13 Large Intestine/Inflammatory Bowel disease Flashcards
How does the colon (large intestine) differ from the small intestine?
How much fluid enters the colon per day and how much is excreted as faeces? (approximately)
1500ml enters colon
100ml leaves as faeces (diarrhoea is more then 100mls)
Where does the colonic mucosa get the majority of its nutrients from?
Fermentation of dietary fibre by microbiome: Short chain fatty acids derived
Which of the parts of the large intestine are secondarily retro peritoneal and which parts are intraperitoneal? (what does it mean to be secondarily retroperitoneal?)
Secondary retroperitoneal: structures originally lied intraperitoneally, but have been pushed aside and adhered to the body wall
Transverse colon and sigmoid colon= intraperitoneal
Sigmoid colon can twist- cut of own blood supply as has mesentary (volvulus)
Branches of superior mesenteric artery- Fill in the missing labels:
Describe the structure of the muscle in the large intestine (compared to the small intestine).
Longitudinal muscle= in 3 distinct bands- Teniae coli
Outline how water is absorbed in the colon:
- ENaC- induced by aldosterone
- most= in proximal colon*
- Tight junctions- less back diffusion of ions
Which organs of the gut are intraperitoneal and which are retroperitoneal?
Is the rectum retroperitoneal or intraperitoneal?
Branches of inferior mesenteric artery: Fill in the missing labels:
Explain how rectal varices can be caused by portal hypertension.
- Upper 1/3 of rectum drains into IMV (–> portal vein)
- Lower 2/3 drain into systemic venous system (bypass liver)
- Portosystemic anastamoses at rectum
- If blood can’t go through liver- backpressure- anastamoses= thin walled vessels and when dilated= varices
What is IBD? Give 2 common types of IBS?
What? Idiopathic inflammation of GI tract
2 common types?
- Crohn’s disease
- Ulcerative colitis
Differentiate between Crohn’s and Ulcerative colitis. (Where, pattern)
Give some symptoms for IBD:
May get some more systemic symptoms:
- MSK pain*
- Arthritis*
- Erythema nodosum, psoriasis*
- Primary sclerosing cholangitis*
- Eye problems*
What are the risk factors/associations for IBD? (3)
- Genetic
- Gut organism issue
- Immune response
- Possible triggers:
- antibiotics
- diet
- smoking
- infections
How might a patient with Crohn’s disease present?
- Loose stools (non-bloody)
- Weight loss
- Right lower quandrant pain (inflammation of terminal ileum) w./ tender mass
- Joint pain
- Mild perianal inflammation
- Low grade fever
- Mildly anaemic
What pathology might be found with Crohn’s disease? (eg on a colonoscopy)
- Skip lesions
- Hyperaemia- bowel= red and inflammed
- Cobblestone appearance
- Mucosal oedema
- Ulcers
- Transmural inflammation
- Fistulae- bowel/bladder/vagina/skin
What histological finding can be found in Crohn’s that can’t be found in ulcerative colitis?
How can Crohn’s be investigated?
- Bloods
- check for anaemia
- Colonoscopy
- skip lesions
- fistulae
- strictures
- cobblestone appearance
- CT/MRI
- bowel thickening?
- extramural problems
- obstruction
- Barium enma/follow through
- strictures/fistulae
How might a patient with ulcerative collitis present?
What is it called if a patient has a mix of ulcerative colitis and Crohn’s disease?
Indeterminate colitis
What histological changes might we see with ulcerative colitis?
Chronic inflammatory infiltrate of lamina propria
Crypt abscesses- neutrophilic exudate in crypts
Crypt distortion- dysplasia, darker/crowded nuclei
Reduced goblet cell number
What pathology might be found with Crohn’s disease? (eg on a colonoscopy)
What in investigations can be done into suspected ulcerative colitis? (similar to Crohn’s)
What can be seen on this barium follow through?
What is a double contract enema? What can be seen on this radiograph?
Double contrast enema= uses air and barium
Ulcerative colitis:
Lead pipe colon- lack haustral markings
Continuous lesions without skipping
Whole colon
Mucosal inflammation may cause granular appearance
Outline the treatment options for IBD:
What pathology might be found with Ulcerative colitis disease? (eg on a colonoscopy)
