Flashcards in Pathology of the stomach Deck (64)
List inflammatory disorders of the stomach
Rare causes of inflammation:
List some causes of acute gastritis
Irritant chemical injury
List causes of chronic gastritis
Which parts of the stomach is affected by autoimmune gastritis?
The fundus and the body (pangastritis)
What happens to the stomach in autoimmune gastritis?
There is atrophic gastritis and loss of parietal cells with achlorhydria (low or absent stomach acid production) and intrinsic factor deficiency.
There may be intestinal metaplasia.
What does the intrinsic factor deficiency cause?
A lack of vitamin B12 and pernicious anaemia
What antibodies are present in autoimmune gastritis?
Serum autoantibodies to gastric parietal cells and to intrinsic factor.
Those to parietal cells are common and nonspecific, whereas those to intrinsic factor are rare and more significant.
What is there an increased risk of in autoimmune gastritis?
Malignancy and SACDC (subacute combined degneration of spinal cord) due to B12 deficiency
What is a bacterial cause of chronic gastritis?
Helicobacter pylori - this is the most common cause of bacterial chronic gastritis
Where in the stomach does the H pylori inhabit?
In a niche between the epithelial cell surface and the mucous barrier
What does H pylori look like on gram stain?
Gram negative flagellate curvilinear rod
What is the response to H pylori in the stomach?
There is an early acute inflammatory response. If it is not cleared then a chronic active inflammation ensues.
Which inflammatory mediator is critical in the response to H pylori?
Where else other than the stomach is H pylori found?
In the duodenum in areas of gastric metaplasia.
Where is the prevalence of H pylori highest?
In developing countries (80-90%) and much lower in developed countries (20-50%)
How and when is H pylori infection usually acquired?
In childhood, either by the faecal-oral route or oral-oral route.
What is the most likely explanation for why the incidence of H pylori increases with age?
Probably due to acquisition in childhood when hygiene was poorer - the cohort effect- rather than infection in adult life.
Which enzyme does H. pylori produce?
How does H pylori damage the epithelial cells in the stomach?
Through the release of enzymes and inducing apoptosis by binding to the class II MHC molecules. The production of urease enabled the conversion of urea to ammonium and chloride, which are directly cytotoxic.
What are the possible results of H pylori infection?
Antral gastritis (the usual effect)
Peptic ulcers (duodenal and gastric)
What are the effects of antral gastritis?
It is usually asymptomatic, but can sometimes cause dyspepsia.
Chronic antral gastritis causes hypergastrinaemia due to gastrin release from G cells.
The subsequent increase in acid output is usually asymptomatic, but can lead to duodenal ulceration.
What do lamina propria plasma cells produce in response to H pylori infection?
anti H.pylori antibodies
What does H. pylori increase the risk of?
Duodenal and gastric ulcers
What can cause chemical gastritis?
NSAIDs, corticosteroids, alcohol and bile reflux
What happens to the mucous and epithelial layers in chemical gastritis?
There is direct injury to the mucous layer by fat solvents.
There is marked epithelial regeneration, hyperplasia, congestion and a little inflammation.
There may be erosion or ulcers.
Describe the general pathology in acute gastritis.
Surface epithelial degeneration
Regenerative hyperplasia of pit-lining epithelium
Neutrophil polymorph response
Describe the general pathology in chronic gastritis
Lymphocyte and plasma cell response
Lamina propria fibrosis
What is peptic ulceration?
A breach in the gastrointestinal mucosa as a result of acid and pepsin attack
What are the major sites of peptic ulcers?
The first part of the duodenum
The junction of the antral and body muscosa in the stomach
The distal oesophagus