In ankylosing spondylitis (AS), there is persistent inflammation of the sacroiliac joints (between the spine and back of the pelvis) and vertebrae (spinal bones). The cause of AS is unknown, but it tends to run in families.
The symptoms usually start gradually, with pain and stiffness in the hips and lower back, which are worse after resting and are especially noticeable in the early morning. Other symptoms may include chest pain, painful heels, tiredness, and redness and pain in the eyes.
Over time, the spinal inflammation may lead to permanent stiffness and spinal curvature. Treatment involves special exercises, physical therapy, and medication to relieve symptoms.