Ulcerative Colitis

 

• Background

  A type of inflammatory bowel disease.

  Pathophysiology

  • Continuous area of inflammation in rectum ± colon.
  • Inflammed, friable mucosa, with crypt changes, reduced goblet cells, and pseudopolyps. Submucosal inflammation and ulceration if severe.

  Epidemiology

  • Prevalence: 1/1000.
  • Bimodal onset: 15-25 years (commoner) and 55-65 years.

• Signs and symptoms

  Intestinal:

  • Diarrhoea: bloody in 75%. May contain mucus.
  • Lower abdo cramps.
  • Rectal symptoms: urgency, tenesmus.
  • Relative to Crohn's, it is more likely to present gradually.

  Attacks:

  • Tender distended abdo.
  • Fever
  • Anorexia and weight loss.
  • May be triggered by infection.

  Non-intestinal:

  • Eyes: uveitis, episcleritis, conjunctivitis.
  • Aphthous ulcers, though much less than in Crohn's.
  • Clubbing
  • Erythema nodosum, pyoderma gangrenosum.
  • MSK: entero-arthritis (usually large joints such as knee), ankylosing spondylitis.

  Hepatobiliary:

  • Primary sclerosing cholangitis.
  • Chronic hepatitis, NAFLD, and cirrhosis.

• Risk factors

  • Not-smoking i.e. it is less common in smokers.
  • Family history.
  • HLA-B27.

• Investigations

  Bloods:

  • ↑CRP/ESR in active disease. Other signs of inflammation e.g. ↑platelets, ↓albumin.
  • Hb and haematinics (iron studies, B12, folate): ⅓ patients have anaemia, usually anaemia of chronic disease or iron deficiency. Less commonly, ↓B12 or ↓folate anaemia.
  • U+E, Mg2+, and Ca2+ for nutritional deficiencies.
  • LFT for associated hepatobiliary disease.
  • Immunological: pANCA (70% in UC), ASCA (70% in Crohn's). Not routinely checked.

  Stool:

  • Culture to rule out infection.
  • Faecal calprotectin as a marker of inflammation, 93% sensitive and 96% specific for IBD.
  • C. diff toxin. Presence is a poor prognostic marker.

  Endoscopy with biopsy:

  • Sigmoidoscopy usually sufficient. Colonoscopy if poor response to treatment.
  • Endoscopy shows mucosal granularity, and biopsy shows crypt architecture changes, including cryptitis and crypt abscesses.

  Abdominal XR:

  • May show perforation or gross dilatation in a flare up or toxic megacolon (transverse colon dilation >6 cm).

• Management

  Medical

  In attack, assess severity with Truelove and Witts' criteria and induce remission:

  • Mild-moderate: 1st line is mesalazine PR if distal (descending colon, rectosigmoid) plus PO if proximal or refractory. 2nd line add prednisolone PO +/or PR. Usually managed as outpatient.
  • Severe: {≥6 stools/day, usually bloody} plus one of {fever, ↑HR, ↓Hb, or ESR >30}. Admit and give corticosteroids IV, then ciclosporin, biologic, or subtotal colectomy if refractory.

  Maintain remission:

  • Mesalazine PO +/or PR if rectosigmoid: 1st line after mild-moderate attack.
  • Azathioprine or mercaptopurine PO: 1st line after a severe attack, or if steroids needed twice in 1 year.

  Biologics and Janus kinase inhibitors:

  • Can be used for induction and maintenance in refractory moderate-severe disease.
  • Anti-TNFα: infliximab, adalimumab, golimumab.
  • Other agents: vedolizumab (anti α4β7-integrin), tofacitinib (anti JAK1 and JAK3).

  Surgical

  Needed in 30%.

  Indications:

  • Medically-refractory chronic or acute UC.
  • Toxic megacolon or perforation.
  • Dysplasia or malignancy.

  Elective:

  • Proctocolectomy with ileo-anal pouch anastomosis or end ileostomy.
  • Ileo-anal pouch avoids a stoma but is technically harder and carries higher morbidity in terms of functional and quality-of-life outcomes. The pouch is formed from several loops of ileum which are sutured side to side.
  • Ileo-anal pouch complications include pouchitis (50%), nocturnal seepage (15%), urgency (10%), and impaired fertility in women (due to adhesions). Pouchitis presents with loose and frequent stools; treat it with metronidazole PO.

  Acute:

  • Subtotal colectomy – sparing the rectum – with end ileostomy and long rectal stump. Ileorectal anastomosis is also possible.
  • Complications: sepsis, poor healing due to high dose steroids.

• Complications

  • Perforation
  • Toxic megacolon
  • Colorectal carcinoma. Screen with colonoscopy every 3 years, starting 10 years after onset, and consider removal if dysplasia found.
  • VTE