A chronic, usually progressive inflammatory disease, ankylosing spondylitis primarily affects the sacroiliac, apophyseal, and costovertebral joints and adjacent soft tissue. Generally, the disease begins in the sacroiliac joints and gradually progresses to the lumbar, thoracic, and cervical regions of the spine. Deterioration of bone and cartilage can lead to fibrous tissue formation and eventual fusion of the spine or peripheral joints. Prevalence of ankylosing spondylitis among whites is estimated at 0.5% to 1.0%, affecting five times as many males as females. (See Ankylosing spondylitis in women.)
Recent evidence strongly suggests a familial tendency in ankylosing spondylitis. The presence of histocompatibility antigen HLA-B27 (positive in over 90% of patients with this disease) and circulating immune complexes suggests immunologic activity. A possible link to underlying infection is being investigated.
Gender Influence: Ankylosing spondylitis in women
Progressive ankylosing spondylitis is well recognized in men, but the diagnosis is commonly overlooked or missed in women, who tend to have more peripheral joint involvement.
Secondary ankylosing spondylitis may be associated with reactive arteritis (Reiter’s syndrome), psoriatic arthritis, or inflammatory bowel disease. These disorders, together with primary ankylosing spondylitis, are usually classified as seronegative spondyloarthropathies.
Signs and symptoms
The first indication is intermittent low back pain that’s usually most severe in the morning or after a period of inactivity. Other signs and symptoms depend on the disease stage and include: