Pathology Flashcards
What are the two main causes of small bowel ischaemia?
- Mesenteric artery occulsion
- Non-occlusive perfusion insufficiency
Why may the mesenteric artery become occluded?
- Atherosclerosis
- Thromboembolism (from AF for example)
What are some causes for non-occlusive perfusion insufficiency of the small bowel?
- Shock
- Strangulation - obstructs venous return
- Drugs - cocaine
- Hyperviscosity
Which area of the small bowel is most affected by ischaemia?
Mucosa
(it is the most metabolically active tissue)
As time of ischaemia increases in the small bowel, what are the consequences?
Ischaemia worsens and deepens
Gangrene may eventually develop
What is the difference between the outcomes of:
a) Mucosal infarct
b) Mural infarct
c) Transmural infarct
a) Regeneration - mucosal integrity is restored
b) Repair and regeneration - a fibrous stricture forms
c) Gangrene - death occurs unless this part of the small bowel is resected
What is the danger of gangrene in the small bowel?
The small bowel will perforate, cause peritonitis, sepsis and even death
Which type of tumour, primary or secondary, are more common in the small bowel?
Secondary
(primary are very rare)
Which types of secondary tumours are common in the small bowel?
Metastases from:
- Ovaries
- Colon
- Stomach
Which types of primary tumours are likely to affect the small bowel?
- Lymphomas
- Carcinoid tumours
- Carcinomas
Which conditions are associated with carcinoma of the small bowel?
- Crohn’s disease
- Coeliac disease
Where will a carcinoma of the small bowel usually metastasise to?
- Lymph nodes
- Liver
What may be the clinical signs of appendicitis?
- Vomiting
- Abdominal pain
- RIF tenderness
- Increased WCC
What is the aetiology of appendicitis?
- Idiopathic
- Faecoliths
- Lymphoid hyperplasia
- Parasites
- Tumours
What are faecoliths?
Small hard lumps of faeces which can commonly enter and inflame the appendix leading to acute appendicitis
They are often the result of dehydration
What are the features of an appendix during acute appendicitis?
- Acute inflammation - involving the muscle coat
- Mucosal ulceration
- Serosal congestion
- Pus in the lumen
What happens to the muscular wall in appendicitis?
It thickens
What are the complications of appendicitis?
- Peritonitis
- Rupture
- Abscess
- Fistula
- Sepsis and liver abscess
Coeliac disease is due to an abnormal reaction to what?
Gliadin - a component of gluten
Coeliac disease is mediated by which cell type?
T-cells
(intraepithelial lymphocytes)
How is the mucosa in the small bowel affected during Coeliac disease?
The mucosal surface flattens and complete villus atrophy occurs
Which antibodies will be found in a sufferer of Coeliac disease?
- Anti-TTG
- Anti-endomesial
- Anti-gliadin
Why may coeliac disease often lead to anaemia?
There is poor absorption of iron, vitamin B12 and folate from the terminal ileum
Why are gallstones a potential complication of Coeliac disease?
There is reduced intestinal hormone production which reduces pancreatic secretion which in turn affects bile flow
