Pathophysiology of gastric disease

Question 1

What is GORD?

Answer 1

Gastro oesophageal reflux disease

Question 2

What are the symptoms of GORD?

Answer 2

• Chest pain
• Acidic taste in mouth
• Cough

Question 3

What kind of things will trigger GORD?

Answer 3

• Obesity
• Pregnancy
• Hiatus Hernia
• LOS function
• Delayed gastric emptying

Question 4

What are some of the possible consequences of GORD?

Answer 4

• Nothing
• Oesophagitis
• Strictures → causes vomiting everytime you swallow
• Barret’s oesophagus→ metaplasia of oesphagus

Question 5

What is Barret’s Oesophagus?

Answer 5

Metaplasia of the stratified squamous epithelia → simple columnar epithelia → can lead to an adenocarcinoma

Question 6

What components make up to the Lower Oesophageal Sphincter?

Answer 6

• Muscular element
• Right crus of diaphragm (loops around oesophagus)
• Oesphagus angled entry to stomach
• Intra abdominal pressure

All act together to contract around the oesophagus

Question 7

When is pressure around the LOS highest and lowest?

Answer 7

Highest at night

Lowest after meals

Question 8

How would you treat someone with GORD?

Answer 8

• Lifestyle modification → eat slower, smaller meals, lose weight
• Pharmacological
  
  • Antacids → add a layer on top of the stomach
  • H₂ antagonists → stop parietal cell release of H⁺
  • Proton Pump inhibitos
• Surgery - rare!

Question 9

What is a hiatal hernia and how can this lead to GORD?

Answer 9

A hernia where part of the stomach slips above the diaphragm

Mechanism relating to GORD not fully understood:

• Loss of intra abdominal pressure creating basal tone
• Don’t get the increase in LOS tone when straining

Question 10

What is Gastritis?

Answer 10

Inflammation of the protective lining of the stomach (stomach mucosa)

Question 11

What symptoms might present if someones suffering with gastritis?

Answer 11

• pain
• nausea
• vomiting
• bleeding

Question 12

What kind of things will cause acute gastritis?

Answer 12

• Heavy use of NSAIDs
• Lots of alcohol- dissolves mucus lining
• Chemotherapy
• Bile reflux into the stomach

Any chemical injury damages stomach epithelia and reduces mucus production. Mucosa responds by vasodilation/ oedema and inflmmatory cells

Question 13

How do you treat acute gastritis?

Answer 13

Remove the stimulus

Question 14

What is chronic gastris and how can it be divided?

Answer 14

Perisitant stomach inflammation

1. Bacterial
2. Autoimmune

Question 15

Explain what happen in autoimmune gastritis and what some of the consequences can be

Answer 15

Autoantibodies are made to gastric parietal cells, affects the fundus but spares the antrum

• Can lead to pernicious anemia (B₁₂ deficiency anaemia) as parietal cells produce intrici factor for B₁₂ absorption and acid for iron absorption
• B₁₂ deficiency can lead to glossitis
• Anorexia as painful to eat
• neurological symptoms

Question 16

What is the most common cause of bacterial, chronic gastritis?

Answer 16

Heliobacter Pylori

Question 17

Give some of the features of H. Pylori organism

Answer 17

• Helix, gram negative, microaerophilic
• Spread feaco-orally
• Produces urease → converts urea to ammonium and increases local pH
• Flagellum gives good motility and allows adhesion to mucus layer so remains in stomach

Question 18

What problems does helicobacter pylori cause?

Answer 18

• Releases cytotoxins causing direct epithalial injury
• Expresses urease producing ammonia whic is toxic to epithelia
• Can degrade the mucus layer
• Promotes inflammatory response

Question 19

How does the location of H. pylori affect the effect it has on the stomach?

Answer 19

Antrum colonisation only: affects G cells, increasing gastrin secretion. Increased parietal cell acid secretion

Can cause duodenal epithelial metaplasia and ulceration if colonises the duodenum

If in the antrum and body: effects cancel and the patient is asymptomatic

If predominantly in body: causes atrophy effect, stomach shrinks making breakdown and ulceration a lot easier → leads to intestinal metaplasia and potentially cancer

Question 20

How would you diagnose Helicobacter pylori?

