Met: PBL 3 (GORD/Heartburn)

Question 1

Define ‘heartburn’

Answer 1

Form of indigestion pain felt as a burning sensation in the chest, caused by acid regurgitation into the oesophagus from the stomach

Question 2

Define ‘dysphagia’

Answer 2

Difficulty swallowing

Question 3

What is helicobacter pylori?

Answer 3

An organism found in the stomach and duodenum of many people with peptic ulcers,

Question 4

What is a urea breath test used to diagnose?

Answer 4

An individual has to drink a substance containing urea, if H. Pylori is present it has a urease enzyme that will convert the urea to carbon dioxide and nitrogen, the CO2 is then absorbed through the stomach into the blood, and therefore exhaled. Therefore, the individual is asked to breathe into a bag which is sent for lab testing to look for the quantities of CO2, if large this is indicative of H. Pylori infection

Question 5

What is gastroparesis?

Answer 5

Where the stomach takes longer than normal to dispose of stomach acid

Question 6

How may being pregnant increase your risk of acid reflux?

Answer 6

The change in hormone levels during pregnancy may weaken the LOS and the increased stomach pressure can push the gastric contents back up the oesophagus

Question 7

Outline some of the risk factors for gastro-oesophageal reflux disease

Answer 7

Obesity (pressure on abdomen), eating lots of fatty food (takes longer to dispose of stomach acid), smoking/coffee/chocolate/alcohol (may relax LOS), hiatus hernia, stress, gastroparesis

Question 8

Outline two medications which can lead to GORD symptoms

Answer 8

Calcium channel blockers (treat hypertension) and nitrates (treat angina) as these can relax the LOS

Question 9

Outline four medications that can contribute to the development of oesophagitis

Answer 9

NSAIDs (includes ibuprofen), SSRIs (type of antidepressant), corticosteroids (treats severe inflammation), bisphosphonates (treat osteoporosis)

Question 10

What is oesophagitis?

Answer 10

Where stomach acid irritates and inflames the lining of the oesophagus

Question 11

What is the lower oesophageal sphincter (LOS)?

Answer 11

Ring of muscle at the bottom of the oesophagus which works as a valve to let food into your stomach to be digested by acid, and closes to prevent any acid leaking back up into the oesophagus

Question 12

What is the cause of the symptoms associated with GORD?

Answer 12

The movement of acid back up into the oesophagus when the LOS has been weakened

Question 13

Why is acid reflux proposed to be a vicious cycle?

Answer 13

Reflux can lead to scarring, and the scarring can cause damage to the LOS, leading to ability for more acid to move up the oesophagus, worsening the reflux/GORD each time

Question 14

Define ‘acid reflux’

Answer 14

Where acid is regurgitated into the throat or mouth, usually causing a sour taste at the top of the throat or back of the mouth

Question 15

Name the treatments for GORD/acid reflux

Answer 15

antacids, H2 antagonists, PPIs

Question 16

When may further investigations be required in someone who presents with symptoms of reflux?

Answer 16

If they have pain when they swallow, have difficulty swallowing OR when symptoms don’t improve with medication

Question 17

What is Barrett’s oesophagus?

Answer 17

When the oesophageal epithelium undergoes metaplasia from stratified squamous to simple columnar and this increases the risk of oesophageal cancer largely

Question 18

How can acid reflux lead to iron-deficiency or anaemia?

Answer 18

Can cause bleeding where the irritation or scarring is due to small blood vessels beneath being damaged, bleeding is in small amounts but these can lead to a level of iron-deficiency or anaemia due to blood loss here

Question 19

What is the mechanism of alginates in the treatment of GORD?

Answer 19

They form a ‘raft’ that floats on the surface of the stomach contents and reduces reflux and protects the oesophageal mucosa

Question 20

What are potential treatment options for dysphagia?

Answer 20

Surgery to wide oesophagus, diet changed to more liquid food, fed by tube, speech therapy to develop different swallowing techniques

Question 21

Describe the mechanism of action of antacids in the treatment of reflux

Answer 21

Contain alkaline ions (e.g. calcium/magnesium carbonate) which chemically neutralise the stomach acid contents

Question 22

Describe the mechanism of action of H2 receptor antagonists in reflux

Answer 22

Histamine binds to H2 receptors to cause acid production by parietal cells, so blocking this receptor reduces the stimulation of acid production so less gastric acid is secreted HOWEVER, doesn’t stop acid secretion stimulated by the parasympathetic nervous system. This is used as a preventative medication

Question 23

Describe the mechanism of action of proton pump inhibitors (PPIs) in reflux

Answer 23

Blocks the protein pump on the apical surface of parietal cells so prevent the production of acid entirely allowing the cells of the oesophagus to heal. They irreversibly bind to/block the H+/K+ ATPase or gastric proton pump on parietal cells

Question 24

What hormones do endocrine cells secrete?

Answer 24

Gastrin and histamine

Question 25

What is the role of gastrin and histamine in the stomach?

