What Is Ankylosing Spondylitis?
Ankylosing spondylitis (AS) is a type of arthritis that inflames the joints (vertebrae) in the spine. The most commonly affected part of the spine in the sacroiliac (SI) joint. This is the joint where the spine connects with the pelvis. The condition affects other joints in the body in some cases including the ribs, shoulders, knees, hips, and feet. The condition causes pain, stiffness, and discomfort along the length of the spine. Rarely, AS involves the bowel, eyes, lungs, and heart. Many people who have AS have mild, intermittent pain. Some have constant, severe pain. Some people experience a loss of flexibility in the spine due to AS.
Spondylitis means inflammation of the spine. Ankylosis is when bones fuse together. When vertebrae become inflamed and fuse together, the condition is called ankylosing spondylitis. AS is a type of spondyloarthropathy. Spondyloarthropathies are chronic, long-term joint diseases. The spondyloarthropathies include AS, psoriatic arthritis, reactive arthritis, and enteropathic arthritis, a type of arthritis that sometimes occurs in people who have inflammatory bowel disease. The most common symptom of spondyloarthropathy is lower back pain. Spondyloarthropathies have a tendency to run in families. Another name for spondyloarthropathies is spondyloarthritis. This refers to inflammatory conditions that involve the joints and the entheses (areas were tendons and ligaments attach to bones). Spondarthropathies may mimic rheumatoid arthritis in a variety of ways. However, spondarthropathies do not feature rheumatoid factor, antibodies that are present in many people who have rheumatoid arthritis.
Spondyloarthropathies are grouped into two main classes. Axial spondyloarthritis is inflammation of the spine and sacroiliac joints. Peripheral spondyloarthropathritis is inflammation that affects the peripheral joints.
Other less common names for ankylosing spondylitis are Marie Strümpell disease and Bechterew disease.