GIT pathology

Question 1

What are the 4 layers within a chronic peptic ulcer

Answer 1

• Exudate of fibrin, neutrophils and necrotic debris
  
  • Narrow zone of fibrinoid necrosis
  • Zone of cellular granulation tissue
  • Zone of fibrosis

Question 2

What are complications of chronic peptic ulcers

Answer 2

• Perforation leading to peritonitis
  
  • Haemorrhage
    
    • Aneamia
  • Penetration and erosion of adjacent organs
  • Stenosis from scarring

Question 3

What effects do PGE2 have on the gastric system (5)

Answer 3

inhibit acid secretion, stimulate HCO3- and mucus secretions, increase mucosal blood flow and modify local inflammation

Question 4

What effects occur in response to histamine in acute gastritis

Answer 4

Can promote acute inflammation, oedema, neutrophil recruitment, fluid and blood into lumen, damage of muscosal and epithelial barriers (enterocytes). This can then lead to acid mediated damage, necrosis and superficial erosion (epithelial layer only).

Question 5

How long do acute ulcers take to heal

Answer 5

Take around 3-4 days to heal after insult as the cells are able to be turned over very quickly. If not healed then can lead to superficial chronic gasrtitis

Question 6

What can induce acute gastrritis

Answer 6

Alcohol, NSAIDs, bile, H.pylori and Aspirin. However can be caused by reduced bloodd flow that can be seen after shock, sepsis and trauma

Question 7

How do acute peptic ulcers form

Answer 7

extension of erosions

Question 8

What are the three types of chronic gastritis

Answer 8

Autoimmune, Bacterial and Chemicals

Question 9

What are the targets in Autoimmune gastritis

Answer 9

parietal cells, H+/K+ pumps in the antrum and can lead to ECL hypertrophy and carcinodosis

Question 10

Consequences of Autoimmune gastritis

Answer 10

Total atrophy of acid secreting cells, replaced by intestinal metaplasia accompanied by chronic inflammation. May cause development of cancer

Question 11

Common chemicals that induce chroni gastritis

Answer 11

Aspirin, NSAIDs, refluxed bile and alkaline juice

Question 12

What is the consequence of chemicals

Answer 12

Cause desruption of the mucousal layers of the stomach and gastric barriers causing direct damage to the enterocytes leading to epithelial desquamination. Leads to mucus cell hyperplasia with elongation and tortuosity of gastric pits, vasodilation, oedema and fibromuscular hyperplasia of LP and mild imflammatory infiltrate
Intestinal metaplasia and erosions can occur.

Question 13

What are the bacterial causes of Chronic gastritis

Answer 13

H. pylori

Question 14

How does H. pylori cause disease

Answer 14

invades into the mucosa layer and adheres to the enterocytes at their junctions leading to their breakdown. Muscus layer not as efective and breaksdown, leading to acid mediated damge of the enterocytes and below. This leads to a neutrophil response, and an acute inflammation

Question 15

Histological changes seen in H/ Pylori infections

Answer 15

• Foveolar hyperplasia
• Intestinal metaplasia
• Neutrophil infiltrate
• Erosions and acute peptic ulcers
• Parietal cell hyperplasia

Question 16

What is the Human gastric cancer sequence

Answer 16

Chronic gastritis
atrophic gastritis
Intestinal metaplasia
dysplasia
Adenocarcinoma

Question 17

Long term complocations of H. Pylori infections

Answer 17

• Gastric mucosal atrophy and intestinal metaplasia leading to gastric adenocarcinoma
• Gastric Ulcer
• B-cell lymphoma of MALT

Question 18

Why can the duodenum be invaded by H.pylori

Answer 18

HCl damage induces gastric foveolar cell metaplasia leading to colonisation as the D1 region now looks like body of stomach

Question 19

What are the ratios of D1:Stomach body h pylori infections

Answer 19

4:1

Question 20

What are the different classifications of peptic ulcers

Answer 20

erosion - superficual only
Acute ulcer - through the muscularis mucosae
Chronic ulcer - through the muscularis propria with associated fibrosis

Question 21

What is the response of the omentum to perforation

Answer 21

Will aim to cover and prevent bleed

Question 22

What gene is mutated in Signet ring cell carcinoma and who is predisposed

Answer 22

Adhesion proteins are mutated and most commonly seen in women under 45

Question 23

What is the definition of acute gastritis

Answer 23

Acute gastritis is a transient mucosal inflammatory process that is caused by a deficiency in the mucosal protection of enterocytes

Question 24

What is the definition of chronic gastritis

Answer 24

Is a less severe yet more persistent form of acute gastritis, most common cause if H.pylori

Question 25

What is Peptic ulcer disease

Answer 25

Is a consequence of acute or chronic gastritis in which the integrity of enterocytes is compromised to acidic nature of the lumen and can result in intestinal metaplasia and adenocarcinoma formation