Inflammatory bowel disease (colon pathology) Flashcards
What are the sections of the large bowel and how are they peritonised?
Caecum (retroperitoneal)
Ascending colon (Retroperitoneal)
Transverse colon (Intraperitoneal)
Descending colon (Retroperitoneal)
Sigmoid colon (Intraperitoneal)
Rectum (retroperitoneal)
What 3 cell types are most present in the small bowel?
Goblet cells
Columnar absorptive cells
Endocrine cells
What types of cells are found in crypts in the small intestine?
Stem cells Goblet cells Endocrine cells Paneth cells
How long does the process of cell renewal take in the small intestine?
4-6 days
How is the basic mucosal structure of the large bowel different to the small bowel?
Flat with no villi Tubular crypts On the surface, there is only columnar absorptive cells In the crypts, there are goblet cells, endocrine cells and stem cells (no cells of Paneth)
Neuromuscular control of the small/large bowel involves both intrinsic and extrinsic control What are these control mechanisms?
Intrinsic control is via the myenteric plexus Extrinsic control is through autonomic innervation
What are the 2 parts of the myenteric plexus?
Meissener’s plexus - around the base of the submucosa
Auerbach plexus - between the inner circular and outer longitudinal layers of the muscularis propria
What is idiopathic inflammatory bowel disease?
Chronic inflammatory conditions arising from inappropriate and persistent activation of the mucosal immune system - driven by the presence of normal intraluminal flora
What are the 2 types of idiopathic inflammatory bowel diseases?
Ulcerative colitis
Crohn’s
Crohn’s disease and Ulcerative colitis are in many ways similar, but have a couple of key differences What is the difference between where they can be located?
Crohn’s can affect anywhere from the mouth to anus. Ulcerative colitis is limited only to the colon
Is family history important in Crohn’s patients?
Yes 15% have affected 1st degree relatives
Lifetime risk if either a parent or sibling is affected is 9%
What gene mutation is associated with Crohn’s disease?
NOD2
What gene mutations are associated with Ulcerative colitis?
HLA genes
What overall is believed to cause Crohn’s and Ulcerative colitis?
Strong immune response against normal flora with defects in the epithelial barrier function in genetically susceptible individuals
What is the role of intestinal flora in development of Crohn’s and UC?
No specific microbe has been identified
Defects in mucosal barrier could allow microbes access to mucosal lymphoid tissue triggering immune response
How are Inflammatory bowel diseases diagnosed?
Clinical history
Radiographic examination
Pathological correlation
What is pANCA, and why is useful in the diagnosis in some IBDs?
Perinuclear antineutrophilic cytoplasmic antibody (pANCA)
positive in 75% of UC patients BUT only 11% of CD patients (so not that useful for Crohn’s)
Describe the epidemiology of Ulcerative colitis
Male = Female frequency
More common in 20-30 and in 70-80 year olds
What are the types (by area) of ulcerative colitis?
Large bowel:
![](https://s3.amazonaws.com/brainscape-prod/system/cm/288/396/904/a_image_thumb.jpeg?1569586646)
What is backwash ileitis?
Inflammation in the distal ileum thought to be due to “backwash” of cecal contents
(patients with pancolitis may develop this)
What is the prevalence of ‘Pancolitis’?
10% of UC patients
What other small part of the alimentary canal can be involved in UC?
Appendix