Pathophysiology
- Antibiotics alter bacterial flora causing loose watery stools.
- Direct antibiotic effect on intestinal mucosa alters gut microbiota composition.
- Normal gut flora suppression permits pathogenic bacteria and fungi overgrowth.
- Decreased metabolism of non-digested carbohydrates and primary bile acids occurs.
- Reduced production of short-chain fatty acids exacerbates osmotic load.
Etiologic Agents
| Category | Pathogens |
|---|
| Most Common | Clostridioides difficile (C. difficile). |
| Other Organisms | Staphylococcus, Candida, Enterobacteriaceae, Klebsiella. |
Clinical Manifestations
- Disease spectrum ranges from mild diarrhea to fulminant pseudomembranous colitis.
- Mild illness features watery diarrhea, low-grade fever, mild abdominal pain.
- Severe progression exhibits abdominal cramps, fever, yellowish mucosal plaques (pseudomembranes).
- Extreme cases associate with toxic megacolon, systemic toxicity, multisystem organ failure.
Diagnostic Evaluation
| Investigation | Utility And Interpretation |
|---|
| Target Population | Testing discouraged in children <2 years due to high asymptomatic carriage. |
| Stool Assays | Multistep approach recommended combining glutamate dehydrogenase (GDH) immunoassay, toxin A/B enzyme immunoassay (EIA), and nucleic acid amplification tests (NAAT). |
| Endoscopy | Indicated for suspected pseudomembranous colitis. Reveals 2-5 mm raised yellowish plaques on colonic mucosa. |
Management Protocol
- Immediate cessation of offending antibiotic often resolves symptoms,.
- Institute specific antimicrobial therapy for severe or persistent C. difficile colitis.
Pharmacotherapy For C. difficile
| Severity/Scenario | Drug Choice And Dosage |
|---|
| First-Line (Mild-Moderate) | Oral Metronidazole 30 mg/kg/day in 4 divided doses for 7-10 days. |
| Severe/Refractory Disease | Oral Vancomycin 40 mg/kg/day in 4 divided doses (maximum 2 g/day) for 10-14 days. |
| Alternative Therapy | Fidaxomicin approved for children >6 months; efficacy equivalent to vancomycin. |
| Recurrent Disease | Pulsed-tapered oral vancomycin regimen over 4-6 weeks. Fecal microbiota transplantation utilized for multiply recurrent cases. |
Prevention Strategies
- Probiotic administration significantly reduces overall incidence.
- Lactobacillus rhamnosus GG and Saccharomyces boulardii strongly recommended for prevention.
- Saccharomyces boulardii conditionally recommended specifically for preventing C. difficile-associated diarrhea.