Case 15 Discussion, Part 1: Diagnosis of C. difficile infection in IBD
(The case continues after this discussion. Please click on the link following the discussion to continue on to the next part)
Diagnosing Clostridioides (formerly Clostridium) difficile infection (CDI) in patients with IBD can be a challenge because of overlapping symptoms. Both CDI and IBD flare can result in diarrhea, abdominal discomfort, and fever. Additionally, both entities can result in an elevated fecal calprotectin. While this patient had an antibiotic exposure, patients with IBD may have CDI even without antibiotic exposure due to the presence of colonic dysbiosis. CDI should be routinely tested in patients with IBD who have worsening symptoms. In addition, the use of immunosuppressive medications can predispose IBD patients to infection, especially corticosteroids. The prevalence of CDI in the IBD population is up to 8-fold higher than patients without IBD with a 10% lifetime chance of getting the infection (Hourigan et al., Dig Dis Sci 2014).
The combination of IBD and CDI is associated with increased adverse outcomes including prolonged hospital stay, decreased response to medical therapy, increased need for colectomy or other gastrointestinal surgeries, increased mortality, increased subsequent IBD flares, increased CDI recurrences, and increased need to escalate IBD therapy. (Khanna et al., AGA Institute 2017).
All patients with IBD who present with worsening of underlying diarrhea or symptoms suggesting a colitis flare should be tested for the presence of CDI. A multi-step algorithm for testing for CDI is recommended to improve sensitivity and specificity (ie, glutamate dehydrogenase [GDH] plus toxin; GDH plus toxin arbitrated by nucleic acid amplification test [NAAT] or NAAT plus toxin) (McDonald et al., Clin Infect Dis 2018).
The diagnosis of CDI in a patient with IBD may also indicate uncontrolled IBD. When a diagnosis of CDI is made, it is appropriate to treat the infection. However, if there is no clinical response to treatment, endoscopic evaluation of IBD disease activity is warranted, and may guide a change in IBD-directed therapy. Additionally, patients with IBD are at greater risk for recurrent CDI compared to patients without IBD – as high as 40% after a first episode of CDI, almost double that seen in non-IBD patients (Binion et al., Gastroenterol Hepatol 2012).