What is the best treatment option for a 24-year-old man with ulcerative colitis (UC) presenting with bloody diarrhea, left lower quadrant pain, and sigmoidoscopy findings of loss of normal vascular pattern with erosions up to the splenic flexure?

Treatment for Ulcerative Colitis with Left-Sided Disease Extending to the Splenic Flexure

The best treatment option for this 24-year-old man with left-sided ulcerative colitis extending to the splenic flexure is mesalamine oral and enema (option D).

Disease Assessment and Classification

This patient presents with:

• 2 months of bloody diarrhea (3-4 loose stools/day with blood and mucus)
• Left lower quadrant pain
• Sigmoidoscopy showing inflammation extending to the splenic flexure
• Laboratory findings showing anemia (Hb 10.9), elevated platelets (488), and elevated ESR (32)

Based on these findings, the patient has:

• Mild to moderate active left-sided ulcerative colitis extending to the splenic flexure
• No signs of severe disease (no fever, weight loss, or severe anemia)

Treatment Rationale

Why Combination Therapy is Superior

1. Disease Extent Considerations:

   • For left-sided colitis extending to the splenic flexure, combination therapy with oral and topical mesalamine is more effective than either treatment alone 1, 2
   • The AGA guidelines recommend combination oral and topical therapy for left-sided disease 1

2. Efficacy of Combination Therapy:

   • Topical mesalamine (enemas) delivers higher concentrations of medication directly to the inflamed mucosa 1
   • Oral mesalamine ensures treatment reaches the entire affected area, including the more proximal regions near the splenic flexure 1
   • The combination addresses both distal and proximal inflammation more effectively than single-route administration 2

3. Evidence for Enemas vs. Suppositories:

   • Mesalamine enemas can reach up to the splenic flexure, while suppositories only treat the rectum (10-15 cm) 1
   • For disease extending to the splenic flexure, enemas are more appropriate than suppositories due to the extent of distribution 1

Treatment Algorithm

1. Initial Treatment:

   • Oral mesalamine 2-4g daily (FDA-approved doses showing efficacy in clinical trials) 3, 4
   • Mesalamine enema 4g daily (typically administered at bedtime) 1

2. Expected Response:

   • Clinical improvement should be seen within days (reduction in bleeding by day 3) 5
   • Endoscopic remission rates of approximately 80% can be expected after 4 weeks with proper combination therapy 1, 5

3. Duration of Treatment:

   • Continue induction therapy for 4-8 weeks 1
   • After achieving remission, transition to maintenance therapy with oral mesalamine (minimum 2g/day) 1, 2

Why Other Options Are Inferior

• Option A (Mesalamine suppositories only): Insufficient for disease extending to the splenic flexure as suppositories only reach the rectum (10-15 cm) 1, 5

• Option B (Mesalamine oral and suppository): While this provides both systemic and topical therapy, suppositories cannot reach the entire affected area up to the splenic flexure 1

• Option C (Mesalamine enema only): Inadequate for complete treatment as it may not effectively treat the entire colon, particularly in patients with more extensive disease 1

Monitoring and Follow-up

• Assess clinical response within 2-4 weeks 2
• Monitor for common side effects of mesalamine (headache, nausea, abdominal pain)
• If inadequate response after 4-8 weeks, consider:
  • Increasing mesalamine dose
  • Adding corticosteroids (oral prednisolone 40mg daily) 1
  • Referral for consideration of immunomodulators if steroid-dependent 1, 2

Potential Pitfalls to Avoid

1. Underdosing: Using less than 2g/day of oral mesalamine is associated with higher relapse rates 1

2. Premature discontinuation: Continuing therapy even after symptom resolution is crucial for mucosal healing and maintaining remission 2

3. Poor adherence: Patient education about the importance of both oral and topical therapy is essential, as many patients prefer to avoid rectal therapy 1

4. Delayed escalation: Failure to escalate therapy promptly if no improvement is seen within 2-3 weeks 2

5. Overlooking renal function: Mesalamine can affect renal function and requires monitoring, especially in those with pre-existing renal impairment 3