Pathology of Colon Flashcards
What is the small and large bowel peristalsis mediated by?
Intrinsically - Myenteric plexus
Extrinsic neural control - Autonomic innervation
Where is the Meissner’s plexus (Part of the myenteric plexus) found?
Base of the submucosa
Where is Auerbach’s plexus found?
Between the inner circular and out longitudinal layers of the muscularis propria
Is the duodenum intraperitoneal or retroperitoneal?
Retroperitoneal
Histologically, in the small intestine, what are the three cell types present and what are the three levels of the bowel wall?
Goblet, Columnar absorptive & Endocrine
Lamina propria, Muscularis mucosa & Submucosa
How long is the rectum and how much of it is extraperitoneal?
15cm
Distal 7cm
Histologically, what is the large bowel like?
No villi present
Flat with tubular crypts and the surface is made of columnar absorptive cells
What three types of cell may the crypts in the large bowel contain?
Goblet
Endocrine
Stem
What IBD of the lower GI Tract are there? (5)
UC CD Appendicitis Ischaemic colitis Radiation colitis
What drives the mucosal immune system to be activated?
The presence of normal intraluminal flora e.g. H. pylori
When diagnosing a patient what is it best to do?
Have a conversation - It could be? What it might be? No definitive answers
Where must UC originate from and where is it limited to?
Rectum
Colon
Where can UC never just present?
Caecum
What organ can be involved with UC and its systemic manifestations?
Appendix
In UC, what does the ulceration erode and what might the UC have?
Mucosa
Pseudopolyps
In UC, does the serosal surface have any inflammation?
Minimal or none at all
What kind of fibrosis occurs in UC?
Submucosal fibrosis
How is dysplasia categorised in UC?
High or Low grade
What complications of UC are there?
Haemorrhage
Perforation
Toxic dilatation
How does the mesentery thicken and fibrose in CD?
Granular serosa/dull grey wraps around the mesenteric fat
Histologically, how does CD appear? (4)
Cryptitis and crypt abscesses with atrophy leading to crypt destruction
Deep ulceration
Fibrosis is present
Contains non-caseating granulomas
What are the long term features of CD? (5)
Small Intestine has malabsorption Strictures Fistulas & Abscesses Perforation Increased risk of cancer
Where does Ischaemic Enteritis affect?
Small Intestine or Large Intestine or Both at the same time
What happens if one of the Coeliac, Inferior and Superior mesenteric arteries become occluded?
Infarction
Gradual occlusion will have little effect
What type of occlusion is less common?
Mesenteric venous
Histologically, how does acute ischaemia appear?
Oedema with interstitial haemorrhages
Initial absence of inflammation
Within 1-4 days bacteria gangrene and perforation has occured
Why is splenic flexure vulnerable?
It has an arterial sharp demarcation as the venous fades gradually
What is indicative of chronic ischaemia?
Mucosal inflammation Ulceration Submucosal inflammation Fibrosis Stricture
Radiation colitis - What does abdominal irradiation impair?
The normal proliferative activity of the small and large bowel’s epithelium
What are the symptoms of radiation colitis?
Anorexia
Abdominal cramps
Diarrhoea
Malabsorption
Histologically, how does radiation colitis appear?
Inflammation of crypt abscesses and eosinophils Necrosis Ulceration Haemorrhage Perforation
What is appendicitis?
Inflammation of the appendix causing tissue to regress with age and it has fibrous obliteration
Histologically, how does appendicitis appear?
Exudate
Perforation
Abscess
Acute gangrene leads to full thickness necrosis
In dysplasia, how does the adenoma present?
Tubular or Villous or Tubulovillous *90% of tubular occur in the colon*
What is the main type of tumour in colorectal carcinoma?
Adenocarcinoma (98%)
What are the risk factors for colorectal carcinoma?
Lifestyle
Family history
IBD
Genetics e.g. FAP & HNPCC
What are the two most common sites of metastases for colorectal carcinoma?
Liver
Lung
What are the signs of right sided (Ascending colon) adenocarcinoma?
Exophytic/polypoid Anaemia Vague pain Weakness Obstruction
What are the signs of left sided (Descending colon) adenocarcinoma?
Annular - Napkin ring lesion
Bleeding - Fresh/altered blood PR
Altered bowel habit
Obstruction
