[Silent axial arthropathy in inflammatory bowel disease. Clinical, radiological and genetic characteristics].

OBJECTIVES: To evaluate the prevalence, clinical and radiological characteristics, association with HLA B27 in a subgroup of patients with inflammatory bowel disease (IBD) and subclinical sacroileitis. The sensitivity of the diagnostic criteria for spondyloarthropathy in this group of patients is evaluated. MATERIALS AND METHODS: All patients with inflammatory bowel disease attending an outpatient gastroenterology unit from January 1994 to June 1994 were recruited. A total of 62 patients with IBD and without clinical evidence of axial involvement were included in the study. The demographic, clinical, and radiological characteristics were collected. The radiological examination included PA and lateral views for the dorso-lumbar, and three views (Ferguson, right and left oblique views) for the sacroiliac joints. Films were interpreted by three independent readers. The HLA B27 allele distribution was analyzed in the 62 patients and in 80 healthy controls. The modified New York criteria, Amor criteria, and European Spondyloarthropathy Study Group criteria were evaluated. Patients were prospectively followed for two years with the same initial protocol. The statistical management of data was performed with the information program SPSS/PC. RESULTS: Fifteen cases of silent sacroileitis were detected, and most of them were grade 2 unilateral sacroileitis. There was no correlation between sacroileitis and IBP type, extradigestive symptoms, disease duration, sex, or peripheral arthritis. The frequency of HLA B27 in the sacroileitis group was 20% (p < 0.05). During the two-year follow-up period none of these cases has changed from diagnostic category. The sensitivity of diagnostic the criteria for spondyloarthropathy was low in these patients (40%-53%). CONCLUSIONS: A high frequency of asymptomatic sacroileitis in patients with IBD was detected. We propose the term Silent Axial Arthropathy to define this category of patients and, as with other authors, we consider this is a third form of rheumatic syndrome in IBD, different from the classical forms of peripheral arthritis and ankylosing spondylitis.