Disease Reference

Ankylosing spondylitis

Definition

Ankylosing spondylitis is a long-term disease that causes inflammation of the joints between the spinal bones and the joints between the spine and the pelvis. It eventually causes the affected spinal bones to join together.

Alternative Names

Rheumatoid spondylitis; Spondylitis; Spondylarthropathy

Causes

The cause of ankylosing spondylitis is unknown, but gene problems seem to play a role.

The disease starts with intermittent hip or lower-back pain that is worse at night, in the morning, or after inactivity. Back pain begins in the sacroiliac joints (between the pelvis and the spine) and may later include the lower spine and the upper spine.

Pain may be eased by assuming a bent posture. Limited expansion of the chest occurs because of the involvement of the joints between the ribs. The symptoms may worsen, go into remission, or stop at any stage.

The disease most frequently begins between age 20 and 40, but may begin before age 10. It affects more males than females. Risk factors include a family history of ankylosing spondylitis and male gender. About 0.21% of Americans over age 15 are affected.

Symptoms

The disease starts with hip or low back pain that comes and goes and is worse at night, in the morning, or after inactivity.

Back pain begins in the sacroiliac joints (between the pelvis and the spine) and may later include the lower spine and the upper spine.

Pain may go away by bending over. You may not be able to fully expand your chest because of the involvement of the joints between the ribs.

Specific symptoms:

Chronic stooping to relieve symptoms
Eye inflammation
Fatigue
Heel pain
Hip pain and stiffness
Joint pain and joint swelling in the shoulders, knees, and ankles
Limited expansion of the chest
Limited range of motion, especially involving spine and hips
Low-back pain that is worse at night, in the morning, or after inactivity
Loss of appetite
Neck pain
Slight fever
Stiffness and limited motion in the low back
Weight loss

Exams and Tests

Tests may include:

CBC
ESR
HLA-B27 antigen
X-rays of the spine and pelvis

Treatment

Your doctor may prescribe nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and pain.

Corticosteroid therapy or medications to suppress the immune system may be also prescribed. Drugs called TNF-inhibitors, which block an inflammatory protein, have been shown to improve the symptoms of ankylosing spondylitis.

Some health care professionals use cytotoxic drugs (drugs that block cell growth) in people who do not respond well to corticosteroids or who are dependent on high doses of corticosteroids.

Surgery is done if pain or joint damage is severe.

Exercises can help improve posture and breathing. Lying flat on the back at night can help maintain normal posture.

Outlook (Prognosis)

The course of the disease is unpredictable. Symptoms may come and go at any time. Most people are able to function unless the hips are severely involved.

Possible Complications

Damage of bone and cartilage can lead to fusing of joints in the spine or other areas, which can interfere with your ability to move. It can be extremely painful and crippling. The heart, the lungs, and the eyes may also become affected.

Complications include:

Eye inflammation (uveitis)
Heart valve disease, typically aortic valve stenosis
Inflammation of the aorta
Pulmonary fibrosis

When to Contact a Medical Professional

Call your health care provider if you have symptoms of ankylosing spondylitis or if you have ankylosing spondylitis and new symptoms develop during treatment.

Prevention

Prevention is unknown. Awareness of risk factors may allow early detection and treatment.