Answer 25

Stimulate acid production by binding to the basolateral surface of the parietal cells

Question 26

What activates the secretion of acid from the gastric parietal cells?

Answer 26

Histamine, gastrin and parasympathetic response to the sight of food (cephalic response)

Question 27

Describe how PPIs are administered to patients (inactive form)

Answer 27

Given in an inactive form which is lipophilic so it readily crosses cell membranes, and in an acidic environment the inactive drug becomes protonated and becomes active which then covalently, irreversibly binds to the gastric proton pump to deactivate it (prevent acid production)

Question 28

What are the disadvantages of PPIs?

Answer 28

HCl is involved in the digestion of proteins and absorption of nutrients, especially vitamin B12 and calcium, and therefore a deficiency of HCl can cause malnutrition

Question 29

Explain why antacids aren’t a long-term solution for acid reflux?

Answer 29

They only neutralise the stomach acid and don’t actually prevent the damage that the acid is doing to the oesophagus; doesn’t correct the relaxation of the LOS

Question 30

What are the potential consequences of having a helicobacter pylori infection of the stomach?

Answer 30

May cause GI conditions such as duodenal and gastric ulcers

Question 31

Describe blood antibody testing for helicobacter pylori

Answer 31

Checks to see if body has made H. Pylori antibodies, so if they are present, you are either currently infected or have been in the past

Question 32

Describe stool antigen testing for helicobacter pylori

Answer 32

Checks for H. Pylori antigens in the faeces

Question 33

What 3 methods may be used to diagnose oesophagitis?

Answer 33

Upper endoscopy, biopsy, upper GI series

Question 34

What are the symptoms of a helicobacter pylori infection?

Answer 34

Acute gastritis (stomach pain), nausea

Question 35

How can a helicobacter pylori infection lead to damage of the stomach?

Answer 35

Flagella grip to GI epithelia and protects them from gastric acid (are within mucosa), then bury in stomach mucosa and break down urea (produced by protein breakdown by pepsin) via urease enzyme –> ammonia and carbon dioxide. Ammonia produced is toxic to epithelia and begins breaking down stomach epithelia IN SOME INDIVIDUALS

Question 36

Does everyone with a helicobacter pylori infection experience symptoms?

Answer 36

No, up to 85% of those with infection have no symptoms or complications

Question 37

How is a H. pylori infection treated?

Answer 37

Antibiotics and PPIs to kill the bacteria

Question 38

Compare the epithelia at the gastro-oesophageal junction in a healthy individual

Answer 38

Oesophageal epithelia = stratified squamous

Gastric epithelia = simple columnar

Question 39

Compare the epithelia at the gastro-oesophageal junction in an individual with acid reflux

Answer 39

There may be some scarring/burns at the G-O junction

Question 40

Compare the epithelia at the gastro-oesophageal junction in an individual with Barrett’s oesophagus

Answer 40

There is simple columnar metaplasia in the oesophagus

Question 41

Name 4 anatomical features which prevent reflux

Answer 41

Contraction of crural diaphragm (pinch action at terminal oesophagus), viable LOS normally seals off stomach from oesophagus, enters cardia at an acute angle, terminal portion of the oesophagus is within the abdominal cavity

Question 42

Describe the histology of the gastro-oesophageal junction in someone with GORD

Answer 42

Oedema, leukocyte invasion, thinning of squamous layer, dysplasia, goblet cell intestinal metaplasia

Question 43

What substances are mainly secreted in the cardia of the stomach?

Answer 43

Mucus (mucous neck cells)

Question 44

What substances are mainly secreted in the fundus and body of the stomach?

Answer 44

Mucus (MNCs), HCl (parietal cells), pepsinogen (chief cells), histamine (endocrine cells)

Question 45

What substances are mainly secreted in the pylorus of the stomach?

Answer 45

Mucus (MNCs), histamine and gastrin (endocrine cells)

Question 46

What causes the pain of heartburn?

Answer 46

Heartburn pain occurs when afferent nerves in the oesophageal wall are activated by the presence of luminal acid; the acid moves through the epithelium of the oesophagus and activates receptors that generate a signal via spinal and vagal fibres to the central nervous system to cause the presentation of pain

Question 47

How is heartburn distinguished from oesophagitis?

Answer 47

Oesophagitis is inflammation of the oesophageal mucosa caused by frequent reflux of the stomach contents, whereas heartburn is merely the pain phenotype when there is acid reflux into the oesophagus

Question 48

How would oesophagitis be ruled out in a GORD diagnosis?

Answer 48

If there is no abnormality of the oesophagus in histology,, gross anatomy or upper GI series - if there was oesophagitis there would be constrictions and abnormalities of the oesophagus that are visible

Question 49

What can happen if too many antacids are taken?

Answer 49

Constipation/diarrhoea, renal problems and even chemical imbalance. In addition, as they bind acid, they can also work to bind medications as well, so they may have contraindications for use.