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.

See also: Arthritis

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.

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

Tests may include:

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