L20-21 Gastrointestinal Disorders Flashcards
What is a peptic ulcer?
A break in the mucus lining of the stomach or duodenum causes stomach acid to damage the epithelial lining
What are the main causes of peptic ulcers?
Helicobacter pylori infection (most common) and non-steroidal anti-inflammatory drugs (NSAIDS) or aspirin
How does Helicobacter pylori cause peptic ulcers?
Breaks down mucus layer and colonises stomach mucosa - allows acid to cause damage
How do NSAIDS (non-steroidal anti-inflammatory drugs) cause peptic ulcers?
They block cox-1, which is involved in prostaglandin and mucus production in stomach - cant form lining
What are the two main ways of diagnosing peptic ulcers?
Endoscopy or H. pylori testing
How can testing for H. pylori in relation to peptic ulcers be carried out?
(3)
Faecal antigen testing
Serum antibody quantitation
Carbon-13 urea breath test
What does the carbon-13 urea breath test test for?
How does this work?
H. pylori infection as a cause for peptic ulcers
Patient is given carbon-13 urea, H. pylori splits it into H2O and CO2, labeled CO2 in breath confirms infection
What is the recommended treatment for peptic ulcers?
Triple therapy regimen: - Proton pump inhibitor (reduces HCl production) - One pair of antibiotics - Amoxicillin and clarithromycin OR Metronidazole and clarithromycin
What is a gastrinoma?
A gastrin secreting tumour of the pancreas or duodenum that promotes gastric acid production
How is a gastrinoma diagnosed?
Fasting serum gastrin (FSG) levels - elevated
What is the treatment for a gastrinoma?
Surgery or proton-pump inhibitors
What is oral tolerance?
Suppression of immune response against antigens that have previously been eaten as they are seen as harmless
What role does the small intestine have in oral tolerance?
It must tolerate ingested food and microbiota, and recognise and control potential pathogens
What is Coeliac disease (CD)?
No oral tolerance to gluten
What is gluten?
Substance found in endosperm of wheat grains
What is the composition of gluten?
Composed of two proteins: gliadin and glutenin
What are the three major diseases caused by wheat?
Coeliac disease
Non-Coeliac gluten sensitivity
Wheat allergy
What is the difference between Coeliac disease and other conditions caused by wheat in terms of disease mechanism?
CD - autoimmune reaction causes oral intolerance of gluten
Others - hypersensitivity reaction mediated by IgE mechanism
Why is there an increased incidence of Coeliac disease (CD)?
4
Greater awareness, testing frequency, gluten exposure, and due to population’s underlying genetics
What are the four major symptoms of coeliac disease?
Malabsorption (weight loss)
Diarrhoea
Steatorrhea (fat secretion)
Abdominal distention
What is dermatitis herpetiformis?
What GI condition is this sometimes seen in?
Small groups of blisters on red plaques on knees, elbows, forearms and buttocks; can burst making them itch and sting
Coeliac disease
What biological sex has a higher risk of developing coeliac disease? How much higher?
Females (XX) - 1.5-2 times higher risk
What conditions can a first degree relative have that puts someone at higher risk of coeliac disease?
(4)
Autoimmune diseases (T1 diabetes, Hashimoto’s thyroiditis etc.)
Down’s syndrome
Turner’s syndrome
IgA deficiency
What has been identified in coeliac disease that makes it unique among autoimmune diseases?
(3)
Environmental trigger - gluten
Genetic contribution needed for disease to occur - HLA-DQ2 or HLA-DQ8 haplotype
Autoantibodies - against transglutaminase in 95% of patients
