Ankylosing Spondylitis (AS) is a chronic, lifelong type of inflammatory arthridity that primarily affects the joints of the spine. It typically affects the sacroiliac joint, where the spine attaches to the pelvis, first and then starts to affect other regions of the spinal column. The exact cause of AS is unknown, however genetics is believed to play a role in its development.
Inflammation occurs as part of the disease and triggers a response for the body to lay down new bone. If left untreated this process of new bone growth may continue until the one or more of the spinal bones fuse together.
The symptoms of AS usually begin between the ages of 15 and 45 and vary from person to person. They are typically worse following rest and relieved with exercise. AS may present as episodes of acute pain followed by periods of relief, or as pain and stiffness in the back or buttocks and/or pain in the tendons and ligaments (often felt as pain the chest, back of the heel or under the foot).