Treatment of peptic ulceration and Inflammatory Bowel disease Flashcards
What are gastric acid secretions required for?
- Digestion of food
- Iron absorption
- Killing pathogens
What are the protective mechansims against gastric acid?
Mucous secreting cells - Trap bicarbonate ions (alkaline) - Creates gel like barrier - Important protective layer Prostaglandins locally produced - Stimulates secretion of mucus and bicarbonate - Dilate mucosal blood vessels - Cytoprotective
How much gastric juice is produced per day?
2.5L
What are proenzymes e.g. prorennin and pepsinogen produced by?
Chief / peptic cells
What cells produce HCL and intrinsic factor
Oxyntic / parietal cells
What is intrinsic factor?
a substance secreted by the stomach which enables the body to absorb vitamin B12. It is a glycoprotein.
What does the production of HCl involve?
Proton pump (K+H+ATPase)
What does inhibition of the proton pump result in?
Less HCl being secreted by cheif cells therefore increased pH
What are the 3 endogenous secretagogues? (3 substances which increase HCl production)
- Gastrin
- Acetylcholine
- Histamine
What is gastrin produced by?
Gastrin cells (G cells)
What kind of substance is gastrin?
Polypeptide hormone
Where are gastrin cells located?
Gastric antrum and duodenum
What have a strong effect on the G cells?
Proteins in food
How does gastrin work?
- Secreted by G cells into blood
- Stimulates secretion of acid by parietal cells (thro the proton pump)
- Also increases pepsinogen secretion - stimulates blood flow and increases gastric motility
How does acetylcholine increase gastric acidity?
- Released from neurons to stimulate muscarinic receptors on surface of parietal cells and histamine containing cells
What does histamine act on to increase gastric acidity?
- Parietal cell H2 receptors
What cells release histamine?
- Mast cells lying close to parietal cell
What substances increase histamine release?
- Gastrin
- Acetylcholine
How does Helicobacter pylori damage the stomach?
- Damages mucosal barrier
- Creates inbalance between protective and destructive factors
What percentage of the population are infected in Helicobacter pylori?
Roughly 50% (30% in UK)
Where can peptic ulcers be found?
- Stomach or duodenum
- Gastric and duodenal ulcers = peptic ulcers
What can H pylori infection increase the chances of?
- Gastric cancer (adenocarcinoma)
- Strong link with MALT (Mucosa Associated Lymphoid Tissue) Lymphoma
- GORD, Dyspepsia, Atrophic gastritis, iron deficiency anaemia, idiopathic thrombocytopenic Purpura
What is dyspepsia?
Indegestion
What is the clinical name for bad breath?
Halitosis
What symptoms can an H pylori infection present with?
- Nausea
- Dyspepsia
- Malaise
- Halitosis
Acute infection lasts about 2 weeks
What happens to the mucosa as a result of H pylori infection?
- Gastric mucosa becomes inflammed with neutrophils and inflammatory cells with marked persistant lymphocyte penetration
What does the outcome of H pylori infection depend on?
- Pattern of inflammation
- Host response
- Bacterial virulence
- Enviromental factors
- Patient age
What does a h pylori chronic infection result in?
Local inflammation and gastritis
What are the tests used to diagnose H pylori infection?
- Urea breath test
- Stool antigen
- CLO test (rapid urease test)
What test would be used to diagnose H pylori infection in primary care?
- Urease breath test or stool antigen test as they are non-invasive
- Stool antigen test cannot be undertaken to check eradication