http://www.arthritis-health.com/types/ankylosing-spondylitis/ankylosing-spondylitis-overview

What is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a type of arthritis that primarily affects the back (spine). In ankylosing spondylitis, the joints and ligaments that normally let the back move become inflamed, resulting in pain and stiffness. Other joints, such as the knee and shoulder, may also become inflamed. This form of arthritis most commonly occurs in young men between the ages of 15 and 30.

Ankylosing spondylitis can also occur in women and children, although their symptoms may vary from the typical profile presented by a young adult male. More than 200,000 Americans have ankylosing spondylitis and almost everyone with this type of arthritis carries a specific gene called HLA-B27.

Diagnosing ankylosing spondylitis (pronounced ankle-low-zing spond-ill-eye-tis) can be somewhat difficult as low back pain is a common problem and initial x-ray studies are often normal.

Early diagnosis is important, and people who suffer from the joint painassociated with this disease need a comprehensive treatment plan that helps manage the pain and maintains or extends their range of motion.

If left untreated, ankylosing spondylitis can lead to deformities and chronic pain. New, effective medication is now available and can be discussed as a treatment option with your rheumatologist.

• Learn about the role of rheumatologists and other types of doctors who treat arthritis in Arthritis Treatment Specialists

Ankylosing Spondylitis is a Form of Arthritis

Ankylosing spondylitis is a type of arthritis that typically afflicts the joints in the spine and results in fusion of sections of the spine. The term “ankylosing” means “stiff” or “rigid”. “Spondyl” refers to the spine and the means of inflammation. As a result of this inflammation of the spine, the vertebrae may grow together (fuse), causing the spine to become rigid and inflexible.

The fusion is a reaction to inflammation of ligaments or tendons where they attach to bone. The bone then erodes at the site of the attachment (enthesopathy), but as the inflammation subsides, new bone grows in its place as part of the healing process. Because the new bone is rigid, and not elastic like the tissue or ligaments, spine movement is compromised.

The joint inflammation can affect different segments of the spine, causing more bone to form and fusing the individual vertebrae and joints in the spine. If the spine fuses together in a hunched forward position, internal organs such as the heart and lungs can also be affected.

In severe, advanced cases of ankylosing spondylitis there is a complete fusion of the bones of the spine, turning the spinal column into one long bone instead of a series of joints that provide a high degree of movement and flexibility in all directions.

Fortunately, for most ankylosing spondylitis patients, the disease only causes partial fusion in the spine and does not progress to the extent where their posture and form will be visibly affected. Many patients may find that the disease stops progressing and stabilizes at a certain level, with or without undergoing a specific ankylosing spondylitis treatment regimen. A minority of patients have reported that symptoms actually become less severe with age. However, limited flexibility in just one or a few segments of the spine can still lead to acute joint pain and restricted movement.