The patient presented to the ED with vomiting and an exacerbation of abdominal pain from which he had been suffering for two weeks.

From the patient's file: Diagnosis of ankylosing spondylitis. Multiple episodes of abdominal pain, vomiting, and diarrhea for the past 3 years; suboptimal preparation for colonoscopy half a year ago. Fistulectomy for trans-sphincteric perianal fistula several months earlier. Leukocytosis of 14K, CRP 120.

CT abdomen showed all the hallmark radiological signs of both Crohn disease and ankylosing spondylitis.

Had been receiving Enbrel (etanercept) for 4 years. Started on Humira (adalimumab), which is efficacious for both conditions.

There is a known association between HLA-B27 and both inflammatory bowel disease (IBD) and ankylosing spondylitis (AS). This may explain IBD-associated spondyloarthropathy (SpA).

Disclosure: I, Dr Yair Glick, have no actual or potential ethical or financial conflict of interest in relation to the abovementioned medications. This case is not intended to be a personal endorsement or recommendation of these products.