Colon + IBD

Question 1

What are the main functions of the colon ?

Answer 1

Removes water from indigestible gut contents
Produces vitamins (k)
Temporary storage until defaecation

Question 2

Does the large intestine have villi and crypts ?

Answer 2

No villi

Yes crypts

Question 3

How is the large intestine different from the small intestine in terms of wall ?

Answer 3

External longitudinal muscle incomplete : three bands : teniae coli

Question 4

What structures forms as a result of contraction of teniae coli ?

Answer 4

Haustra = sacculations

Question 5

How is water reabsorbed in the colon ? Which hormone acts on it ?

Answer 5

Facilitated by EnaC , sensitive to aldosterone
Sodium reabsorption drives water reabsorption
Tight junctions prevent water to go back to lumen

Question 6

What is the gastrocolic reflex ?

Answer 6

Rapid mass movement of gut content from distal colon to rectum when we eat

Gives urge to defecate

Question 7

What are IBS ? Give 2 eg

Answer 7

Group of conditions characterised by idiopathic inflammation of the GI tract

Crohn’s
Ulcerative colitis

Question 8

Which of the 2 common IBS can affect any part of the GI tract ?

Answer 8

Crohn’s

Question 9

What is the difference in lesions between Crohn’s and Ulcerative colitis ?

Answer 9

Crohn’s : transmural inflammation, deep linear ulcers, patches

UC: mucosal inflammation , continuous , begins from rectum , crypt abscess

Question 10

Which IBS disease involves the anus ?

Answer 10

Crohn’s

Question 11

What are the common extra intestinal problems seen in IBS ?

Answer 11

Arthritis 
Erythema nodosum (red nodules) 
Psoriasis
Liver and biliary tree pbm : primary sclerosing cholangitis 
Eye pbm : uveitis

Question 12

What causes IBS ?

Answer 12

Not known

Combination of genetic factors , altered gut organisms , immune response

Question 13

Which age groups are affected by Crohn’s and UC?

Answer 13

Crohn’s : 15-30 and over 60

UC: young adults

Question 14

How does Crohn’s usually present ?

Answer 14

Multiple non bloody loose stools a day 
Weight loss 
Right lower quadrant pain
15-30 yo 
Some joint pains 
Perianal inflammation 
Mild anaemia

Question 15

What are the macroscopic signs of Crohn’s ?

Answer 15

• Cobblestone appearance
• Skip lesions
• Thickened wall , narrow lumen
• Fistulae

Question 16

What is a risk factor for Crohn’s ?

Answer 16

Smoking

Question 17

What is the main microscopic sign of Crohn’s ?

Answer 17

Granuloma formation

Question 18

Which investigation are used for diagnosis of Crohn’s ?

Answer 18

Blood: anaemia
Colonoscopy
CT for bowel wall thickening, obstruction
Barium enema : strictures and fistula

Question 19

How does ulcerative colitis present ?

Answer 19

• Multiple bloody stools per day (or mucus)
• weight loss
• cramping , lower abdominal pain
• painful red eye :uveitis
• no temp, no anal involvement

Question 20

What are the macroscopic changes seen in UC ?

Answer 20

Continuous ulceration
Loss of haustra
Pseudopolyps
Friable mucosa

Question 21

What is the main microscopic change seen in UC ?

Answer 21

Crypt abscess: inflammatory cells infiltration

Question 22

What investigation are made to diagnose UC ?

Answer 22

Blood :anaemia
Stool cultures
Abdo X-ray

Question 23

What X-ray feature is specific to UC ?

Answer 23

Lead pipe colon

Question 24

Why is malnutrition seen in Crohn’s and not UC ?

Answer 24

Crohn’s can affect small intestine involved in nutrients absorption

Question 25

Which pharmacological treatment are indicated in IBS ?

Answer 25

- aminosalicylate : for flares - corticosteroids :flares - immunomodulators : fistulas

Question 26

Is surgery indicated for both IBS ?

Answer 26

Not for Crohn's : can affect any part of GI | Surgery is curative for UC , only if risk of toxic mega colon, precancerous change

Question 27

Give 3 eg of perianal manifestation of Crohn's

Answer 27

Skin tags Fissures Fistulae