A 36-year-old woman with ankylosing spondylitis (AS) and a 12 year history of moderate, extensive ulcerative colitis (UC) was evaluated for active symptoms after a 15 month hiatus. Prior therapy included mesalamine and infliximab; the latter led to clinical improvement but was discontinued after a severe infusion reaction. Evaluation revealed active moderate UC, and vedolizumab therapy was initiated with induction doses at weeks 0 and 2. At week 5, she developed ascending bilateral upper extremity paresthesias, muscle weakness and headaches.