Spondyloarthritis may occur in association with inflammatory bowel disease (IBD), of which ulcerative colitis and Crohn disease represent the majority of cases. Males and females are equally affected, although spondylitis is more common in men, and onset can be from childhood to adulthood. Ulcerative colitis is characterized by inflammation of the gastrointestinal mucosa with diffuse involvement of the colon. Crohn disease, also known as regional enteritis, granulomatous ileocolitis, or granulomatous colitis, is a focal granulomatous disease that can affect both the large and small intestines. Symptoms of both ulcerative colitis and Crohn disease include diarrhea (with or without bleeding) and cramping abdominal pain. Arthritis tends to occur more frequently in patients with large-bowel involvement or with extraenteric findings such as erythema nodosum (see Fig 9-3), stomatitis, or uveitis. HLA-B27 prevalence is as high as 75% in patients with axial involvement and is somewhat lower in those with primarily peripheral disease.
Radiographic findings of axial involvement are similar to those of AS but are of limited value in diagnosing early disease. MRI may also be helpful in demonstrating abnormal axial and sacroiliac findings in symptomatic patients. Elevated acute phase reactants, including ESR and CRP, often indicate heightened gastrointestinal (GI) inflammation but have limited benefit in assessing peripheral arthritis or spondylitis activity.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.