Inflammatory Bowel Disease

Question 1

What is the definition of Crohn’s disease?

Answer 1

Inflammatory disease affecting:

• the whole thickness of bowel wall
• in any part of the GIT (mouth to anus)

Characterised by:

• skip lesions
• granulomatous nature

Question 2

What are the peak age of incidence for Crohn’s?

Answer 2

20s

50 - 70

Question 3

What is the aetiology of IBD?

Answer 3

Immune reaction to commensal flora in genetically susceptible individuals triggered by some environmental factor

Question 4

What are the risk factors of Crohn’s disease?

Answer 4

Genetic - over 30 genes linked with Crohn’s

Diet

Smoking - increases flare up risk

Innate immunodeficiency

Certain microbes

Question 5

What is the pathophysiology for Crohn’s disease?

Answer 5

Abnormal immune response to gut flora

Mediated by T-helper-1 cells and macrophages

Leads to:
 - inflammation = infiltration of bowel wall by neutrophils
     [] granulomas found in ~50%
 - tissue damage
 - fibrosis

Question 6

What is the macroscopic appearance of Crohn’s?

Answer 6

Sharply defined skip lesions - may affect full thickness of bowel wall

• ulceration
• strictures, fissures, fistulae may develop

Affected sites

• mainly distal ileum
• but can affect anywhere in GIT

Question 7

What is the microscopic appearance of Crohn’s?

Answer 7

Infiltration of neutrophils

Crypt and villous damage

Granulomas

• aggregations of large macrophages
• non-casseated (cheese looking) as in TB granulomas

Metaplasia may occur

Question 8

What are the signs and symptoms of Crohn’s?

Answer 8

Presentation may be subtle in contrast to UC

Variation of symptoms according to site

GI symptoms:

• abdo pain
• bloating and flatus
• diarrhoea +/- blood
• intestinal stenosis/obstruction
• discomfort/ sores around anus +/- mouth

Systemic symptoms

• anorexia
• weight loss
• fever
• dietary deficiency => osteoporosis, anaemia (pernicious)

Other:

• uveitis
• rheumatological disease
• dermatological disease
• neurological symptoms

Question 9

What investigations should be done for Crohn’s disease?

Answer 9

Bloods

• FBC
• ESR and CRP
• Antibody serologies

X-ray: strictures/fistulae

• barium follow through
• barium enema

Colonoscopy +/- gastroscopy (can’t explore small bowel)
-> +/- biopsy = may aid diagnosis

Question 10

What are the complications of Crohn’s?

Answer 10

Obstruction

Fistulae

Abcesses

Short bowel syndrome (due to repeated resections)

GI cancer - increased risk due to metaplasia

Question 11

What is the prognosis of Crohn’s?

Answer 11

Chronic

No dramatic effect on mortality

Greater impact on QoL

Question 12

What is ulverative colitis?

Answer 12

Inflammatory disease affecting the mucosal layer of the colon and recum

Characterised by:

• Continous distribution
• Non-granulomatous nature

Secondary symptoms may affect other body parts

Question 13

Which gender is affected more and what is the peak age of onset?

Answer 13

Female > Male

Peak age: 20 - 25

Question 14

What are the risk factors for UC?

Answer 14

Genetic factors

Family Hx of autoimmune disease / porhphryias (enzyme disorder in heme pathway)

Diet

Question 15

What is the pathophysiology of UC?

Answer 15

Abnormal immune response to gut flora

Mediated by T-helper-2 cells and B cells which produce autoantibodies

Question 16

What is the macroscopic appearance of UC?

Answer 16

Inflammation of mucosal layer only

Starts in rectum and may affect any length of colon from rectum up, occasionally the distal ileum too

• 60% limited to rectum and sigmoid colon
• only 15% have pancolitis (total large bowel)

Continuous distribution with no skip lesions

Question 17

What is the microscopic appearance of UC?

Answer 17

Uniform, diffuse inflammation of the mucosa

• acute and chronic inflmmatory cell in lamina propria
• neutrophils in crypt epithelium and crypt lumen (acute cryptitis and crypt abcesses)
• distorted crypts and loss of mucin production
• congestion of blood vessels

Question 18

What are the signs and symptoms of UC?

Answer 18

GI symptoms

• diarrhoea: blood and mucous mixed with stool
• cramping of lower abdomen
• pain: left lower quadrant with distal disease extending to entire abdomen with pancolitis
• tenesmus: constant urge to defecate

Non GI symptoms:

• Fevers (40%)
• Weight loss (less than crohn’s though)
• Arthralgia/arthritis: peripheral large joints and axial

Question 19

What are the investigations of UC?

Answer 19

Stool examination: - microbiol - toxins

Bloods:

• FBC
• Inflammatory markers: CRP, ESR
• U&Es: hypokalaemia & hypomagnesaemia => diarrhoea
• LFTs: exclude primary sclerosing cholangitis (5%)

Abdominal X ray
- exclude toxic megacolon: determines disease extent

Endoscopy (colonoscopy) and biopsy

Question 20

How can UC be cured?

Answer 20

Total colectomy

Will leave patient with no colon though

Question 21

What are the complications of UC?

Answer 21

Primary sclerosing cholangitis (5%)

Bowel cancer

Toxic megacolon

Question 22

What is the prognosis of UC?

Answer 22

Most sufferers enter remission

• 20% without treatment
• severe sufferers less likely to sustain remission

~ 40% will require surgery within 20 years