Write about Crohn's Disease here.

• Chronic inflammatory GI disease characterised by Transmural Granulomatous Inflammation

• May affect any part of the gut, but favours terminal ileum and proximal colon

• Unaffected bowel between areas of active disease (skip lesions)

Cause:

• Unknown, though NOD2/CARD15 gene mutations increase risk

Prevalence:

• 100/100 000

Incidence:

• 5-10/100 000

• Bimodal peak - 15-30 and 60-80

• Smoking increases risk 3-4x

Symptoms:

• Diarrhoea

• Abdo pain

• Weight loss all common

• Fever, malaise and anorexia occur with active disease

Signs:

• Anaemia - GI tract blood loss

• Apthous ulceration

• Abdo tenderness

• RIF mass

• Perianal abscesses/fistulae/skin tags

• Anal/rectal strictures

• Extra GI Signs

• Clubbing

• erythema nodosum

• pyoderma gangrenosum

• conjunctivitis

• episcleritis

• iritis

• large joint arthritis

• sacroilitis

• ankylosing spondylitis

• fatty liver

• PSC

Rare:

• cholangiocarcinoma

• renal stones

• osteomalacia

• malnutrition

• amyloidosis