Studies of the rheumatological complications of inflammatory bowel disease (IBD; Crohn's disease and ulcerative colitis) have focused on peripheral arthritis and spondylitis, and less is known about soft tissue rheumatism, specifically the fibromyalgia syndrome (FM). Our aim was to estimate the prevalence of FM and assess pain thresholds in patients with Crohn's disease (CD) and ulcerative colitis (UC).
Seventy-two patients with UC and 41 with CD attending consecutively at the Gastroenterology Outpatient Clinic were assessed for the presence of FM and tenderness thresholds. FM was diagnosed according to the American College of Rheumatology 1990 criteria. Tenderness was measured by manual palpation and with a dolorimeter. One hundred twenty healthy subjects served as controls.
FM was documented in 30 of 113 patients with IBD (30%), specifically in 49% of patients with CD and 19% with UC (p = 0.001); in controls the rate was 0%. Subjects with CD exhibited more tenderness and reported more frequent and more severe FM associated symptoms than subjects with UC. Patients with CD had a higher tender point count, 11.3 (+/- 6.5), than those with UC, 6.4 (+/- 5.7) (p = 0.001); in healthy controls, the count was 0.1 (+/- 0.5). Tenderness thresholds (kg) were lower in CD 2.9 (+/- 1.7) than UC 3.9 (+/- 2.0) (p = 0.005) and controls 5.8 (+/- 0.9).
FM is common in IBD, particularly Crohn's disease. The lower pain threshold in Crohn's disease may suggest a disease-specific effect. Recognizing FM in patients with IBD will prevent misdiagnosis and ensure correct treatment.