Ankylosing spondylitis (AS) – Bechterew disease - is a rheumatic inflammatory disease involving the sacroiliac and spinal joints with manifest radiographic damage of the sacroiliac joints (SIJs). The disease symptoms in the form of back pain and stiffness typically start between 20 and 30 years of age, but may occur earlier or later. The disease is due to a rheumatic inflammation primarily involving the sacroiliac and spinal joints in addition to areas where tendons, ligaments and joint capsules are attached to bone, areas containing fibrocartilage and named entheses. Untreated, the disease often results in increasing spinal stiffness due to fusion of the joints when the inflammatory changes heal. The etiology of AS is yet unknown, but there is, among other things, a hereditary factor, since many patients have a hereditary tissue type HLA-B27. |