Large Intestine/inflammatory Bowel Disease Flashcards
What part of the colon is retroperitoneal?
Ascending and descending colon
What part of the rectum is Intra peritoneal, Retroperitoneal and no peritoneum?
Upper 1/3 = Intra-peritoneal
Middle 1/3 = Retroperitoneal
Lower 1/3 = no peritoneum
What is the arterial supply to the midgut? (look at foregut DR slide)
Branch from SMA
Ileo-colic arerty = caecum
Right colic = ascending colon
Middle colic = transverse colon (2/3s)
What is the arterial supply to the hindgut? Look at foregut DR slide
Inferior mesenteric artery:
Left colic = descending colon
Sigmoid = descending colon
Superior rectal artery = upper 1/3 rectum
How does the longitudinal muscle surround the large intestine?
Incomplete longitudinal muscle layer leads to 3 distinct bands called teniae coli forming
What is the function of the teniae coli?
Maintaining the folds called Haustra in the large intestine
What ion channel facilitates water absorption in the colon?
ENaC
What hormone induces upregulatioon of ENaC?
Aldosterone
What is Inflammatory Bowel Disease?
Group of conditions characterised by idiopathic inflammation of the GI tract
What are the 2 most common types of Inflammatory bowel Disease?
Chrons disease
Ulcerative colitis
What ages are Chrons disease and ulcerative colitis most common in?
Young adults 20s
What is the key difference in location where Chron’s disease an Ulcerative colitis develop?
Chrons = anywhere in the GI tract but rarely ever the rectum
Ulcerative colitis = ALWAYS starts in RECTUM and stays contained in large intestine/colon
What is the most common spot of inflammation in Chrons disease?
Terminal ileum
What substances are mainly absorbed in they terminal ileum and therefore can be affected by Chron’s disease?
B12 absorption
Bile salts reabsorption
How does the pattern of inflammation differ in Chrons disease and ulcerative colitis?
Chrons = skip lesions (area of inflammation then normal, then inflammation)
Ulcerative colitis = continous pattern of inflammation
What part of inflammed area of gut is affected in Chron’s and ulcerative colitis?
Chron’s = transmural/full wall thickness
Ulcerative colitis = superficial/only the mucosal layer is inflammed
Despite Ulcerative colitis only being able to affect the colon/large intestine, what complication can occur affecting the terminal ileum with UC?
Backwash ileitis
What is backwash ileitis?
When patients with ulcerative colitis develop inflammation of terminal ileum due to the backwash of contents of the caecum into the terminal ileum
What are some extra intestinal problems that can occur with inflammatory bowel diseases?
MSK pain
Arthritis
Erythema nodosum (red nodules on kness)
Pyoderma gangrenosum (slide 12)
Cirrhosis of liver
Primary Sclerosing cholangitis
Uveitis (inflammation of middle eye)
What can trigger inflammatory bowel disease?
Genetics
Antibiotics
Infections
Smoking
Diet
What can trigger inflammatory bowel disease?
Antibiotics
Infections
Smoking
Diet
Which IBD does smoking increase the risk of?
Which IBD does smoking help dampen the symptoms of?
Smoking = inc risk of Chron’s
Smoking = reduced symptoms of ulcerative colitis
Why can Chron’s disease present with weight loss?
Why is the weight loss seen with Chron’s disease different to the weight loss seen with ulcerative colitis?
Nutrients are absorbed in the small intestine
Weight loss in Chrons s due to malabsorption of nutrients
Weight loss seen in Ulcerative colitis due to water loss
Why do patients with Chrons disease often have Right Lower Quadrant pain whereas ulcerative colitis is more broad?
In Chron’s, the terminal ileum is often the most commonly affected inflamed spot which is in the RLQ
What is a key symptom of Chrons that doesn’t normally occur in ulcerative colitis?
Perianal lesions in Chrons:
Skin tags
Fistulae
Abscesses
Scarring or sinuses
What is a fistula?
Abnormal connection between epithelial lined surfaces or organs
What is the term normally given to the abnormal connection between a structure and the skin?
Sinus
What is a skin tag?
Remnants of having a prolapsed haemorrhoid
What is a key difference in the stool contents of a patient with Chrons disease and ulcerative colitis?
Chrons = loose stool NO BLOOD
Ulcerative colitis = bloody stools (contain mucus)
What is a seton knot?
A knot that’s tied at a fistula which helps the fistula heal and drain any infection
What is the gross pathological appearance of Chron’s (what can be seen with an endoscope)?
