GIT - stomach

Question 1

diseases of the stomach

congenital (2) and acquired (6)

Answer 1

congenital

• diaphragmatic hernia
• pyloric stenosis

acquired

• gastropathy
• acute gastritis
• chronic gastritis
• peptic ulcer (PUD)
• neoplasm
• uncommon forms of gastritis (eosinophilic, lymphocytic, granulomatous)

Question 2

gastropathy definition

Answer 2

inflammation of gastric mucosa

absence of inflammatory cells

Question 3

acute gastritis

+ symptoms

Answer 3

inflammation of gastric mucosa
presence of neutrophils
causes superficial erosions and gastric ulcers
cause congestion also -> petechial hemorrhage / erosions

symptoms: epigastric pain, indigestion, n/v, bleeding
may be asymptomatic also

Question 4

causes of acute gastritis/gastropathy (6)

Answer 4

• reflux - alcohol, bile
• drugs: NSAIDs
• cigarettes
• chemo/radiation therapy
• stress-induced mucosal injury: sepsis/ trauma/ burns/ cushing’s (cause intracranial disease?)
• uremia

Question 5

pathogenesis of acute gastritis/gastropathy

Answer 5

• NSAIDs: inhibit COX dependent synthesis of prostaglandins - prostaglandins are the one that stimulate defence mechanisms in stomach
• chemo/radiation therapy + chemicals/alcohol/cigarettes: direct injury to mucosal epithelium and stroma cells
• stress-induced mucosal injury: results in local ischemia
  cushing’s cause IC disease stimulates vagal nuclei -> hypersecretion of acid
• uremia: inhibits gastric bicarbonate transporters

Question 6

chronic gastritis pathogenesis

Answer 6

Chronic mucosal inflammation -> mucosal atrophy and intestinal metaplasia
metaplasia -> carcinoma

Question 7

chronic gastritis forms (2)

Answer 7

• associated chronic gastritis: H.pylori**

- autoimmune gastritis

Question 8

H.pylori

- diseases associated (4)

Answer 8

most common cause of chronic gastritis
asymptomatic

diseases associated:

• Chronic gastritis
• Peptic ulcer
• Gastric carcinoma
• Gastric lymphoma

Question 9

H.pylori associated chronic gastritis characteristics

Answer 9

• active inflammation: inflammatory cells (neutrophils, lymphocytes, lymphoid aggregates)
• regenerative changes: epithelium undergoes mitosis
• eptithelium metaplasia (now looks like intestines)
• atrophy: loss in glands
• may undergo dysplasia -> invasive adenocarcinoma

Question 10

H.pylori diagnosis

Answer 10

• urea breath test: H/pylori produces urease which breaks down the urea -> radioactive CO2 detected in breath
  CO2 detected = pos of H.pylori infection
• serology
• histology
• culture: curved microaerophilic organism

Question 11

autoimmune gastritis (chronic gastritis)

Answer 11

rarer (<10%)

• Diffuse gastritis of oxyntic mucosa (in body and fundus of stomach)
• > antibodies to gastric parietal cells and intrinsic factor can be detected in serum/gastric secretions
• extensive intestinal metaplasia and pseudopyloric metaplasia
• severe gastric body-fundal atrophy

Question 12

effects of autoimmune gastritis (4)

Answer 12

• Defective gastric acid secretion – hypo- or achlorhyridia
• Endocrine cell hyperplasia - hypergastrinemia
  associated w/ endocrine disorders: hashimoto’s/graves/DM
• Disabled ileal Vit B12 absorption - Megaloblastic anemia
• Chief cell destruction - reduced serum pepsinogen I concentration

could lead to Pernicious anemia (vit B12 def), adenocarcinoma, carcinoid tumor

Question 13

peptic ulcer disease (PUD)

Answer 13

chronic mucosal ulceration affecting the duodenum or stomach
- more common in 1st part of duodenum
- affects lesser curve of stomach
penetrates muscularis mucosae

Question 14

other rarer PUD caused diseases

Answer 14

Heterotopic gastric mucosa - at merkel diverticulum (umbilical cord remains that cause an outpouching)

Question 15

risk factors/ causes of PUD

Answer 15

• H,pylori
• cigarettes
• COPD
• drugs that reduce mucosal blood flow (cocaine)
• NSAIDs
• alcohol -> alcoholic cirrhosis
• psychological stress - increase gastric acid secretion
• Endocrine hyperplasia - stimulate parietal cell growth
• Zollinger-Ellison syndrome in distal duodenum

Question 16

H.pylori -> PUD pathogenesis**

Answer 16

produce urease, protease & phospholipases:

• Urease: generates NH3 and CO2 from endogenous urea. NH3 inhibits bicarbonate channels -> decrease bicarbonate secretion
• Protease: breaks down glycoprotein in gastric mucosa
• Phospholipases: damage epithelial cells -> thrombotic occlusion of capillaries

inflammatory effects:
attracts neutrophils - release myeloperoxidase -> damages mucosa -> leakage of tissue nutrients

Question 17

gross PUD appearance

Answer 17

• ‘punched out’ defect
• Base is smooth and clean
• Scarring and puckering of the wall

Question 18

PUD clinical symptoms

Answer 18

• Epigastric burning or aching pain
  Pain tends to occur 1-3 hours after meals during the day and worse at night. Relieved by alkali or food
• Nausea, vomiting bloating belching, weight loss
• anemia, hemorrhage and perforation

Question 19

PUD complications

Answer 19

• bleeding (most common)
• perforation
• obstruction
• gastric adenocarcinoma

Question 20

causes of upper GIT bleeding

Answer 20

• duodenal/gastric ulcers
• gastric erosion
• esophageal varices
• Mallory-Weiss tear: tear of tissue in lower esophagus - caused by violent coughing/vomiting
• esophagitis
• erosive duodenitis
• neoplasm

Question 21

microscopic PUD appearance (4 features)

Answer 21

• fibrinopurulent exudate
• necrotic debris
• granulation tissue
• fibrinosis

Question 22

definition of intestinal metaplasia

Answer 22

Change of gastric columnar mucosa to that of intestinal type (with goblet cells)

Question 23

definition of dysplasia

Answer 23

Pre-malignant / neoplastic changes of the gastric mucosa - w/ potential for further steps in malignant transformation

Question 24

stomach defense mechanism

Answer 24

• thick mucosal layer
• epithelial mucous producing cells
  secrete bicarbonate and mucus -> neutralise stomach acidity + pepsin

Question 25

intestinal metaplasia clinical symptoms

Answer 25

- black tarry stools cause of hemorrhage - altered bowel movement: constipation, nausea/vomitting - pain in epigastrium