Pathology of the Small Bowel Flashcards
What are the two different methods that can lead to Ischaemia of the small bowel?
- Mesenteric artery occlusion
- Mesentery artery atherosclerosis
- thromboembolism from the heart - Non occlusive perfusion insufficiency
- Shock
- Strangulation obstructing venous return
- drugs
- Hyper viscosity
Is bowel ischaemia usually acute or chronic?
Usually acute but can be chronic
What is the pathogenesis of small bowel ischaemia?
Mucosa is the most metabolically active part of the bowel wall.
Thus its the most susceptible to hypoxia.
Th longer the period of hypoxia the greater the extent of damage to mucosal wall and thus complications
As length of time of ischaemia increases, the layers of the bowel wall damaged are?
Mucosal–> Mural–> Transmural
Death of mucosal epithelium cells can be regenerated after a mucosal infarct. T/F?
True
The mural layer of the bowel wall can be completely regenerated. T/F?
Yes but a stricture (narrowing) remains.
What is the effect of transmural infarction on the body wall?
Gangrene formation
What are the best to worst pathological changes seen in bowel ischaemia?
- Resolution- ischaemic mucosal layer renewed.
- Fibrosis, stricture, mesenteric angina, obstruction.
- Gangrene, perforation, peritonitis, sepsis, ded
What is Meckel’s Diverticulum?
Congenital defect, marked by the presence of a slight bulge in the small intestine. Bulge is the remnants of the vitello-intestinal duct, of the human embryo
Meckel’s diverticulum is usually symptomatic?
False
What are the effects of Meckel’s diverticulum? (3)
- Bleeding
- Perforation
- Diverticulitis- mimics appendicitis
Primary tumours of the small bowel are common. T/F?
False, they are rare secondary tumours are much more common.
Which 3 types of cancer commonly metastasise to the small bowel?
- Ovary
- Colon
- Stomach
What are the 3 primary tumours found in small bowel?
- Lymphomas
- Carcinoid tumours
- Carcinoma
What are the types of Lymphomas?
All non Hodgkin types
- Can be Maltomas (B cell derived)
- Can be enteropathy T cell lymphomas- related to coeliac
Lymphomas- malignant of lymphocytes
Carcinoid tumours most commonly affect the _ .
Appendix
What are the effect of carcinoid tumours?
- Can cause intussusception (folding of one layer over another)
- Can cause obstruction
- If metastasis to liver- diarrhoea, flushing
What is the difference between a carcinoid and carcinoma?
Carcinoid- Neuro-endocrine tumour that is slow growing
Carcionma- Malignancy of epithelial cells of the skin or organ lining
Carcinoma is related to both Coeliac and Crohns disease? T/F?
True
Common areas of metastasis in carcinoma? (2)
- Liver
2. Lymph nodes
What is appendicitis? What group of people is it most common in?
Inflammation of the appendix.
Children
What are the common symptoms of appendicitis?
Vomiting, abdominal pain, RIF (right iliac fossa) tenderness.
Increased white cell count- finding not symptom
What is progression of the pathology of appendicitis?
- Acute inflammation (neutrophil)
- Mucosal ulceration
- Serosal congestion, exudate.
- Pus in lumen
Acute appendicitis must involve the _ coat, which _ .
Muscle, thickens
What are the complications that can occur in appendicitis?
Tip -everything to do with burst and leaking
- Peritonitis
- Rupture
- Abscess
- Fistula- abnormal pathway between two organs/vessels.
- Sepsis & liver abscess
What is Coeliac disease?
Abnormal reaction to wheat/gluten/barley that causes damage to the gut wall and thus malabsorption of food
Which component of gluten is meant to be the “toxic cell” in Coeliac?
Gliadin, which causes activation of IEL’s causing epithelial destruction
What are the effects of Coeliac on the bowel?
- Destruction of enterocytes (absorptive cells of the bowel)
- Loss of villous structure (atrophy)
- Reduced food absorption
- Flattened epithelial mucosa
The main food group that isn’t absorbed due to coeliac are proteins. T/F?
False- Fats
Fat malabsorption -steatorrhoea
Reduced hormone, pancreatic and bile secretion= gallstones
What are the clinical effects of Coeliac disease?
- Weight loss
- Anaemia
- Abdominal bloating
- Failure to thrive
- Vitamin deficiency
Others- T cell lymphomas, small bowel carcinoma, gall stones
