Disorders of the oesophagus, stomach and small intestine Flashcards
What is GORD?
Symptomatic passage of gastric contents -> lowers oesophagus
What is the incidence of GORD?
1 in 10 Australians
What are the risk factors for GORD?
Decreased tone of lower oesophageal sphincter
Impaired mucosal defences
Increased intra-abdominal pressure
What causes decreased tone of the lower oesophageal sphincter?
Caffeine, fatty foods, hiatal hernia
What causes impaired mucosal defences?
Smoking, alcohol
What causes increased intra-abdominal pressure?
Pregnancy, obesity, ascites, lifting and bending
What is the pathophysiology of GORD?
Chronically low pH induces inflammation of lower oes. mucosa
What are the potential outcomes of GORD?
Healing with no residual effects
Healing with fibrosis (obstruction, dysphagia)
Blood loss -> iron deficiency anaemia
Oesophageal ulceration
Metaplasia = barrett’s mucosa
What is barrett’s mucosa?
Stratified squamous epithelium replaced by simple columnar epithelium
What is barrett’s mucosa considered to be?
A pre-malignant transformation (regular endoscopic review required)
What are the clinical features of GORD?
Heartburn: epigastric and/or retrosternal pain
- Agg factors: big meals, acidic foods, bending and lifting, lying supine
- Rel factors: Antacids
Dyspepsia
Dysphagia, odynophagia
What is the management of GORD?
Reduction of predisposing factors
Endoscopy to directly visualise mucosa and structural changes (e.g. hiatal hernia)
Biopsy for Barrett’s mucosa
What are the three medications for GORD?
Histamine H2-receptor antagonists
- Ranitidine, cimetidine
Proton Pump inhibitors
- Esomeprazole, pantoprazole
Antacids
- Mylanta, gaviscon, quick-eze
How do Histamine H2-receptor antagonists work?
Inhibits action of histamine at H2-receptors on gastric parietal cells
How do proton pump inhibitors work?
Inhibits H+/K+ ATPase pump
How do antacids work?
Neutralises HCl in oesophageal lumen
What is a peptic ulcer?
Ulceration in any part of the GIT exposed to gastric secertions
What is the incidence of peptic ulcers?
10-20% of Australians
Where are the most common sites for peptic ulcers?
Duodenal ulcers are more common than gastric- - 4:1
Duodenal ulcers: D1, gastric ulcers: lesser curvature
Usually solitary, coexist in 10% of cases
What is the appearance of peptic ulcers?
Circular punched-out lesion (1-3cm)
Ulcer extends into the muscularis and has a fibrous base
What is the bacteria that is linked to peptic ulcers?
H. pylori
90% of duodenal ulcers and 70% gastric ulcers
What are the pathogenic properties of H. pylori?
Produces urease - allows survival in low pH
Helical structure and flagella - burrowing capacity
Release of bacterial toxins and reactive oxygen species - direct damage to mucosa
Recruitment of neutrophils, mast cells and macrophages results in release of inflammatory cytokines (further injury)
What are other factors contributing to peptic ulcers?
NSAIDS
Smoking
Familial factors
How can NSAIDS cause peptic ulcers?
Reduce prostaglandin content of mucosal cells
Aspirin directly damage cell membranes
How can smoking cause peptic ulcers?
Generation of reactive oxygen species -> mucosal damage
Reduces the healing rate once an ulcer has formed
How can familial factors cause peptic ulcers?
Determine susceptibility to ulcers and site formation
Risk increases 3-fold if first degree relative has an ulcer
What are the clinical features of peptic ulcers?
Epigastric pain
- Periodicity of several weeks, disappears then returns
- Relationship to food: eating can either agg or relieve pain
Anorexia, dyspepsia, nausea, vomiting
Can be asymptomatic esp. in elderly
What are the complications of peptic ulcers?
Healing with fibrosis can cause pyloric stenosis (prevention of food into small intestine)
Blood vessel erosion can lead to:
- Iron deficiency, anaemia, melena and haematemesis
What is the management of peptic ulcers due to H. pylori?
Eradication with antibiotics, usually combined with proton pump inhibitor
What is the management of peptic ulcers without H. pylori?
Histamine H2 receptor antagonists or PPI used
What is the general management for all ulcers?
Cease smoking
Modify NSAID therapy
Regular endoscopic review
How do antibiotics work?
- Inhibition of cell wall synthesis
- Disruption of cell membrane
- Inhibition of protein synthesis
- Interference with metabolic processes