A guide to ankylosing spondylitis

Anywhere from 150,000 to 300,000 Canadians (up to one in 100) are believed to suffer from Ankylosing Spondylitis (AS), a chronic inflammation of the spine.

• It is three times more common in men than in women, but recent research suggests that the ratio may be much more equal: women often have much milder cases that usually escape detection.
• AS is mainly a disease of young people, often beginning before age 20 and rarely affecting people over 40. Once thought to be part of rheumatoid arthritis, we now know that it is related but separate.

• AS is a type of chronic arthritis that mainly affects the spine. (Ankylosing means stiff, spondyl refers to the spine and itis means inflammation.)
• In AS, the inflammation occurs in joints and in areas where tendons and ligaments attach to bones.
• In severe cases, inflammation of the spine can actually cause the spinal vertebrae to fuse.
• Older people who walk hunched over, looking down at the ground are usually in the late stages of AS.
• The good news is that today's treatment approaches can almost always prevent AS from becoming a disabling or crippling condition.

• As with many types of arthritis, the cause of AS is not known. But genes have a strong influence, since AS occurs primarily in people who have a genetic marker, or protein, called HLA-B27 on the surface of their white blood cells.
• Someone who carries the HLA-B27 gene has a one to two percent risk of developing AS — but the risk can rise to 20 per cent if a first-degree relative (parent or sibling) has the disease.

• AS typically begins gradually, almost insidiously. The first symptoms are usually aches and pains in the lower back caused by inflammation of the sacroiliac joints, located in the lower back on both sides of the spine, just above the buttocks (lower back pain that begins gradually and persists for months is often a tip-off for the disease).
• The backache can be quite severe, interfering with sleep and causing a person to roll sideways to avoid bending the back when getting out of bed.

• As it progresses, AS and its inflammation may move to the upper back or spread to other joints, especially the neck, hips and shoulders. The spine becomes stiff due to pain and muscle spasms.
• In the final stages of AS, chronic inflammation can cause bony bridges to form between the vertebrae, resulting in the spine fusing permanently into a bent and inflexible position.
• AS is a systemic disease, so it sometimes affects areas of the body beyond the joints.
• People with AS may experience fatigue, weight loss, poor appetite and — in about 25 per cent of patients — an inflammatory eye condition known as iritis, which causes redness and tearing.
• People with severe and long-standing AS may experience damage to heart tissue that requires the implantation of a pacemaker.