GI Tract 1 (Upper GI) Flashcards
What type of epithelium lines most of the oesophagus?
Stratified squamous
What are the possible aetiologies of oesophagitis?
- Bacterial, viral (HSV1, CMV), fungal (candida)
- Ingestion of corrosive substances
- Reflux of gastric contents
What is the commonest cause of oesophagitis?
Reflux oesophagitis - caused by reflux of gastric acid (gastro-oesophageal reflux) and/or bile (duodeno-gastric reflux)
What are the risk factors for reflux oesophagitis?
- Defective lower oesophageal sphincter
- Hiatus hernia
- Increased intra-abdominal pressure
- Increased gastric fluid volume due to gastric outflow stenosis
What is an hiatus hernia?
- Abnormal bulging of a portion of the stomach through the diaphragm
- Sliding hiatus hernia = reflux symptoms
- Para-oesophageal hernia = strangulation
What histological changes are seen in reflux oesophagitis?
- Squamous epithelium
- Basal cell hyperplasia, elongation of papillae, increased cell desquamation
- Lamina propria
- Inflammatory cell infiltration (neutrophils, eosinophils, lymphocytes)
What are the possible complications of reflux oesophagitis?
- Ulceration
- Haemorrhage
- Perforation
- Benign stricture (segmental narrowing)
- Barrett’s oesophagus
What is the cause of Barett’s oesophagus?
Longstanding reflux
What are the risk factors for Barrett’s oesophagus?
Same as for reflux (male, Caucasian, overweight)
What are the macroscopic findings in Barrett’s oesophagus?
Proximal extension of the squamo-columnar junction
What are the histological features of Barrett’s oesophagus?
Squamous mucosa replaced by columnar mucosa > “glandular metaplasia”
What are the types of columnar mucosa found in Barrett’s oesophagus?
- Gastric cardia type
- Gastric body type
- Intestinal type = “specialised Barrett’s mucosa”
What is the relevance of Barrett’s oesophagus?
Premalignant condition with an increased risk of developing adenocarcinoma
What is the potential disease progression for Barrett’s oesophagus?
Barrett’s -> low-grade dysplasia -> high grade dysplasia -> adenocarcinoma
What are the 2 histological types of oesophageal cancer?
- Squamous cell carcinoma
- Adenocarcinoma
What are the risk factors for adenocarcinoma?
Male gender, tobacco, obesity, alcohol, Western populations
What are the macroscopic features of oesophageal adenocarcinoma?
Plaque-like, nodular, fungating, ulcerated, depressed, infiltrating
What are the risk factors for oesophageal squamous cell carcinoma?
- Tobacco and alcohol
- Nutrition (potential sources of nitrosamines)
- Thermal injury (hot beverages)
- HPV
- Male
- Ethnicity (black)
- More common in Eastern population
In what part of the the oesophagus are squamous cell carcinomas usually found?
Middle and lower third
In what part of the the oesophagus are adenomas usually found?
Distally
What are the features of Helicobacter pylori?
- Gram negative spiral shaped bacterium
- 2.5-5.0 micrometres long
- 4 to 6 flagellae
- Lives on the epithelial surface protected by the overlying mucus barrier
What is peptic ulcer disease?
Localised defect extending at least into submucosa
What are the major sites of peptic ulcer disease?
- First part of duodenum
- Junction of antral and body mucosa
- Distal oesophagus (GOJ)
What are the main aetiological factors in peptic ulcer disease?
- Hyperacidity
- H. pylori infection
- Duodeno-gastric reflux
- Drugs (NSAIDs)
- Smoking