?

Answer 17

Reflux due to:
  •  Defective LOS
  •  Hiatus hernia
  •  Gastric surgery
Other rare causes:
  •  Crohn's disease
  •  TB

Question 18

Describe the morphological changes seen in chronic reflux oesophagitis

Answer 18

• Basal cell hyperplasia
  
  • Elongation of papillae
  • Lymphocytes and eosinophils in the epithelium

Question 19

What are the complications of chronic oesophagitis?

Answer 19

• Haemorrhage
  
  • Perforation
  • Fibrosis and stricture
  • Barrett’s oesophagus

Question 20

What is visible in Barrett’s oesophagus?

Answer 20

• Squamo-columnar junction
  
  • Gastro-oesophagal junction

IMG 119

Question 21

How do patients with Crohn’s disease present?

Answer 21

• abdominal pain
  
  • fever
  • diarrhoea

Question 22

Where does Crohn’s affect and what pattern is seen?

Answer 22

Usually the colon, but can be any part of the GI tract from mouth to anus -

The inflammation is:
• DISCONTINUOUS/PATCHY
• Transmural (all the way through when viewed in cross section- not just lumen)
• Fissuring ulceration

Question 23

What is the most common inflammation seen in Crohn’s?

Answer 23

Terminal ileitis

Question 24

How is Crohn’s disease differentiated from ulcerative colitis?

Answer 24

• UC only seen in colon
  
  • Granuloma seen in Crohn’s
  • Discontinuous and transmural inflammation in Crohn’s with fissuring ulceration
  • UC does not lead to strictures

Question 25

What are the complications of Crohn’s?

Answer 25

• Fistulae (bowel, skin, bladder, vagina)
  
  • Loss of protein
  • Malabsorption
  • Bowel cancer

Question 26

How does ulcerative colitis present?

Answer 26

• Bloody diarrhoea

Question 27

What gene is associated with Crohn’s disease?

Answer 27

NOD 2 gene

Question 28

Describe the pattern/distribution of UC

Answer 28

• Distal colon
  
  • Uniform (not patchy, continuous)
  • Confined to lamina propria mucosa (not transmural)
  • Glands destroyed

NB: in severe cases, can cause backwash ileitis

Question 29

Describe the acute and chronic phase of ulcerative colitis

Answer 29

Acute phase:
• Red and friable
• Ulcerations
• Pseudopolyps (undermining ulceration, causing a ‘mushroom’) IMG 121

Chronic phase:
• Shortening of colon
• Loss of normal mucosal folda

Question 30

What happens to the vasculature in UC?

Answer 30

It becomes congested

Question 31

What are the main complications of UC?

Answer 31

• Toxic megacolon

* Polyps (dysplasia -> malignancy)