S2237 Lyme Arthritis Mimicking Inflammatory Bowel Disease-Associated Arthritis in Patient With Crohn’s Disease

Abstract

INTRODUCTION: Arthritis is a recognized extraintestinal manifestation of inflammatory bowel disease (IBD) with 6 to 46 % prevalence. It should be suspected in patients with IBD who develop joint pain, stiffness, or symptoms of inflammatory back pain. Here we describe a case of inflammatory polyarthritis in a patient with Crohn’s disease that was nonresponsive to conventional IBD treatment, later diagnosed with Lyme arthritis. CASE DESCRIPTION/METHODS: A 34 Y old man with 2-year history of ileocecal Crohn’s disease on Infliximab in clinical remission was seen for 6-month history of migratory joint pain involving multiple joints including bilateral hips, knee and ankle. CBC, ESR and fecal calprotectin were within normal limits. CRP was mildly elevated (20 mg/L, N < 10 mg/L). On examination there was joint tenderness without joint swelling. He was started on sulfasalazine 500 mg TID which was gradually increased to 1000 mg TID. This resulted with minimal improvement in joint pain. Infliximab was switched to adalimumab due to refractory joint pain. He presented 2 months later with acute swelling of left knee. Arthrocentesis was performed and synovial fluid analysis showed WBC 24,000 cells/ml and positive PCR for B. burgdorferi DNA. He was started on oral doxycycline resulting in gradual improvement in joint pain. DISCUSSION: The arthritis associated with IBD may manifest primarily with axial or peripheral joint involvement. Arthritis is usually non erosive and self-limiting. Episodes of exacerbations and remissions of synovitis may continue for years. This considerably overlaps symptoms of Lyme arthritis which includes intermittent or persistent attacks of joint swelling and pain during a period of months to several years, with few systemic manifestations. Arthritis can begin 4 days to 2 years (mean, 6 months) after the tick bite. In our case, arthritis was resistant to sulfasalazine and 2nd anti TNF. It was only after development of joint swelling, an arthrocentesis revealed diagnosis of Lyme’s disease. It is crucial to explore other causes of arthritis in patients with IBD, especially after failure to respond to initial treatment. Treatment of IBD associated arthritis includes addition of either sulfasalazine, methotrexate, azathioprine or 6-mercaptopurine. In resistant cases, TNF-alpha inhibitor can be initiated or switched to a second TNF inhibitor before trying another biologic agent, while Lyme’s arthritis is treated with antibiotics.