Describe Pseudomembranous Colitis in detail.

The Concept

Pseudomembranous colitis is a colitis caused by overgrowth of the toxin-producing bacterium Clostridioides difficile. The mechanism is a disturbed ecosystem: antibiotics disrupt the normal protective gut flora, allowing C. Difficile to proliferate and release toxins A and B, which damage the colonic mucosa and produce the characteristic inflammatory 'pseudomembranes'. The classic culprit antibiotics are clindamycin, cephalosporins and fluoroquinolones, though almost any antibiotic can be responsible.

Clinical Features

It presents with profuse watery diarrhoea, crampy abdominal pain, fever and a raised white cell count, typically during or shortly after a course of antibiotics, often in a hospitalised or elderly patient. At colonoscopy the mucosa is studded with raised yellowish-white plaques (pseudomembranes). Severe disease can progress to toxic megacolon and perforation.

Diagnosis & Management

Diagnosis is by detecting C. Difficile toxin (or its gene by PCR) in the stool. Management begins with stopping the offending antibiotic where possible and instituting infection-control measures (isolation, hand hygiene with soap and water). Specific treatment is oral vancomycin or fidaxomicin (oral metronidazole for milder cases). Recurrent disease may be treated with a faecal microbiota transplant to restore normal flora, and fulminant colitis with megacolon may require colectomy.

Prevention & Infection Control

Because C. Difficile is a spore-forming, easily transmitted hospital pathogen, prevention is central: prudent 'antibiotic stewardship' (avoiding unnecessary broad-spectrum antibiotics), isolating affected patients, and hand-washing with soap and water (alcohol gel does not kill the spores). These measures limit both individual disease and hospital outbreaks, making pseudomembranous colitis as much an infection-control topic as a clinical one.

The Bottom Line

Pseudomembranous colitis is antibiotic-associated C. Difficile toxin colitis, diagnosed on stool toxin, treated by stopping the antibiotic and giving oral vancomycin/fidaxomicin with strict infection control.

A Note on Severity Assessment

Severity is graded (by white cell count, creatinine, temperature and albumin) because it guides both drug choice and the need for surgery. Fulminant disease with toxic megacolon, perforation or shock is a surgical emergency requiring colectomy, whereas most cases respond to medical therapy — so recognising the severe end of the spectrum early is what prevents disaster.

Stop the offending antibiotic and treat with oral vancomycin.

• Pseudomembranous colitis = C. Difficile toxin overgrowth after antibiotics disrupt normal flora (classically clindamycin, cephalosporins, fluoroquinolones).
• Profuse watery diarrhoea, cramps, fever, raised WCC; yellow pseudomembranes at colonoscopy; can cause toxic megacolon/perforation.
• Diagnose by stool C. Difficile toxin/PCR.
• Stop the offending antibiotic + infection control (isolation, soap-and-water hygiene); treat with oral vancomycin or fidaxomicin (metronidazole if mild).
• Recurrent disease → faecal microbiota transplant; fulminant → colectomy.