Ankylosing Spondylitis

Definition

Ankylosing Spondylitis is an inflammatory disease of unknown origin, first affecting the spine and adjacent structures, and commonly progressing to eventual fusion (ankylosis) of the involved joints.

In extreme cases, the patient develops a forward flexion of the spine, called a "poker spine" or "bamboo spine."

Description

Ankylosing spondylitis (AS) is a chronic form of arthritis that falls into the category of the spondylarthropathies, or arthritis that affects primarily the spine.

In people with AS, the joints and ligaments that permit normal movement of the back become inflamed, producing pain and stiffness, usually beginning in the lower back, and often progressing into the upper spine, chest, and neck. As a result, the vertebrae may fuse, causing the spine to become rigid. Other joints such as the hips, shoulders, knees, or ankles may also be involved. Recent evidence strongly suggests a familial tendency in AS.

Typically the disease begins in the lower back and progresses up the spine to the neck. Deterioration of bone and cartilage can lead to fibrous tissue formation and eventual fusion of the spine or peripheral joints. AK is diagnosed more often in men but may be equally prevalent in both sexes. Diagnosis is often overlooked or missed in women, who tend to show more peripheral joint involvement.

Causes and Risk Factors

The disease primarily affects males under 30 years of age and generally burns itself out after a course of 20 years. The presence of human leukocyte antigen B27 (found in over 90 percent of people with this disease) and circulating immune complexes suggests immunologic activity. However, the actual relationship between the gene and the disease's development has been difficult to conform. The gene has been associated, but not linked, with the development of the spondylarthropathies.

Symptoms

The first symptom is intermittent low back pain that is usually most severe in the morning or after inactivity. Other symptoms depend on the disease stage, and may include:

• Stiffness and limited motion of the lumbar spine

• Pain and limited chest expansion caused by involvement of the costovertebral joints

• Arthritis involving shoulders, hips and knees

• Kyphosis (curvature of the spine) in advanced stages, caused by chronic stooping to avoid symptoms

• Hip deformity with limited range of motion

• Tenderness over the inflammation site

• Mild fatigue, fever, loss of appetite or weight

These symptoms progress unpredictably and the disease can disappear temporarily or permanently at any time.

Treatment

Physical therapy helps considerably in the treatment of AK to prevent the characteristically stooped posture as the spine begins to fuse. No treatment stops the progression of the disease so that management aims to delay further deformity by enforcing good posture, stretching, and deep-breathing exercises and, in some people, wearing braces and lightweight support.

The pain and stiffness may be relieved by analgesics and nonsteroidal anti-inflammatory drugs (NSAIDS). These may include aspirin, Indocin, Anaprox, Tolectin, and Clinoril. Indocin is often the NSAID of choice. NSAIDS represent the mainstay of treatment but may be discontinued due to adverse reactions or lack of efficacy.

Oral prednisone (a corticosteroid) rarely produces any benefit but intra-articular (injections into the joints) corticosteroid injections are occasionally helpful. Methotrexate is a promising agent for treatment of patients who have prominent extra-spinal involvement.

Questions to Ask Your Doctor

Are further diagnostic tests required?

What do you recommend to help with the stiffness and limited motion?

Would physical therapy be helpful?

Will you prescribe anti-inflammatory drugs?

Is there a problem with adverse reactions?

Would other drugs such as methotrexate or prednisone be of value?