Case Presentation: A 21-year-old male with past medical history of Crohn’s disease on monthly infliximab infusion initially presented to the emergency department with a 5-day history of joint pain. He first noted left-sided pain that was only relieved by heat, but it progressed to left hip and groin pain made worse with movement. The patient was discharged with pain medication. He presented to the emergency department again a day later with worsening of symptoms. He was empirically started on intravenous vancomycin and piperacillin/tazobactam before admitting. Upon admission, vital signs were significant for tachycardia (110 beats/minute) but was otherwise afebrile and stable. White blood cell count was elevated at 20 g/dL. Initial concern was for septic arthritis, reactive arthritis (ReA) or inflammatory bowel disease (IBD) induced arthritis. Further investigation revealed no eye pain, eye redness, abdominal pain, tenesmus, blood in the stool, new rashes, or mucosal ulcers. The patient admitted to having increased diarrhea compared to baseline. He also denied any recent bug or tick bites. Physical examination revealed mild swelling bilaterally of wrists. Left hip pain was induced on any active movement and passive internal and external rotation. There was no joint warmth, redness or effusion. Initial pertinent negative laboratory studies included antinuclear antibody, rheumatoid factor, human leukocyte antigen-B subtype 27 (HLA-B27), iron study, blood culture, urinalysis, HIV, chlamydia and Neisseria RNA. Inflammatory markers included C-reactive protein of 89.2 mg/L and erythrocyte sedimentation rate of 7 mm/h. Bilateral hip and sacroiliac joint x-ray did not show any abnormality. Because there was no obvious evidence of infection, intravenous antibiotics were discontinued after 2 days with only minimal improvement of symptoms. Eventually, the stool sample returned positive for Clostridium difficile infection (CDI). Oral vancomycin was promptly initiated. The patient’s symptoms improved significantly over the next 2 days. Joint pain as well as wrist swelling was completely resolved and he was able to walk without pain. He was discharged home to complete a 10-day course of oral vancomycin.
Discussion: ReA is an acute inflammatory arthropathy following an infectious process such as gastrointestinal infections. The organisms that are often times responsible for ReA are Salmonella, Shigella or Chlamydia and less common in CDI. This case illustrated the potential cause of ReA from community-acquired CDI. Although community-acquired CDI are rare, patients with IBD have an increased risk for CDI, especially since those patients are often on glucocorticoids and biologics that can suppress the immune system. Patients with IBD most frequently complain of diarrhea; testing for CDI is recommended and must be a part of the differential diagnosis. The exact pathogenesis through which ReA occurs is not clear, but the systemic absorption of C. difficile toxin results in antibody production which could be the pathogenesis for ReA. It has been shown that ReA is commonly seen in young males with positive HLA-B27. The patient in focus represents a case of ReA where HLA-B27 was negative.
Conclusions: CDI is a rare cause of ReA. The many overlapping symptoms between other causes of acute arthritis in addition to the rarity of CDI-induced ReA poses a considerable diagnostic challenge. Clinicians should always consider CDI as one of the differentials in patients with diarrhea and appropriate risk factors.