What are the labs and treatment for a patient with a history of colitis who has recently experienced a recurrence of diarrhea?

Management of Recurrent Colitis with Diarrhea

For a patient with a history of colitis experiencing recurrent diarrhea, a stool culture, C. difficile testing, and CBC with inflammatory markers should be ordered immediately, followed by treatment based on the specific cause of colitis, with antibiotics for infectious causes or mesalamine/corticosteroids for inflammatory bowel disease.

Initial Laboratory Evaluation

Essential Tests

• Stool studies:

  • Stool culture for bacterial pathogens 1
  • Clostridioides difficile testing 1
  • Stool for ova and parasites (based on risk factors) 1
  • Fecal calprotectin or lactoferrin (to assess inflammation) 1, 2
  • Stool Hemoccult (occult blood) 1

• Blood tests:

  • Complete blood count with differential 1
  • C-reactive protein and/or erythrocyte sedimentation rate 1, 2
  • Serum electrolytes and albumin 1
  • Liver function tests 1

Determining Type of Colitis

Infectious Colitis

• Consider if:
  • Acute onset of symptoms
  • Recent antibiotic use (suspect C. difficile)
  • Fever
  • Recent travel
  • Food-borne outbreak exposure

Inflammatory Bowel Disease

• Consider if:
  • Previous diagnosis of ulcerative colitis or Crohn's disease
  • Chronic or recurrent symptoms
  • Blood in stool
  • Weight loss
  • Extra-intestinal manifestations

Microscopic Colitis

• Consider if:
  • Older patient
  • Chronic watery diarrhea without blood
  • Normal endoscopic appearance but histologic inflammation 3

Treatment Algorithm

If Infectious Colitis Suspected:

1. For C. difficile colitis:

   • If non-severe: Oral metronidazole 500 mg three times daily for 10 days 1
   • If severe: Oral vancomycin 125 mg four times daily for 10 days 1

2. For other bacterial pathogens:

   • Targeted antibiotics based on culture results
   • For empiric treatment of febrile dysenteric diarrhea: Consider azithromycin 4

If Inflammatory Bowel Disease Flare:

1. For mild to moderate ulcerative colitis:

   • Oral mesalamine 2.4-4.8 g daily 5
   • Consider topical mesalamine for distal disease 1

2. For moderate to severe disease:

   • Oral prednisolone 40 mg daily with gradual taper over 8 weeks 1
   • For severe disease requiring hospitalization: IV corticosteroids 1

Supportive Care (All Patients):

• Fluid and electrolyte replacement 2
• Avoid antiperistaltic agents until infectious causes ruled out 1
• Consider loperamide only after infection ruled out 2

Follow-up Recommendations

• Reassess in 3-6 weeks if treatment is successful 1
• If symptoms persist beyond 14 days without identified cause, consider non-infectious conditions 1
• Consider colonoscopy with biopsies if:
  • Patient is over 50 years old 1
  • Symptoms persist despite treatment 1
  • Alarm symptoms present (weight loss, blood in stool) 2

Common Pitfalls to Avoid

1. Failing to rule out C. difficile before starting immunosuppressive therapy 1
2. Using antidiarrheal agents in patients with severe colitis or suspected infectious colitis 1, 6
3. Not considering microscopic colitis in patients with normal endoscopic findings 3
4. Missing medication-induced diarrhea as a potential cause 2
5. Inadequate follow-up for patients with persistent symptoms 1

By following this systematic approach to diagnosis and treatment, the patient's recurrent colitis can be effectively managed to prevent complications and improve quality of life.