Ulcerative Colitis (UC)
·
= Chronic inflammation of colonic
mucosa (only). Unknown aetiology
·
More common than Crohn‟s.
·
1 in 1500 in US. Rare in developing countries
·
Peak incidence in 25 – 30 year
olds
·
Smoking is protective
·
Risk in 1st degree relatives increases
15-fold
·
F > M, W > B
·
Diarrhoea if disease extends
above rectosigmoid junction
·
Mucus and blood per rectum
·
Urgency to defaecate
·
Abdominal pain, tenderness
·
Relapsing-remitting in 65%
patients
·
If severe attack: fever, tachycardia,
hypoalbuminaemia
·
May have: erythema nodosum,
arthropathy, aphthous ulcers in mouth and liver complications
· Stool culture: exclude infectious
·
Bloods: ÂESR and
acute phase proteins
·
Possible deficiencies: Fe, Hb,
albumin, electrolyte abnormalities
·
Sigmoidoscopy: red, raw, granular
mucosa
·
Colonoscopy & biopsy. Spreads from rectum to some point in colon.
· Macroscopic appearance:
o Begins in rectum and extends in continuity to left colon. 40 – 50%
limited to rectosigmoid colon. 10% have pan-colitis, may also develop
„backwash‟ ileitis.
o Mild: Erythema only. Severe: Mucosal haemorrhages and broad-based
ulcerations (not deep though). Normal appearance during relapses
o Pseudopolyps: islands of remaining, regenerating mucosa
·
Microscopic appearance:
o Mucosal inflammation only: mucosal ulcers
o Neutrophils, plasma cells, histiocytes in lamina propria
o Crypt abscesses (neutrophils in crypt) suggestive of UC rather than
Crohn‟s. May extend into laminar propria to produce ulcers
o Chronically, mucosa becomes thin and atrophic
o Distortion of crypt architecture, branching
o Overtime ® dysplasia ® flat carcinomas (cf raised in colorectal cancer)
·
Microscopic (lymphocytic
colitis), Collangenous colitis or Crohn‟s colitis
·
Irradiation proctitis
·
Infection, IBS, or Cancer
·
CMV or herpes simplex in
immunosuppressed patients
· Anaemia due to chronic blood loss
·
Toxic megacolon: diameter of transverse
colon > 5.5 cm. Acute dilation of colon due to loss of muscle tone ® Âgas ®
distension ® vascular occlusion ® necrosis. May rupture ® peritonitis. Emergency
· ÂRisk of colon carcinoma. Key risk facts:
o How long have they had it (main one): 1% at 10 years, 30% at 30
years. Require regular screening
o How much bowel is affected: greatest in pancolitis. Minimal with only rectal involvement
o How well controlled is the inflammation
o Aggressive flat lesions, infiltrates quickly into lymphatics in
submucosa
·
Perforation
·
Fibromuscular strictures (check
to exclude malignancy)
·
Sulphasalazine +/- steroids (or
azathioprine). Need regular FBCs
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