Clostridium difficile infection

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Pathophysiology - The Gut Wrecker

  • Causative Agent: Gram-positive, spore-forming, obligate anaerobic rod.
  • Transmission: Fecal-oral route. Spores are highly resilient, resisting heat, acid, and alcohol-based sanitizers.
  • Mechanism of Injury:
    • Toxin A (Enterotoxin): Targets the brush border, causing inflammation, fluid secretion, and watery diarrhea.
    • Toxin B (Cytotoxin): More potent; causes actin depolymerization, leading to mucosal cell apoptosis and necrosis.

C. difficile colitis: pseudomembrane and inflammation

⭐ The toxins' destruction of the colonic epithelium leads to the formation of characteristic pseudomembranes-yellow-white plaques composed of fibrin, mucus, and inflammatory cells.

Risk & Presentation - Antibiotic's Revenge

  • Risk Factors:

    • Recent antibiotic use (📌 Clindamycin, Fluoroquinolones, Cephalosporins)
    • Advanced age (>65 years)
    • Recent hospitalization or long-term care residency
    • Proton Pump Inhibitor (PPI) use
  • Classic Presentation:

    • Profuse, watery, foul-smelling diarrhea (>3 loose stools in 24h)
    • Lower abdominal pain & cramping
    • Low-grade fever, leukocytosis
  • Severe Disease Hallmark:

    • Pseudomembranous colitis (yellowish-white plaques on colonoscopy)

Endoscopic view of pseudomembranous colitis

⭐ While Clindamycin is classically cited, third-generation cephalosporins are a very common cause of hospital-acquired C. difficile.

Diagnosis - The Toxin Trackdown

  • Best Initial Test: Stool testing. Options include:
    • Nucleic Acid Amplification Test (NAAT) for C. diff toxin genes.
    • Glutamate Dehydrogenase (GDH) antigen + toxin EIA combo.
  • Severity Markers: Suggest severe disease.
    • WBC > 15,000 cells/mL
    • Creatinine ≥ 1.5x baseline
  • Imaging: Abdominal X-ray or CT for complications like toxic megacolon (colonic diameter > 6 cm).

⭐ NAAT is highly sensitive but doesn't distinguish between active infection and colonization. A positive toxin EIA confirms active toxin production, indicating true disease.

Management - The Flora Force

  • Primary Goal: Discontinue the inciting antibiotic as soon as possible.
  • Prevention: Strict contact precautions (gown, gloves).

⭐ Alcohol-based hand sanitizers do NOT kill C. difficile spores; vigorous hand washing with soap and water is required to physically remove them.

High‑Yield Points - ⚡ Biggest Takeaways

  • C. difficile is a Gram-positive, spore-forming anaerobe transmitted via spores, often following antibiotic use.
  • Key risk factors include clindamycin, fluoroquinolones, cephalosporins, and proton pump inhibitors.
  • Pathogenesis is mediated by Toxin A (enterotoxin) and Toxin B (cytotoxin), causing diarrhea and colonic damage.
  • Clinical presentation ranges from mild diarrhea to life-threatening pseudomembranous colitis and toxic megacolon.
  • Diagnosis relies on stool NAAT/PCR for toxin genes.
  • First-line treatment is oral fidaxomicin or oral vancomycin.
  • High recurrence rates are managed with fidaxomicin or a vancomycin taper.

Practice Questions: Clostridium difficile infection

Test your understanding with these related questions

An 87-year-old male nursing home resident is currently undergoing antibiotic therapy for the treatment of a decubitus ulcer. One week into the treatment course, he experiences several episodes of watery diarrhea. Subsequent sigmoidoscopy demonstrates the presence of diffuse yellow plaques on the mucosa of the sigmoid colon. Which of the following is the best choice of treatment for this patient?

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Flashcards: Clostridium difficile infection

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Salmonella _____ causes inflammatory diarrhea

TAP TO REVEAL ANSWER

Salmonella _____ causes inflammatory diarrhea

enteritidis

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