The first step in treating patients with CDAD is to discontinue the causative agent wherever possible. The choice for initial antibiotic therapy depends on the severity of disease. Oral vancomycin or metronidazole remain the mainstays of therapy for CDI, with vancomycin reserved for patients with more severe disease and/or those who have not responded to metronidazole. Metronidazole is currently favored in guidelines from the CDC on the basis of cost and concern that oral vancomycin promotes colonization with VRE.
Oral fluids (water and electrolytes) may be necessary to counteract fluid loss as a result of excessive diarrhea, which can quickly lead to dehydration. Patients with fulminant disease and toxic megacolon may require colectomy.
Recurrence of CDI is becoming an increasing problem. Most recurrences happen 7-14 days after completion of therapy, suggesting relapse rather than re-infection. If a patient develops a second episode of CDI following initial successful treatment, it is recommended that if possible, the same drug be used to treat the second episode.
Contributing factors to recurrent CDI include:
- Continuing exposure to organisms either through re-infection (via contaminated environment or poor hand hygiene) or an endogenous source, such as C. difficile spores in GI tract.
- An inability to mount an adequate anti-Toxin A IgM and/or IgG antibody response (i.e., poor host immune response); a likely reason why CDI affects an increasingly elderly population.
Unfortunately a vicious cycle can arise whereby the initial treatment prescribed, vancomycin or metronidazole, significantly disrupts normal colonic flora reducing colonization resistance and leaving the patient vulnerable to the next recurrent episode.
A new treatment alternative is the fecal transplant for patients who have suffered recurrence despite antibiotic therapy. After adequate preparation, donor feces can be given by several methods: nasogastric (NG) tube, nasoduodenal tube, enema, or colonoscopy. Derived from multiple studies, rates of success range from 91% to 93%. Guidelines include screening donors for infectious diseases, stool preparation standards, and safety measures. In many cases, pills/capsules are manufactured from feces of individual family members, who tend to share similar intestinal microbiota with the patient. This offers patients a more palatable method of ingesting the microbial flora. After concentration/preparation, the pills contain only the bacterial content of the stool, available in an alternative form from original transplant methods.
Other treatments, including the use of probiotics or anion-exchange resins to absorb toxins, may work in some cases but none work in every case.
The goal of all treatments is to reestablish normal colonic flora so as to control C. difficile (over)growth.