Skip lesions
Hyperaemia (Red appearance)
Mucosal oedema
Superficial ulcers + deep ulcers
Transmural inflammation (full wall thickness) can narrow lumen
Cobblestone appearance
Fistulae
Describe the Cobblestone appearance seen in Chrons disease:
Cobbles = inflamed/oedmatous mucous
Grout/in between cobbles = ulcerations/bleeding
What is a key histological indications that an inflammtory bowel disease is Chrons disease and NOT UCLERATIVE COLITIS?
Epitheliod Granulomas
What is a granuloma?
Collection of epithelioid macrophages surrounded by lymphocytes
Look on slide 16 to see granuloma
How do you investigate Chrons disease?
Bloods to check for anemia to see for blood loss
CT/MRI (bowel wall thickening, obstruction and extramural problems)
Do barium enemas and follow through as contrast
Why can fistula, strictures an adhesions form in Chrons but not ulcerative colitis?
Chrons is transmural affecting the full thickness of the gut so needs to undergo repair which can go wrong
Whereas ulcerative colitis is superficial so doesn’t undergo repair
Go to the last slide, look at the CT on the left, what is the sign seen?
What is it indicative of?
Describe what causes this sign
Target sign
Chrons disease
Thickening and oedema of bowel wall due to chrons being transmural
The patient in the MRI on the right has chrons, what complication have they developed?
Where has it developed?
Stricture at hepatic flexure in transverse colon
What pathological changes can be seen in endoscopy of a patient with chrons?
Skip lesions
Cobblestone appearance
Fistulae
Strictures
What disease is indicated on the endoscope on the last slide?
Why?
Chrons disease
Cobblestone appearance
Are there Perianal diseases with Ulcerative colitis?
No
Why is blood loss per rectum very noticeable in Ulcerative colitis?
Since its always starts in the rectum
What are some different types of ulcerative colitis?
Proctitis
Proctosigmoiditis
Distal colitis
Extensive colitis
Pancolitis
What is proctiis?
Ulcerative colitis affecting just the rectum
What is pancolitis?
Ulcerative colitis affecting whole large intestine e
Why does ulcerative colitis present with mildly tender abdomen whereas Chrons is localised to the RLQ?
No focus point in UC
What pathological changes can be seen on a histology slide indicating ulcerative colitis?
Crypt abscesses
Crypt distortion
Reduced number of goblet cells
Chronic inflammatory infiltration of lamina propria
Go to the last slide:
What disease is the histology slide indicating?
Why?
Ulcerative colitis
Infilatrion of Lamina propria
Why is a reduction n goblet cells bad in UC?
Mucus acts as a protective barrier from microbes
What structure is absent in the large bowel but present in small intestine?
No villi
What are the folds called in the stomach?
Rugae
What are the permanent folds called in the small intestine called?
Plica circularis
What are the folds called in the large bowel?
Haustra
What changes can be seen in endoscopy with Ulcerative colitis?
Pseudopolyps
Loss of Haustra
What causes pseudopolyps in UC?
Inflammation then healing
What maintains Haustra in the large intestine?
The contraction of the 3 bands of muscle called the tiniae coli
Why are the haustra lost in Ulcerative colitis?
Inflammation leads to damage of the tiniae coli causing them to relax leading to loss of the haustra
How are the haustra distributed from the rectum through the large intestine?
Rectum smooth
As your progress through gets more and more haustra/folded
What are some investigations done for UC?
Bloods (anaemia)
Stool samples
Colonoscopy
If lesions are spotted on the mouth is it more likely Chrons or UC?
Chrons
Which IBD is fibrosis very common in?
Chrons
Which IBD are crypt abcesses common in?
Ulcerative colitis
Why can the bowel become obstructed in Chrons?
Deep inflammation leads to fibrosis which can produce strictures
Look at slide 35 to see skip lesions
Look at the last slide, CT labelled 2
What is this sign?
What is it indicative of?
Lead pipe colon
Descending and sigmoid colon featureless due to the haustra being absent since tiniae coli damaged by inflammation so are relaxed
What are the general medications given to treat IBD?
Aminosalicylates
Corticosteroids
Immunomodulators
When are steroids prescribed for IBDs?
With flare ups
How is Chrons cured?
Not curable
Structures and fistulas develop
If surgery remove as little bowel as possible
How is Ulcerative colitis cured?
Colectomy
But only done if inflammation doesn’t settle, getting pre cancerous changes or a toxic mega colon
What is a toxic mega colon?
Consequence of UC
Inflammation of colon so aggressive the colon distends
Due to loss of its tone it could burst
