What are the diagnostic steps and treatment options for ulcerative colitis?

Diagnostic Steps and Treatment Options for Ulcerative Colitis

The diagnosis of ulcerative colitis requires a combination of clinical, laboratory, endoscopic, and histopathological evaluations, with treatment options ranging from 5-aminosalicylates for mild disease to biologics and surgery for severe cases. 1, 2

Diagnostic Approach

Initial Evaluation

• Clinical presentation: Assess for chronic diarrhea, rectal bleeding, abdominal pain, and urgency
• Laboratory investigations:
  • Full blood count (anemia may indicate chronic blood loss)
  • Inflammatory markers (C-reactive protein, ESR)
  • Electrolytes, liver and renal function tests
  • Iron studies (ferritin <30 μg/L without inflammation or <100 μg/L with inflammation indicates iron deficiency)
  • Vitamin D level
  • Fecal calprotectin (accurate marker of colonic inflammation) 2
  • Stool testing for infectious pathogens including C. difficile 2

Endoscopic Evaluation

• Colonoscopy with biopsies is the reference standard for diagnosis 1
  • Obtain a minimum of two biopsies from at least five sites around the colon (including rectum) and ileum 1
  • Look for continuous inflammation beginning in rectum and extending proximally with decreasing severity 1
  • Assess for mucosal friability, erythema, loss of vascular pattern, and ulcerations

Histopathological Features

• Key diagnostic features:
  • Basal plasmacytosis (earliest diagnostic feature with highest predictive value) 1
  • Crypt architectural distortion and mucosal atrophy
  • Diffuse transmucosal inflammatory infiltrate
  • Active inflammation with cryptitis and crypt abscesses 1

Disease Classification

• Extent of disease (Montreal Classification):
  • E1: Proctitis (limited to rectum)
  • E2: Left-sided colitis (up to splenic flexure)
  • E3: Extensive colitis (beyond splenic flexure)
• Disease severity (Mayo Score):
  • Stool frequency
  • Rectal bleeding
  • Mucosal appearance
  • Physician's global assessment 1

Treatment Algorithm

Mild to Moderate Disease

1. First-line therapy: 5-aminosalicylates (5-ASA)

   • For proctitis: Topical 5-ASA (suppositories or enemas)
   • For left-sided or extensive colitis: Oral 5-ASA with or without topical therapy 3

2. If inadequate response: Add oral corticosteroids (short-term use only due to side effects) 3

Moderate to Severe Disease

1. Induction therapy: Oral corticosteroids

   • For hospitalized patients with severe disease: Intravenous corticosteroids 4

2. Maintenance therapy (steroid-sparing):

   • Immunomodulators (azathioprine)
   • Biologics:
     • TNF inhibitors (infliximab 5 mg/kg at 0,2, and 6 weeks, then every 8 weeks) 5
     • Anti-integrin agents (vedolizumab)
     • Anti-IL-12/23 (ustekinumab)
   • JAK inhibitors (tofacitinib)
   • Sphingosine-1-phosphate modulators (ozanimod) 6

Severe Acute Colitis Requiring Hospitalization

• Immediate assessment:

  • Full blood count, CRP/ESR, electrolytes, liver function
  • Stool for infectious pathogens including C. difficile
  • Plain abdominal radiograph (assess for toxic megacolon) 1
  • Limited flexible sigmoidoscopy (avoid full colonoscopy) 1

• Treatment:

  • Intravenous corticosteroids
  • If no response within 3-5 days: Consider rescue therapy with infliximab or cyclosporine
  • Surgical consultation for potential colectomy 4

Disease Monitoring

• Regular assessment of:
  • Clinical symptoms
  • Laboratory markers (CBC, CRP)
  • Fecal calprotectin (correlates with endoscopic inflammation) 1
• Endoscopic evaluation to assess mucosal healing 3-6 months after treatment initiation 1
• Surveillance colonoscopy beginning 8 years after disease onset for extensive colitis and 12-15 years for left-sided disease, then every 2-3 years 4

Important Considerations

• Extraintestinal manifestations occur in up to 25% of patients (joints, skin, eyes, liver) 4
• Cancer risk increases with disease duration (4.5% after 20 years) 6
• Microbial testing should be performed with every disease flare 2
• CMV testing is recommended in treatment-refractory cases 2

Treatment Pitfalls to Avoid

• Prolonged corticosteroid use (aim for steroid-free remission)
• Failure to assess for mucosal healing (clinical symptoms alone are insufficient)
• Inadequate cancer surveillance in long-standing disease
• Overlooking infectious complications (especially C. difficile)
• Delaying surgical consultation in severe refractory disease

Remember that the goal of treatment is not just symptom control but endoscopically confirmed mucosal healing, which is associated with better long-term outcomes including reduced risk of colectomy 3.