Upper GI Flashcards
What do chief cells secrete
Pepsinogen
What do parietal cells secrete
HCl and intrinsic factor
How is acid secretion from parietal cells controlled?
Nervous control- cephalic phase (thought, smell, taste of food)
Local control- gastric phase (distension of stomach)
Hormonal control- intestinal phase (food in duodenum-> somatostatin which inhibits acid production)
What stimulates secretion of H+ from parietal cells
Histamine, gastrin and acetylcholine
What does the parietal cell do to produce H+?
Proton pump -> exchanges H+ with K+ in gastric lumen
What is the parietal cell stimulated by?
Vagus nerve- acetylcholine (M3 receptor)
Gastrin (G receptor)
Histamine (H2 receptor)
Somatostatin -ve feedback doe to contents in duodenum
What is gastric cytoprotection?
Prevents digestion of stomach
Thin layer above mucosa surface
H+ taken away by sub-mucosal blood flow
Decreased blood flow = incr. H+ conc -> necrosis
What is somatostatin
Prostaglandin! incr. mucus, incr. bicarbonate, incr. blood flow, decr. acid.
Therefore NSAIDs may interfere with the negative feedback process
What is gastritis?
Inflammation of stomach lining
What may cause gastritis?
Inflammatory response of GI mucosa to H. Pylori -> leads to Gastric cancer
Why is H. Pylori bad?
Colonises beneath mucus layer-> ammonia production and inflammation -> decreases Somatostatin -> increases gastrin production -> increases acid production
(colonises -> inflammation -> decr. somatostatin - incr. gastrin -> incr. acid)
incr. acid = inflammation in duodenum = reduces local protection = Ulcers!
Damaged cells = less mucosa and less acid causing gastric ulcers and cancers
What is PUD?
Peptic Ulcer Disease
Gastric ulcers
What is a major cause of PUD
H. Pylori
NSAIDs
Smoking
What drugs may cause dyspepsia
NSAIDs
Sulfasalazine
Iron preps
Corticosteroids
Potassium
Bisphosphonates
Nitrates
Calcium antagonists
Theophylline
What are signs and symptoms of PUD
Gastric- Pain on eating (and epigastric pain)
Duodenal- localised pain between meals and at night, relief by eating
Summary- what causes gastric stomach ulcers
Prolonged exposure to H. Pylori
NSAIDs
Summary- what causes duodenal ulcers
Excessive acid secretion from stomach due to H. Pylori
What is GORD?
Upper GI condition
Symptomatic reflux caused by gastric juice
Can be from defective Lower oesophageal sphincter
What can lower the pressure of the lower oesophageal sphincter?
Diet- fat, chocolate, caffeine, alcohol
Smoking
High oestrogen
Drugs
What is a hiatus Hernia
Stomach pushed through diaphragm
Prevents LOS from closing and allowing stomach contents to escape
What drugs may cause a lower Lower oesophageal sphincter pressure?
Beta- 2 antagonists
CCBs
Diazepam
Alcohol
Oral contraceptives
Anticholinergics
What drug class usually causes oesophageal ulceration
Antibiotics!
How is GORD diagnosed?
Endoscopy
What is functional dyspepsia
AKA NonUlcerDisease
No obvious cause
How to treat functional dyspepsia
Eradicate H. Pylori if present
Neutralise acid etc
Monitor
How to manage stomach and duodenal ulcers?
Eradicate H. Pylori
Stop inappropriate therapy
Decrease acid to decrease gastritis and allow mucosa repair
-> Block H2 or proton pump
How to manage GORD?
Remove anything that decreases LOS pressure
Non pharmalogical advice
Rafting products- gaviscon
reduce acid production to enable recovery of oesophageal mucosa
What are some none pharmaceutical managements for GORD
Eat small meals
avoid fatty foods
Avoid eating within 4hrs of bed
Avoid tight clothing and lose weight
Raise head when eating
What are some managements for dyspepsia?
Neutralise acid
Reduce flatulence
Treatments OTC
What are antacids
neutralise acids
Eructation (burping)
Increases LOS pressure -> stimulates prostaglandin synthesis
Relief of heart burn and indigestion
Avoid long term - helps symptoms
eg: rennie
What are some side effects of Antacids
Al- constipation
Mg- diarrhoea
Avoid sodium when Pt has HT or cardiac problems
How do alginates work
forms a high pH viscid mass (raft) traps air and bubbles and CO2 from antacid with the stomach contents
Floats to top of stomach and protects oesophageal mucosa from stomach contents
How does dimethicone work
(simeticone)
Anti-foaming agent
Decrease surface tension of intragastric air bubble
Allows bubbles to escape - decrease bloating feeling
How do H2 receptor antagonists work
cimetidine etc
Compete for H2 receptor on parietal cells (if eat a big meal the overridden)
Helps PUD and mild oesophagitis GORD
What is the cause of the interactions with cimetidine
it binds to P450!
so interactions w phenytoin, theophylline, warfarin etc
name a H2 antagonist
Ranitidine
relieves heartburn, dyspepsia and hyperacidity
How long can H2 antagonists be used for OTC
6 days MAX
How do PPI (proton pump inhibitors) work
Omeprazole, lansoprazole etc
Blocks hydrogen- potassium ATPase enzymes
Prolonged suppression of acid secretion
Why PPI over H2 antagonists?
Heals ulcers more rapidly than H2 antagonists
Side effects of PPI’s?
Short term- nausea diarrhoea flatulence epigastric pain dry mouth headache
joint pain and muscle ache
When should someone take lansoprazole
Before food- food decreases bioavailability
What needs to be know about PPI use OTC -dose, duration, referral
dose - omeprazole 20mg a day until symptoms better then 10mg
Swallow whole w liquids
Refer if after 2 weeks, no relief
Refer if treatment req. for 4 weeks continuously
Refer if over 45yrs and present with new or changed symptoms
Other drugs that help upper GI issues
metoclopramide and domperidone
Sucralfate
Bismuth
Misoprostol
What treatments are used for functional and dyspepsia, gastritis or PUD?
remove causative agents
Dietary changes
Symptomatic agents
H2 antagonists or PPI’s
What treatments are used for GORD?
Lifestyle and dietary changes
use alginates or PPI’s
(NOT H2 ANTAGONISTS)
