IBD (inflammatory bowel disease)

Question 1

Definition

Answer 1

Group of disorders that cause chronic inflammation (pain and swelling) in the intestines.

Both types of IBD affect the digestive system.

Ulcerative colitis (affects only the large intestine)

Crohn’s disease (can affect the whole GI system)

Intermediate colitis (shows features of both UC and CD)

Question 2

General aetiology of IBD

Answer 2

Genetic susceptibility:
– familial aggregation of the disease
– genetic susceptibility stronger with UC than CD
– Increased incidence with HLA-B27 gene in IBD with ankylosing spondylitis

Environment:
– smoking associated with a 2x risk of Crohn’s disease
– stress and depression may cause relapses in IBD

Thought to be caused by an abnormal mucosal immune response to luminal bacteria in genetically predisposed individuals (genetic and environmental factors)

Question 3

Crohn’s disease

Answer 3

An idiopathic inflammatory bowel disease, characterised by multifocal areas of inflammatory which involve any part of the GI tract

Ileocolonic (40% of cases)

Small intestine (30-40% of cases)
– inflammation will be seen in skip lesions, within the small intestine

20% of cases in the large intestine have skip lesions
– known as Crohn’s colitis

10% of cases affect the perianal

Question 4

Chron’s disease aetiology

Answer 4

Thought to be caused by an abnormal mucosal immune reaction to luminal bacteria in genetically predisposed individuals

A true infectious aetiology is yet to be proven, but it is thought that mycobacterium plays a role

Question 5

CD epidemiology

Answer 5

Uncommon

Major incidence between 20 and 30

Question 6

CD risk factors

Answer 6

Smoking increases the risk 2x

Question 7

CD clinical presentation

Answer 7

Symptoms can depend on the region of the GI system involved

Major symptoms:
- diarrhoea
- abdominal pain
- weight loss

Ileocolonic:
– crampy RIF (mimicking appendicitis)
- diarrhoea occurs in 80% of colonic disease and usually contains blood

Small bowel disease:
– abdominal pain, usually with weight loss

perianal:
– anal fissures, tags and abscess formation

– diarrhoea which is usually not bloody
– fever
– malaise
– weight loss

Question 8

Ulcerative colitis

Answer 8

An idiopathic inflammatory bowel disease, characterised by inflammation restricted to the large bowel, which always involves the rectum and extends proximally in a continuous fashion for a variable distance

Result of a defective mucosal immune system producing an abnormal response to luminal antigens, such as bacteria which enter the intestine via a leaky epithelium

Question 9

UC Aetiology

Answer 9

Thought to be caused by an abnormal immune response to luminal antigens

Genetic link weaker than CD

Smoking appears to decrease the risk of ulcerative colitis

Question 10

UC epidemiology

Answer 10

Uncommon

Major incidence between the ages of 15 and 25

Question 11

UC Clinical presentation

Answer 11

Recurrent episodes of blood diarrhoea, often with urgency to go
- sometimes accompanied by lower abdominal discomfort

• lethargy, malaise and anorexia with weight loss

Tenasmus (feeling that you need to pass stools even though your bladders are empty)

Severe UC:
– diarrhoeas >6 per day
– fever
– tachycardia
– ESR rate >30mm/h
– Anaemia
– serum albumin <30g/l

Mild UC:
– diarrhoea <4 per day
– ESR rate <20mm/h
– serum albumin is normal

Question 12

Extra GI manifestations

Answer 12

All rare (occur in less than 10% of cases) other than:
– arthralgia
– fatty liver
– gallstones

Uncommon:
– eyes (conjunctivitis or uveitis)
– skin (erythema nodosum)
– joints (anky spond, small joint arthritis)