Ankylosing spondylitis or AS, is a form of arthritis that primarily affects the spine, although other joints can become involved. It causes inflammation of the spinal joints (vertebrae) that can lead to severe, chronic pain and discomfort.
In more advanced cases this inflammation can lead to ankylosis — new bone formation in the spine — causing sections of the spine to fuse in a fixed, immobile position.This fusing makes the spine less flexible and can result in a hunched-forward posture.
AS can also cause inflammation, pain, and stiffness in other areas of the body such as the shoulders, hips, ribs, heels, and small joints of the hands and feet. Sometimes the eyes can become involved (known as iritis or uveitis), and — rarely — the lungs and heart can be affected. If ribs are affected, it can be difficult to breathe deeply.
Ankylosing spondylitis affects men more often than women. Signs and symptoms typically begin in early adulthood.
The hallmark feature of ankylosing spondylitis is the involvement of the sacroiliac (SI) joints during the progression of the disease. The SI joints are located at the base of the spine, where the spine joins the pelvis.
There is no cure for ankylosing spondylitis, but treatments can lessen your symptoms and possibly slow progression of the disease.