ulcerative colitis

Question 1

define and epi

Answer 1

Ulcerative colitis (UC) is a form of inflammatory bowel disease. Inflammation always starts at rectum (hence it is the most common site for UC), never spreads beyond ileocaecal valve and is continuous.

The peak incidence of ulcerative colitis is in people aged 15-25 years and in those aged 55-65 years.

Question 2

pathology

Answer 2

Pathology

• red, raw mucosa, bleeds easily
• no inflammation beyond submucosa (unless fulminant disease)
• widespread ulceration with preservation of adjacent mucosa which has the appearance of polyps (‘pseudopolyps’)
• inflammatory cell infiltrate in lamina propria
• neutrophils migrate through the walls of glands to form crypt abscesses
• depletion of goblet cells and mucin from gland epithelium
• granulomas are infrequent

Question 3

s/s

Answer 3

The initial presentation is usually following insidious and intermittent symptoms. Features include:

• bloody diarrhoea
• urgency
• tenesmus
• abdominal pain, particularly in the left lower quadrant
• extra-intestinal features (see below)

Question 4

overlap between uc + cd

Answer 4

Question 5

how are flares of UC categorized

Answer 5

Mild

• Fewer than four stools daily, with or without blood
• No systemic disturbance
• Normal erythrocyte sedimentation rate and C-reactive protein values

Moderate

Four to six stools a day, with minimal systemic disturbance

• fever
• tachycardia
• abdominal tenderness, distension or reduced bowel sounds
• anaemia
• hypoalbuminaemia

Severe

• More than six stools a day, containing blood
• Evidence of systemic disturbance, e.g.
  
  • fever
  • tachycardia
  • abdominal tenderness, distension or reduced bowel sounds
  • anaemia
  • hypoalbuminaemia

Question 6

ix

Answer 6

• FBC - anaemia due to blood loss; leukocytosis
• ESR - increased; correlates with active disease
• CRP - raised; but less so than in Crohn’s disease
• biochemistry - in active disease, biochemical abnormalities may include hypokalaemia, hyponatraemia, hypomagnesaemia, hypocalcaemia, and hyoalbuminaemia. Abnormal LFTs due to associated chronic active hepatitis - increased ALT - or sclerosing cholangitis - increased alkaline phosphatase
• ANCA - found in HLA-DR2 associated form of ulcerative colitis
• radiology:
  
  • plain abdominal x-ray - excludes toxic dilatation, which is more than 5.5 cm in diameter in adults
  • barium enema:
    
    • diagnosis of extent and severity of the disease
    • procedure is contraindicated in those patients at risk of a toxic dilatation
• rectal biopsy - taken at sigmoidoscopy
• colonoscopy - this is contraindicated in those patients at risk of toxic dilatation. Allows multiple biopsies to be taken throughout the colon and delineation of the extent and activity of the disease
• white cell scan - allows imaging in severe disease
• molecular biology - a high intensity of CD44v6 and v3 epitope expression on crypt epithelial cells in patients with UC has been noted. This observation may have diagnostic potential in distinguishing UC from Crohn’s

Question 7

what features of uc are seen on barium enema

Answer 7

Barium enema

• loss of haustrations
• superficial ulceration, ‘pseudopolyps’
• long standing disease: colon is narrow and short -‘drainpipe colon’

Question 8

ddx

Answer 8

The differential diagnosis is influenced by the presentation, a principal factor being the age.

• Crohn’s disease
• infective colitis is often a cause of one episode of colitis which is mislabelled as ulcerative colitis e.g. salmonellosis, shigellosis, Campylobacter, amoebiasis. In the immunosuppressed patient then one must consider opportunistic infections e.g. cytomegalovirus, herpes virus, Cryptosporidium, Mycobacterium avium intracellulare.
• colonic carcinoma, adenoma - diagnosed on endoscopy, particularly important in the elderly
• diverticulitis - not in childhood
• irritable bowel disease, which would tend to occur in the young, and has early morning explosiveness, not tending to be bothered at night.
• ischaemic colitis - these patients may have a history of vascular disease with sudden onset of pain, and thumb printing on plain abdominal radiography or barium enema. It does not occur in childhood.
• post-radiation colitis, the diagnosis of which is based on the history

Question 9

mx

Answer 9

The severity of UC is usually classified as being mild, moderate or severe:

• mild: < 4 stools/day, only a small amount of blood
• moderate: 4-6 stools/day, varying amounts of blood, no systemic upset
• severe: >6 bloody stools per day + features of systemic upset (pyrexia, tachycardia, anaemia, raised inflammatory markers)

Inducing remission

• treatment depends on the extent and severity of disease
• rectal (topical) aminosalicylates or steroids: for distal colitis rectal mesalazine has been shown to be superior to rectal steroids and oral aminosalicylates
• oral aminosalicylates
• oral prednisolone is usually used second-line for patients who fail to respond to aminosalicylates. NICE recommend waiting around 4 weeks before deciding if first-line treatment has failed
• severe colitis should be treated in hospital. Intravenous steroids are usually given first-line

Maintaining remission

• oral aminosalicylates e.g. mesalazine
• azathioprine and mercaptopurine
• methotrexate is not recommended for the management of UC (in contrast to Crohn’s disease)
• there is some evidence that probiotics may prevent relapse in patients with mild to moderate disease

Question 10

local complications of uc

Answer 10

Local complications of ulcerative colitis include:

• haemorrhage
• malnutrition
• electrolyte imbalance
• toxic megacolon
• stricture formation - rare
• fistula formation - rare
• perforation
• increased risk of malignancy - lymphoma, carcinoma

Question 11

general complications of CD

Answer 11

• weight loss
• anaemia
• hypoproteinaemia
• arthropathy - tends to affect large weight-bearing joints
• liver associations:
• primary sclerosing cholangitis
• fatty liver
• non-specific hepatitis
• pericholangitis
• chronic active hepatitis
• bile duct carcinoma
• sacro-iliitis and ankylosing spondylitis
• pyoderma gangrenosum
• erythema nodosum
• anterior uveitis
• episcleritis
• carcinoma of the bile ducts - rare
• Note that gallstones are associated with Crohn’s disease but not ulcerative colitis.

Question 12

comparing CD + UC

Answer 12