Small and Large Intestine Pathology Flashcards
What is a volvulus?
Complete twisting of a loop of bowel about its mesenteric base of attachment. Produces both lumenal and vascular compromise. Presentation includes features of obstruction and infarction.
What are the types of damage/involvement of ischaemic bowel?
i) Mucosal: no deeper than muscularis mucosa
ii) Mural: infarction of mucosa and submucosa
iii) Transmural: infarction of all three layers
Aetiology of ischaemic bowel by type/pattern?
Mucosal/mural: generally hypo perfusion
Transmural: generally acute vascular occlusion
What are the phases of intestinal response to ischaemia?
i) Hypoxic injury
ii) Reperfusion injury
Which intestinal segments are most susceptible to ischaemia?
Watershed areas at end of respective arterial supplies:
- Splenic flexure (SMA & IMA terminate)
- Sigmoid colon/rectum (less than SF; IMA/pudendal/iliac circulations end).
Macroscopic appearance ischaemic bowel.
- Mucosa haemorrhagic; may be ulcerated, dark red
- bowel wall oedematous and thickened (mucosa / all 3)
- intensely congested and dusky - purple red
Microscopic features of ischaemic bowel?
- atrophy and sloughing of surface epithelium
- crypts may be hyper proliferative
- inflammatory infiltrate initially absent; neutrophils recruited within hours of reperfusion
Microscopic features of chronic ischaemic bowel?
- fibrous scarring of lamina propria.
- atrophic surface epithelium
Complications of ischaemic bowel disease?
- bacteria translocation > sepsis
- perforation
Why is bowel surface epithelium prone to ischaemic injury?
Intestine capillaries run alongside glands from crypt to surface. Make hairpin turn at surface to empty into post-capillary venule. Protects epithelial stem cells in crypts from ischaemic injury but leaves surface vulnerable.
Hence morphologic signature of ischaemic bowel = epithelial atrophy with N - hyper proliferative crypts.
Histopathology of coeliac disease?
- Intraepithelial lymphocytosis
- Crypt hyperplasia
- Villous atrophy
Extra intestinal complaints of coeliac disease?
- Arthritis / joint pain
- Seizure disorders
- Apthous stomatitis
- Iron deficiency anaemia
- Puberty delay
- Short stature
Skin lesion associated with coeliac disease?
Itchy, blistering skin lesion = dermatitis herpetiformis present in 10%.
Serologic tests for coeliac disease?
- IgA tissue transglutaminase
- IgA or IgG deamidated gliadin
- Antiendomysial Abs (highly specific, less sensitive)
Complications of Coeliac disease?
Higher rate of malignancy esp
- enteropathy associated T cell lymphoma: aggressive lymphoma of intraepithelial T lymphocytes.
- small intestinal adenocarcinoma