Answer 20

• Urea breath test using carbon 13
• Stool antigen test
• Can use upper GI endoscopy if needed

Question 21

How would you treat a patient who has helicobacter pylori?

Answer 21

• Proton Pump inhibiotrs
• Amoxicillin + (clarithromycin or metronidazole)

Question 22

Define Peptic ulcer disease

Answer 22

Defect in the gastric/ duodenal mucosa that extends through muscularis mucosa

Commonly affects lesser curve/ antrum of stomach and first part of duodenum

Question 23

Compare and contrast gastric ulcers and duodenal ulcers based on:

incidence, age distribution, social class, blood group, acid evels and H.pylori gastritis

Answer 23

Question 24

What are the normal defence mechanisms of the stomach?

Answer 24

• Mucus
• Bicarbonate
• Adequate mucosal blood flow to remove acid that diffuses through injured mucosa
• Prostaglandins
• Epithelial renewal

Question 25

Why is the breakdown of normal stomach defences, more important than excessive acid in peptic ulcer disease?

Answer 25

Ulcers can develop in people with any level of acid; normal or low Rpaid gastric emptying/ inadequare neutralisation from the bile/ pancreas is more implicated in duodenal ulcers

Question 26

What things can cause mucosal injury, leading to peptic ulcer disease?

Answer 26

* H. Pylori * NSAIDs * Smoking (more involved in **relapse** than initial insult) * Major physiological stress e.g. burns

Question 27

Where do chronic peptic ulcers most frequently occur?

Answer 27

At **mucosal junctions** e.g. where antrum meeds body and where antrum meets duodenum

Question 28

Describe the morphology of peptic ulcers

Answer 28

* Generally \<2cm * Base of ulcer is **necrotic/ granulation** tissue * Muscularis propria can be replaced by **scar tissue**

Question 29

What are some of the clinical consequences of peptic ulcer disease?

Answer 29

* Narrowing of stomach due to repeated scar tissue * Perforation causing peritonitis * Erosion of adjacent structures (liver or pancreas) * Heamorrhage * Malignancy (rare)

Question 30

Give some of the symptoms of peptic ulcer disease

Answer 30

* Epigastric pain, sometimes moving to the back * burning/ gnawing * pain often follows meal times * pain often at night

Question 31

What are some of the **serious** symptoms of peptic ulcer disease?

Answer 31

* Haematemesis (vomiting blood) or malaena (dark stools) * Early satiety - from repeated scarring narrowing lumen * Weight loss - as reluctant to eat

Question 32

How do you manage someone with peptic ulcer disease?

Answer 32

* lifestyle modification- avoids foods making it worse * Stop exacerbating medications * Test for H. pylori and eradicate if present * PPI's * Endoscopy

Question 33

What is **functional dyspepsia**?

Answer 33

When someone present with the **symptoms** of ulcer disease but there is **no physical evidence** of organic disease

Question 34

What is **Zollinger- Ellison** syndrome?

Answer 34

A non beta islet cell **gastrin** secreting tumour of the pancreas Consequence: * proliferation of parietal cells → lots of acid production * Causes severe **ulceration** of stomach and small bowel * Symtpoms of abdominal pain and diarrhoea

Question 35

What is stress related mucosal damage?

Answer 35

Broad term to describe pathology attributed to acute, erosive, inflammatory insult to the upper GI tract associated with critical illness: * Severe burns * raised intracranial pressure * sepsis * severe trauma * multiple organ failure

Question 36

What are some of the featurs of stomach cancer?

Answer 36

Has to be quite a **large cancer** before symptoms present * dysphagia * loss of appetite * malaena * weight loss * nausea/ vomiting * Virchow's nodes

Question 37

What are some of the risk factors for developing stomach cancer?

Answer 37

* Male * H. pylori * Dietary factors * Smoking