Both these conditions are considered forms of arthritis because they affect the bones and involve inflammation. Both affect the spine although ankylosing spondylitis (AS) damages the entire spine from top to bottom. Rheumatoid arthritis (RA) is more likely to affect the neck (cervical spine) and smaller joints of the hands and feet.

The inflammatory process in the body is very similar. But that's where the similarities end. The effects of the inflammation are very different from AS to RA.

In rheumatoid arthritis the lining of the joints is affected first. Then the cartilage protecting the bone starts to wear away. Next comes the top layer of bone (subchondral bone) just under the cartilage. The result is a weakened, unstable and usually painful joint.

AS causes inflammation where the muscles and tendons attach to the bone. The body tries to repair itself in these areas causing stiffness of the soft tissues and fusion of the bones. The spine becomes rigid but brittle. Patients with AS are at risk for fractures and damage to the spinal cord.

The good news for both you and your grandson is that there are new and better medical therapies for both conditions. Medication can help prevent the progression of both RA and AS.