Pathology of the GI Tract Flashcards
What epithelium lines the oesophagus?
Squamous
What epithelium lines the oesophagus below the diaphragm?
Glandular (columnar) epithelium
What are the two oesophageal sphincters?
1) Cricopharyngeal
2) Gastro-oesophageal
Define: Oesophagitis
Acute/Chronic inflammation of the oesophagus
What type of Oesophagitis is the most common?
Reflux
What are the causes of Oesophagitis?
> Gastro-oesophageal reflux
> Duodeno-gastric (bile) reflux
What are the risk factors for Oesophagitis?
> Incr intra-abdominal pressure
Weak lower spincter
Hiatus hernia (stomach into thoracic cavity)
Gastric outflow stenosis –> increase fluid
What is the characteristic symptom of Reflux Oesophagitis?
Heartburn
What are the complications of Reflux Oesophagitis?
> Ulceration > Haemorrhage > Peforation > Barrett's Oesophagus > Benign stricture
What is a hiatus hernia?
When a part of the stomach abnormally protrudes through the diaphragm
What symptoms does a sliding hiatus hernia give?
Reflux symptoms
What symptoms does a para-oesophageal hernia give?
Strangulation
What occurs to the squamous epithelium in Reflux Oesophagitis?
> De-squamed
> Basal cell hyperplasia
What occurs to the lamine propria in Reflux Oesophagitis?
Infiltrated by inflammatory cells.
What is Barrett’s Oesophagus?
It is a premalignant condition assc with adenocarcinoma development.
What is the cause of Barrett’s Oesophagus?
Chronic Reflux
What are the risk factor’s for Barrett’s Oesophagus?
Male, Caucasian and overweight
What is macroscopically seen in Barrett’s Oesophagus?
An extension of the squamo-columnar junction
What is the histologically characteristic mark of Barrett’s Oesophagus?
Glandular metaplasia - Squamous to Columnar.
What is the process from Barrett’s Oesophagus to Adenocarcinoma?
Barrett’s Oesophagus –> Low grade dysplasia –> High grade dysplasia –> Adenocarcinoma
What two types of Oesophageal carcinoma are there?
> Squamous cell carcinoma
> Adenocarcinoma
Who is Adenocarcinoma higher in M or F? And by what ratio?
Males 7:1
In the oesophagus where are said carcinomas localised:
1) Squamous cell carcinoma
2) Adenocarcinoma
1) Upper and middle third
2) Lower
What are the risk factors for Squamous Carcinoma?
> Tobacco and alcohol
Nutrition (nitrosamines)
HPV
Hot thermal injury
What precedes Squamous Carcinoma?
Sqaumous dysplasia
What are each of the components of TNM tumour staging?
pT = Primary tumour invasion depth N = Regional lymph node M = Distant metastatis
What level does pT1 invade to?
Muscularis Mucosae or Submucosa
What level does pT2 invade to?
Muscularis Propria
What level does pT3 invade to?
Adventitia
To where does pT4 invade to?
Adjacent tissues
How many lymph nodes are invaded in pN2,3 and 4?
1) 1- 2
2) 3-6
3) 7+
What is the ABC of chronic gastritis aetiology?
Autoimmune, Bacterial, Chemical Injury
Explain the pathological mechanisms and histiological findings of Autoimmune chronic gastritis?
Pathological Mechanism:
> Anti-parietal
> Anti-intrinsic factor antibodies
> Sensitised T cells
Histiological Findings:
> Atrophied Gastric body
> Intestinal Metaplasia
Explain the pathological mechanisms and histological findings of Bacteria caused Chronic Gastritis?
Pathological Mechanisms: > Release cytokines > Liberate chemokines > Release mucolytic enzymes > Bacterial urease --> ammonia production > Immune response does tissue damage.
Histological findings:
> Active chronic inflammation
> Intestinal metaplasia
> Multifocal atrophy
Explain the pathological mechanisms and histological findings of chemical injury caused Chronic Gastritis?
Pathological mechanism:
Direct injury
Histological findings:
Foveolar hyperplasia
What type of bacterium is H.Pylori?
Gram negative spiral shaped
Where is H.Pylori mostly found?
Antrum > body
How does H.Pylori cause chronic inflammation?
Damaged epithelium lining.
What is a peptic ulcer?
A submucosal localised lesion
What are the major sites of a peptic ulcer?
> First part of the duodenum
Body-antrum mucosal junction
Gastro-oesophageal junction
What are the main causes of a peptic ulcer?
> Smoking > Drugs > Duodeno-gastric reflux > Hyperacidity > H.Pylori infection
What are the complications of a peptic ulcer?
> Perforation perionitis
Haemorrhage
Penetration into adjacent organs
Stricture into hourglass shape
What is the most frequent type of gastric cancer?
Adenocarcinoma
What is the incidence of gastric adenocarcinoma?
5th most common cancer but declining
What causes gastric adenocarcinoma?
> H.Pylori
Diet (smoked meats, pickled veg)
Bile refluex
Hypochlorhydria - 1% hereditary
What mutation can cause hereditary diffuse type gastric cancer?
Germline CDH1/E-cadherin mutation
What is Coeliac disease?
= Gluten sensitive enteropathy (small intestine disease)
What is the incidence of Coeliac disease?
0.5-1% general population
What is Gliadin, how does it work?
It is the part of gluten that can induce disease.
Induces epithelial cells to produce inter-leukin 15.
What is the pathogenesis mechanism of Coeliac Disease?
Gliadin stimulates epithelial cells –> release IL5.
IL5 activates CD8 and IEL –> They kill enterocytes
What diseases are associated with Coeliac?
> Dermatitis Herpatiformis - 10% of pt’s
> Lymphocytic colitis/gastritis
What cancers are assc with Coeliac?
> Enteropathy-associated T cell lymphoma.
> Small intestine adenocarcinoma
What tests are done for Coeliac disease?
> IgA against Tissue transglutaminase (TTG)
IgA/IgG against deaminated Gliadin
Anti-endomysial antibodies - v specific but less sensitive
