2. Clostridium Difficile Infection

 

 

1. Overview

  • Definition: CDI is characterized by diarrhea (≥3 loose stools in 24 hours) and either:
    • Positive C. difficile toxin test.
    • Clinical suspicion with pending toxin results.
  • Pathophysiology: Disruption of gut microbiota (e.g., from antibiotics) allows overgrowth of toxin-producing C. difficile.
  • Key Toxins:
    • Toxin A (enterotoxin).
    • Toxin B (cytotoxin).
  • Risk Factors: Recent antibiotics, PPI use, hospital stay, immunosuppression, advanced age.

2. Diagnostic Criteria

  • Diarrhea (≥3 Type 5-7 stools/day) AND one of the following:
    • Positive stool toxin or C. difficile PCR test.
    • Evidence of colitis (e.g., imaging or endoscopy).

3. Clinical Features

  • Diarrhea (foul-smelling, watery).
  • Fever, abdominal pain, nausea.
  • Severe cases: Toxic megacolon, hypotension, shock.

4. Markers of Severity

  • WCC >15 × 10⁹/L.
  • Temperature >38.5°C.
  • Creatinine >50% above baseline or rising acutely.
  • Imaging evidence of colitis.

5. Treatment Guidelines

General Principles:

  • Discontinue inciting antibiotics when possible.
  • Avoid antimotility agents.

Mild-to-Moderate CDI:

  • PO Metronidazole: 10-14 days.
    • If no response in 7 days, escalate to vancomycin.

Severe CDI:

  • First-Line: PO Vancomycin 125 mg QDS for 10-14 days.
  • Second-Line: PO Fidaxomicin (e.g., if continuing antibiotics).
  • Non-Responsive Cases:
    • High-dose PO Vancomycin (125-500 mg QDS) + IV Metronidazole.
    • Alternatively: Fidaxomicin.
  • Complicated CDI (e.g., megacolon, perforation):
    • Colectomy while lactate <5 mmol/L.

Recurrent CDI:

  • Recurrence occurs in ~20% after the first episode and up to 50-60% after the second episode.
  • Definition: Recurrence of diarrhea (≥3 loose stools) within ~30 days of resolution, with a positive toxin test.
  • Management:
    • Stop inciting antibiotics and PPIs.
    • Use Fidaxomicin or Vancomycin.
    • Multiple recurrences: Consider high-dose Fidaxomicin, pulsed/tapered Vancomycin, IVIG, or fecal microbiota transplant (FMT).

6. Special Considerations

  • Megacolon (Colon >10 cm): Emergency colectomy is indicated if there is no improvement.
  • FMT: Highly effective for recurrent CDI; restores gut microbiota.
  • Probiotics: Evidence is limited; not routinely recommended.