pathology of the GI tract 1 Flashcards
What is gastro-oesophogeal reflux a precursor to?
barretts oesophagus
What is barretts oesophagus a precursor to?
oesophageal carcinoma
What epithelium is the normal oesophagus lined by?
layers of squamous epithelium
What is the oesophagus below the diaphragm lined by?
glandular (columnar) epithelium
What is oesophagitis?
Inflammation of the oesophagus
What are the two classifications of oesophagitis?
Acute and chronic
What causes oesophagitis?
infections (mainly in immunocompromised) e.g. viral (HSV1, CMV), fungal (candida), bacterial
chemical e.g. ingestion of corrosive substances, reflux of gastric content (most common cause)
What causes reflux oesophagitis?
reflux of gastric acid and/or bile
What are the risk factors for reflux oesophagitis?
defective lower oesophageal sphincter
hiatus hernia
increased intra abdominal pressure
increased gastric fluid vol due to gastric outflow stenoisis e.g. tumour
What is the leading clinical symptom for reflux oesophagitis?
heartburn - more burning that crushing pain unlike cardiac pain
What histological changes occur in reflux oesophagitis?
basal cell hyperplasia
elongation of papillae
scraping off of squamous cells
increase in number of inflammatory cells
What are the complications of reflux oesophagitis?
ulceration
haemorrhage (when ulcers goes into sub mucosa)
perforation
benign strictures (due to healing and contraction of scar tissue)
barretts oesophagus
What are the risk factors for barretts oesophagus and reflux oesophagitis?
male
caucasian
overweight
What is the histology of barretts oesophagus?
extension of sqaumo-columnar junction
squamous mucosa replaced by columnar mucosa = glandular metaplasia
What is important about the intestinal type of columnar mucosa in barretts oesophagus?
specialised barretts mucosa
contains goblet cells
used as diagnosis for barrets oesophagus
what are the two histological types of oesophageal carcinomas?
squamous cell carcinoma
adenocarcinoma
What group of people have higher incidence of adenocarcinomas?
male Caucasian smokers obese people who has barrets oesophagus
What does adenocarcinoma look like?
plaque like nodular fungating ulcerated depressed infiltrating
What are the risk factors for squamous cell carcinoma?
tobacco alcohol nutrition - source of nitrosamines thermal injury - hot beverages HPV male black ethinicity
What are the histological features of squamous dysplasia?
atypical, large nuclei
more mitosis that are atypical and typical which rise
basement membrane not breached = dysplasia
What staging is used for oesophageal carcinomas?
TNM
What are the causes of chronic gastritis?
Autoimmune Bacterial infection e.g. h. pylori Chemical injury NSAIDS Bile reflux alcohol?
What are the features of H. pylori and what does it do to the stomach?
damages epithelium therefore chronic inflammation of the mucosa most common in the antrum glandular atrophy replacement fibrosis intestinal metaplasia
What are the complications of H. pylori?
85% have no symptoms
gastric ulcers
duodenal ulcers
these predispose to gastric cancer
What is peptic ulcer disease?
ulcers in the stomach extending at leas into the submucosa
what are the major sites for peptic ulcers?
first part of duodenum
junction of antral and body mucosa
distil oesophagus
What are the major factors that cause peptic ulcers?
hyperacidity h. pylori duodeno-gastric reflux drugs (NSAIDs) smoking
what is the histology of a acute gastric ulcer?
full thickness coagulative necrosis of mucosa/deep layers
covered with ulcer slough (necrotic debris, fibrin, neutrophils)
granulation tissue on ulcer floor
flattening of the mucosa
what is the histology of chronic gastric ulcers?
clear cut edges overhanging the base
extensive granulation and scar tissue at ulcer floor
scarring through gastric wall
bleeding
What are the complications of peptic ulcers?
haemorrhage (could lead to anaemia)
perforation → peritonitis
penetration into adjacent organs
stricturing → hour glass deformity
What tends to cause gastric adenocarcinomas?
diet (smoked/cured meat, pickled veg) H. pylori bile reflux hypochlorhydria - allows bacterial growth hereditary
what is hypochlorhydria?
states where the production of hydrochloric acid in gastric secretions of the stomach and other digestive organs is absent or low
Who is most at risk of getting carcinoma of the gastric body/antrum?
those with h. pylori
those with a diet of high salt and low fruit and veg
What are the 6 macroscopic subtypes of gastric cancer?
superficial exophytic flat/depressed superficial excavated exophytic linitis plastica excavated
What are the 2 main histological subtypes of gastric cancer and describe them.
diffused type - scattered growth, poorly differentiated, ring cells, worse prognosis
intestinal type - tubular, glands, well differentiated, metaplasia
What is used to stage gastric cancer?
TNM staging
What is coeliac disease also known as?
coeliac sprue
gluten sensitive enteropathy
What is coeliac disease?
immune mediated enteropathy
caused by ingestion of gluten products as they contain GLIADIN - causes cells to express IL-15
IL-15 causes the activation/proliferation of CD8 and IELs
CD8 are cytotoxic and kill enterocytes
This causes atrophy of the villi
How does the diagnosis of coeliac disease come about?
commonly affects the ages of 30-60 years
Difficult to diagnose
can often be atypical presentation, silent disease, latent disease or symptomatic
What is the treatment for coeliac disease?
gluten free diet
How is coeliac disease diagnosed?
serologic tests e.g IgA/IgG
tissue biopsy
