Flashcards in Met: PBL 3 (GORD/Heartburn) Deck (49)
Form of indigestion pain felt as a burning sensation in the chest, caused by acid regurgitation into the oesophagus from the stomach
What is helicobacter pylori?
An organism found in the stomach and duodenum of many people with peptic ulcers,
What is a urea breath test used to diagnose?
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
What is gastroparesis?
Where the stomach takes longer than normal to dispose of stomach acid
How may being pregnant increase your risk of acid reflux?
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
Outline some of the risk factors for gastro-oesophageal reflux disease
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
Outline two medications which can lead to GORD symptoms
Calcium channel blockers (treat hypertension) and nitrates (treat angina) as these can relax the LOS
Outline four medications that can contribute to the development of oesophagitis
NSAIDs (includes ibuprofen), SSRIs (type of antidepressant), corticosteroids (treats severe inflammation), bisphosphonates (treat osteoporosis)
What is oesophagitis?
Where stomach acid irritates and inflames the lining of the oesophagus
What is the lower oesophageal sphincter (LOS)?
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
What is the cause of the symptoms associated with GORD?
The movement of acid back up into the oesophagus when the LOS has been weakened
Why is acid reflux proposed to be a vicious cycle?
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
Define 'acid reflux'
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
Name the treatments for GORD/acid reflux
antacids, H2 antagonists, PPIs
When may further investigations be required in someone who presents with symptoms of reflux?
If they have pain when they swallow, have difficulty swallowing OR when symptoms don't improve with medication
What is Barrett's oesophagus?
When the oesophageal epithelium undergoes metaplasia from stratified squamous to simple columnar and this increases the risk of oesophageal cancer largely
How can acid reflux lead to iron-deficiency or anaemia?
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
What is the mechanism of alginates in the treatment of GORD?
They form a 'raft' that floats on the surface of the stomach contents and reduces reflux and protects the oesophageal mucosa
What are potential treatment options for dysphagia?
Surgery to wide oesophagus, diet changed to more liquid food, fed by tube, speech therapy to develop different swallowing techniques
Describe the mechanism of action of antacids in the treatment of reflux
Contain alkaline ions (e.g. calcium/magnesium carbonate) which chemically neutralise the stomach acid contents
Describe the mechanism of action of H2 receptor antagonists in reflux
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
Describe the mechanism of action of proton pump inhibitors (PPIs) in reflux
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
What hormones do endocrine cells secrete?
Gastrin and histamine
What is the role of gastrin and histamine in the stomach?
Stimulate acid production by binding to the basolateral surface of the parietal cells
What activates the secretion of acid from the gastric parietal cells?
Histamine, gastrin and parasympathetic response to the sight of food (cephalic response)
Describe how PPIs are administered to patients (inactive form)
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)
What are the disadvantages of PPIs?
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
Explain why antacids aren't a long-term solution for acid reflux?
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