Definition

Clostridium difficile Infection (CDI):

• Bacterial infection affecting colon, caused by Clostridium difficile overgrowth.
• Linked to disrupted gut microbiota after antibiotic use.
• Ranges from mild diarrhoea to severe life-threatening colitis.

Clostridium difficile Characteristics:

• Gram-positive rod bacterium.
• Produces exotoxin causing intestinal damage and pseudomembranous colitis.
• Develops when normal gut flora suppressed by antibiotics.
• Historical association: Clindamycin.
• Current leading cause: Second and third generation cephalosporins.

Aetiology

Aetiology:

• CDI caused by Clostridium difficile bacterium.
• Bacterium produces toxins damaging the colon’s lining.
• Commonly acquired in healthcare settings, especially with antibiotic use.

Risk Factors

Risk Factors for CDI (Clostridium difficile Infection):

• Recent broad-spectrum antibiotic use.
• Older age.
• Prolonged hospitalization.
• Previous CDI episodes.
• Immunocompromised state.
• Gastrointestinal procedures or surgery.
• Use of certain medications, including proton pump inhibitors.

Pathophysiology

Pathophysiology of CDI (Clostridium difficile Infection):

• Clostridium difficile bacteria produce toxins (A and B).
• These toxins damage the intestinal lining, leading to inflammation.
• Inflammation causes symptoms such as diarrhea, mucosal injury, and colitis.
• Disruption of the normal gut microbiota, often due to antibiotic use, allows Clostridium difficile to overgrow.
• Toxins produced by the bacteria play a key role in the infection’s development and severity

Differential Diagnosis

Differential Diagnosis of CDI (Clostridium difficile Infection):

• Viral gastroenteritis
• Inflammatory bowel disease (e.g., Ulcerative Colitis, Crohn’s disease)
• Irritable bowel syndrome
• Other bacterial infections (e.g., Salmonella, Campylobacter)

Epidemiology

Epidemiology of CDI (Clostridium difficile Infection) in the UK:

• Significant healthcare-associated infection
• Incidence declining with improved infection control
• Still burdens healthcare systems, especially in elderly and immunocompromised patients

Clinical Presentation (Signs and Symptoms)

Clinical Presentation of Clostridium difficile (CDI):

• CDI can present with varying severity.
• Common symptoms include diarrhea (often watery), abdominal pain, fever, loss of appetite, and nausea.
• Severe cases may manifest with profuse diarrhea, high fever, abdominal distension, and signs of systemic inflammation.
• CDI can lead to complications like toxic megacolon, sepsis, or even death.

Additional Features:

• Elevated white blood cell count (WCC) is characteristic.
• Severity can be assessed using the Public Health England severity scale, which categorizes CDI into mild, moderate, severe, and life-threatening based on clinical parameters.

Severity Scale:

• • Mild: Normal WCC, typically 3-5 loose stools per day, or a temperature > 38.5°C.

• Severe: Increased WCC ( > 15 x 109/L) or evidence of severe colitis (abdominal or radiological signs).
• Life-threatening: Hypotension, partial or complete ileus, toxic megacolon, or CT evidence of severe disease.

Investigations

Investigations for Clostridium difficile (CDI):

• Laboratory tests: Stool tests to detect CDI toxins or bacteria.
• Test methods: Enzyme immunoassays, PCR assays.
• Severe cases may require imaging or endoscopy.

Diagnosis:

• CDI diagnosis involves detecting Clostridium difficile toxin (CDT) in stool.
• Positive Clostridium difficile antigen indicates exposure, not necessarily current infection.

Management

Management of Clostridium difficile (CDI) in the UK:

• Discontinue responsible antibiotics.
• Initiate appropriate antibiotic therapy (oral vancomycin or fidaxomicin).
• Severe cases may require hospitalization, intravenous fluids, and close monitoring.
• Consider fecal microbiota transplantation (FMT) for recurrent or refractory cases.
• Implement infection control measures in healthcare settings.

Treatment details:

• First episode: Oral vancomycin (first-line) for 10 days, oral fidaxomicin (second-line), or oral vancomycin with or without IV metronidazole (third-line).
• Recurrent episode: Occurs in around 20% of patients. Within 12 weeks of symptom resolution, use oral fidaxomicin; after 12 weeks, use oral vancomycin or fidaxomicin.
• Life-threatening CDI: Use oral vancomycin and IV metronidazole. Consider specialist advice and surgery if necessary.
• Other therapies: Bezlotoxumab (monoclonal antibody targeting CDI toxin B) may not be cost-effective for preventing recurrences according to NICE. FMT can be considered for patients with 2 or more previous episodes.

Prognosis

Prognosis:

• Prognosis varies with severity and patient’s health.
• Mild cases can resolve with treatment, severe cases can be life-threatening.
• Risk of recurrence is a concern, especially with multiple episodes or risk factors.
• Prompt diagnosis, appropriate management, and infection control measures improve outcomes.

Complications

CDI (Clostridium difficile Infection) Complications:

• Severe colitis
• Toxic megacolon (severe colon dilation)
• Bowel perforation
• Sepsis
• Death
• Recurrent episodes causing prolonged illness and higher healthcare costs