Pathology of the Small Bowel Flashcards
What can mesenteric artery atherosclerosis and thromboembolism from the heart (AF) cause?
Mesenteric arterial occlusion leading to small bowel ischaemia
What drugs can lead to non occlusive perfusion insufficiency?
Cocaine
What is the most metabolically active part of the bowel wall?
Mucosa, so most sensitive to hypoxia
In non occlusive ischaemia, what does much of the tissue damage occur after?
Reperfusion
What are gangrene, perforation, peritonitis, sepsis and death all complications of?
Ischaemia of the small bowel
What is a result of incomplete regression of vitello-intestinal duct?
Meckel’s Diverticulum
What is the rule of twos in Meckel’s Diverticulum?
2 inches long, 2 foot above ileocaecal valve in 2% of people
What kind of structure are Meckel’s Diverticulum?
Tubular
What might Meckel’s diverticulum contain?
Heterotopic gastric mucosa
What does Meckel’s diverticulum mimick, with bleeding, perforation, or diverticulitis?
Appendicitis
What three organs can give secondary tumours to the small bowel?
Ovary, colon, stomach
What are three primary tumours of the small bowel?
- Lymphomas
- Carcinoid tumours
- Carcinomas
What are lymphomas of the small bowel like in relation to type?
Non Hodkins
What are lymphomas of the small bowel derived from?
Maltomas (B-cell) derived
What does enteropathy associated T cell lymphomas (associated with coeliac disease), occur in?
Lymphomas of small bowel
Where is the commonest site for carcinoid tumours of small bowel?
Appendix
What are small, yellow, slow growing tumours?
Carcinoid tumours of small bowel
What can carcinoid tumours of small bowel cause?
Intussusception and obstruction
What happens when carcinoid tumour of small bowel metastases to the liver?
A carcinoid syndrome occurs producing flushing and diarrhoea
What two conditions is carcinoma of the small bowel associated with?
Crohn’s disease and coeliac disease
What happens to WWC in appendicitis?
Increases
What are 4 pathological features of acute appendicitis?
- Acute inflammation (neutrophils)
- Mucosal ulceration
- Serosal congestion, exudate
- Pus in lumen
What type of exudate is seen in acute appendicitis?
Yellow surface exudate
What is caused by an abnormal reaction to a constituent of wheat, flour, gluten which damages enterocytes and reduces absorptive capacity?
Coeliac disease
What condition has a strong associated with HLA-B8 and dermatitis herpetiformis?
Coeliac disease
What is the suspected component of gluten that is the toxic agent in coeliac disease?
Gliadin
What is coeliac disease mediated by?
T lymphocytes which exist within the small intestine epithelium
What is the normal lifespan of an enterocyte?
72 hours
In coeliac disease, what is there an increasing loss of enterocytes due to?
IEL mediated damage
What 4 things occur as a result of increasing loss of enterocytes due to IEL mediated damage?
- Loss of villous structure
- Loss of surface area
- Reduction in absorption
- Flat duodenal mucosa
What is coeliac morphology like?
Flat mucosal biopsy with total villous atrophy
In coeliac disease, where is the lesion worse?
Proximal bowel so duodenal biopsy is very sensitive
What 3 antibodies can be found in serology for coeliac disease?
- Anti-TTG
- Anti-endomesial
- Anti-gliadin
What happens to sugars, fats, amino acids, water and electrolytes in coeliac disease?
Malabsorption
What does malabsorption of fats lead to?
Steatorrhoea
What can reduced intestinal hormone production lead to? (Coeliac disease)
Reduced pancreatic secretion and bile flow leading to gallstones
