Treatment of PU and IBD Flashcards
(29 cards)
What protective mechanisms are there
- Mucous secreting cells (trap bicarb ion, creates gel like barrier, important protective layer)
- Prostaglandins locally produced (stimulates secretion of mucous and bicarb, dilate mucous blood vessels)
What are the 3 secretagogues
- Gastrin
- ACh
- Histamine
Action of Ach
Stimulates muscarinic receptors on surface of parietal cells and histamine containing cells
Action of histamine
- Mast cells lying close to parietal cells release histamine
- Histamine release increased by gastrin and ACh
- Acts on parietal cell H2 receptors
What damage does H pylori do
Damage to protective layer
Associations of H pylori
- Causative factor in gastric and duodenal ulcer
- Risk factor for adenocarcinoma
- Strong link with MALT
- GI reflux disease
- Dyspepsia
- Iron deficiency anaemia
What occurs with acute H pylori infection
- Gastric mucosa inflamed with neutrophils and inflammatory cells
- Marked persistent lymphocytes penetration
What does outcome of chronic H pylori infection depend on
- Pattern of inflammation
- Host response
- Bacterial virulence
- Environmental factors
- Patient age
Diagnostic tests for H. pylori
- Non-invasive= urea breath test, stool antigen
- Biopsy based= CLO test (aka rapid urease test)
What does H pylori produce
Urease (Detected in urea breath test)
Treatment for H pylori
- PPI
- Amoxicillin
- Clarithromycin/metronidazole
Examples of PPIs
- Esomeprazole
- Lansoprazole
- Omeprazole
- Pantoprazole
- Rabeprazole
Indications for PPI used
- H pylori
- Peptic ulcer disease
- GORD
- Reflux oesophagitis
- Zollinger-Ellison syndrome
How do PPIs work
- Inhibits K+H+ATPase irreversibly
- Basal and simulated acid secretion reduced
- Drug is weak base and accumulates in acid environment of the canaliculi of stimulated parietal cell
Side effects of PPIs
- Headaches
- Confusion
- Impotence
- Rashes
Caution of PPIs
- Liver disease
- Pregnancy
- Breast feeding
- May mask symptoms of gastric cancer
Action of histamine H2 receptor antagonists
- Competitively inhibits histamine action at all H2 receptors
- Inhibits histamine, gastric and ACh stimulated acid production
- Pepsin secretion also falls with reduction in volume of gastric juices
When to use H2 receptor antagonists
- Peptic ulcers
- Reflux oesophagitis
Examples of H2 receptor antagonists
- Ranitidine (better tolerated)
- Cimetidine
Side effects of H2 receptor antagonists
- Diarrhoea
- Dizziness
- Muscle pains
- Transient rashes
- Alopecia
Cautions of H2 receptor antagonists
Can mask signs/symptoms of gastric cancer
Side effects of cimetidine
- Can interact with androgen receptors (gynaecomastia, decreased sexual function)
- Inhibits cytochome P450 (slows metabolism and potentiates action of a range of drugs like anticoagulants and tricyclics)
- Confusion in elderly
Define dyspepsia
Pain/discomfort in upper abdomen, exacerbated by food
Define GORD
- Acid reflux
- Associated with waterbrash
