Makindo Medical Notes

Diagnosis requires demonstration of the Clostridioides difficile toxin. The presence of Clostridioides difficile itself is not sufficient

Isolation if an infective cause suspected. Gown up and wear gloves, which should be placed in the bin in the patient's room. Ensure hands washed with soap and water to remove any C. difficile spores.

About

• Clostridioides difficile is an anaerobic spore forming bacterium
• Now called Clostridioides difficile
• It is found in intestines.
• It can be found in healthy people, where it causes no symptoms

Characteristics

• Large gram-positive anaerobic terminal spore-forming rods
• Irregularly shaped colonies on blood agar

Source

• Found in the soil or in the bowel or in the environment as spores
• Cultured from stool of 3% of population
• Found in 30% of hospital patients and 66% of babies
• Pathogenicity when antibiotics kill off other gut bacteria
• This allows C. difficile to grow to unusually high levels.
• It also allows the toxin that some strains of C. difficile produce to reach levels where it attacks the intestines and causes mild to severe diarrhoea.
• It can lead to more serious infections of the intestines with severe inflammation of the bowel (pseudomembranous colitis).

Risks

• Antibiotics, particularly the elderly
• Those whose immune systems are compromised.

Aetiology

• Toxin A - an enterotoxin and cytotoxic acts on gut mucosa
• Toxin B - a cytotoxin that cause the death of colonic luminal cells
• Third substance that inhibits bowel motility
• Together these cause ulceration and diarrhoea
• Ribotype 027 is associated with a very virulent form of infection with higher toxin production and quinolone resistance

Antibiotics associated

• The use of broad-spectrum antibiotics is associated with PMC especially
• Ampicillin, Amoxicillin, 2nd/3rd generation Cephalosporin
• Clindamycin and quinolones

Pathology

• Colonic inflammation and mucosal damage
• Inflammatory exudate forms pseudomembranes
• Due to infection with Clostridioides difficile (CD)

Clinical

• Diarrhoea may begin within 4-10 days of antibiotic treatment but may be delayed up to 6 weeks
• Asymptomatic to mild diarrhoea to pseudomembranous colitis
• Copious liquid stool with Fever, malaise
• Abdominal pain and distension and toxic megacolon, perforation and death

Investigations

• FBC, U&E, LFT, AXR may suggest dehydration/prerenal failure
• CT Abdomen if needed
• C. difficile toxins A and B.
• Colonoscopy/Sigmoidoscopy may show yellow adherent plaques
• Anaerobic culture on cycloserine, cefoxitin and fructose (CCFA) media
• Stools - the presence of CD toxin A and B which may need repeated
• Stool culture to exclude other infective causes
• AXR/CXR exclude perforation, ileus, megacolon

Differentials

• Diarrhoea due to NG and PEG feeds
• Salmonella, Shigella, Campylobacter, E Coli 0157
• Viral Gastroenteritis

Complications

• Prerenal failure
• Toxic megacolon and Colonic perforation

Severity Assessment

• Mild
  • WCC < 15 x 10⁹/l
  • < 5 stools per day of type 5-7 on Bristol stool chart
• Severe: any of these should suggest using oral vancomycin (or fidaxomicin) in preference to Metronidazole
  • WCC >15x 10⁹/l
  • an acute rising serum creatinine (i.e. >50% increase above baseline)
  • a temperature of >38.5 C
  • evidence of severe colitis (abdominal or radiological signs)
  • The number of stools is a less reliable indicator of severity.
• Life threatening CDI
  • Hypotension
  • Partial or complete ileus
  • Toxic megacolon or CT evidence severe disease

Other markers of poor prognosis

• CDI due to ribotype 027 strains is associated with increased severity
• Elevated blood lactate >5 mmol/L even with colectomy

🛠️ Management of C. difficile Infection (CDI)

Always isolate the patient immediately on suspicion of CDI, wash hands with 🧼 soap & water (alcohol gel does not kill spores), and use gloves + aprons. Stop unnecessary antibiotics, PPIs, and antiperistaltic agents (❌ loperamide, opioids).

• 💧 Supportive care: IV fluids, electrolyte correction, nutrition
• 🔬 Send stool for toxin A/B testing (not just C. difficile PCR)
• 🚫 Stop antimotility drugs – risk of toxic megacolon
• 🧪 Review current antibiotics and stop if possible

📊 Severity Classification

• Mild–Moderate: <5 stools/day, WCC <15, no systemic upset
• Severe: WCC >15, rising creatinine (>50% above baseline), fever >38.5°C, or evidence of severe colitis (clinical/radiological)
• Life-threatening: Hypotension, shock, ileus, toxic megacolon, or perforation

💊 First-Line Treatment (NICE 2021)

• 👉 Non-severe CDI: Vancomycin 125 mg PO QDS for 10 days
• 👉 Severe CDI: Vancomycin 125 mg PO QDS for 10 days
• 👉 Alternative: Fidaxomicin 200 mg PO BD for 10 days (preferred in high-risk or recurrent CDI)

🔄 Recurrence

• 💊 First recurrence: Fidaxomicin 200 mg PO BD for 10 days
• 💊 Multiple recurrences: Consider Faecal Microbiota Transplant (FMT)

⚠️ Life-Threatening CDI

• High-dose Vancomycin 500 mg PO/NG QDS ± rectal instillation
• + IV Metronidazole 500 mg TDS
• 🚨 Urgent surgical review: subtotal colectomy or loop ileostomy + lavage if toxic megacolon or perforation

🌟 Key Points for Exams

• Metronidazole is ❌ no longer first-line – only use if vancomycin/fidaxomicin not available
• FMT is now standard for recurrent CDI
• Ribotype 027 → associated with higher toxin production, resistance, and worse prognosis
• Infection control is as important as antibiotics to prevent outbreaks

📚 Reference

• NICE NG199: Clostridioides difficile infection (2021)
• PHE CDI Guidance