Diagnosis of ankylosing spondylitis

Abstract

According to the modified New York criteria, which are still widely used, the hallmark for the diagnosis of AS has been the detection of sacroiliitis by radiographs (Figure 4.1) [2]. Sacroiliitis is graded using a scoring system as shown in Figure 4.2. A diagnosis of AS can be made if sacroiliitis grade 2 bilaterally or grade 3 or higher unilaterally is present together with one clinical criterion, such as the presence of the clinical symptom inflammatory back pain or restriction of spinal mobility. As spinal involvement with the development of syndesmophytes normally occurs later in the course of the disease and as the spine is rarely affected without the sacroiliac (SI) joint, radiographic changes of the spine are not part of these diagnostic criteria. Examples of normal and abnormal sacroiliac joints are shown in Figures 4.3–4.5.