Ankylosing Spondylitis

What is ankylosing spondylitis?

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Ankylosing spondylitis (AS) is a type of arthritis that affects the spine. Ankylosing means stiff or rigid, spondyl means spine, and itis refers to inflammation. The disease causes inflammation of the spine and large joints, resulting in stiffness and pain. The disease may result in erosion at the joint between the spine and the hip bone (the sacroiliac joint), and the formation of bony bridges between vertebrae in the spine, fusing those bones. In addition, bones in the chest may fuse. The cause of AS is unknown, although researchers suspect genetics play a role. A gene called HLA-B27 occurs in over 95 percent of those with AS. However, some people with the HLA-B27 gene do not have AS.

Who is affected by ankylosing spondylitis?

AS is more common among young people, between ages 17 and 35, but it can occur in children and older adults as well. The disease affects two to three times more young men than women and it tends to run in families.

What are the symptoms of ankylosing spondylitis?

Symptoms of AS tend to occur and disappear over periods of time. The following are the most common symptoms of AS. However each individual may experience symptoms differently. Symptoms may include:

  • Back pain, usually most severe at night during rest

  • Early morning stiffness

  • Stooped posture in response to back pain (bending forward tends to relieve the pain)

  • Straight and stiff spine

  • Inability to take a deep breath, if the joints between the ribs and spine are affected

  • Appetite loss

  • Weight loss

  • Fatigue

  • Fever

  • Anemia

  • Joint pain

  • Mild eye inflammation

  • Organ damage, such as the heart, lungs, and eyes

  • Skin rashes 

  • Gastrointestinal illness (such as Crohn's or ulcerative colitis) 

The symptoms of ankylosing spondylitis may resemble other medical conditions or problems. Always consult your doctor for a diagnosis.

How is ankylosing spondylitis diagnosed?

In addition to a complete medical history and physical examination, diagnostic procedures for ankylosing spondylitis may include:

  • X-ray. This diagnostic test uses invisible electromagnetic energy beams to produce images of internal tissues, bones, and organs onto film.

  • Erythrocyte sedimentation rate (also called ESR or sed rate). This is a measurement of how quickly red blood cells fall to the bottom of a test tube. When swelling and inflammation are present, the blood's proteins clump together and become heavier than normal. Thus, when measured, they fall and settle faster at the bottom of the test tube. Generally, the faster the blood cells fall, the more severe the inflammation; less than 70 percent of persons with AS have an elevated ESR.

  • Genetic testing. Genetic testing is performed to determine if a person carries a copy of an altered gene for a particular disease; the specific gene (HLA-B27) is found to be present in over 95 percent of people with AS.

Treatment for ankylosing spondylitis

The goal of treatment for AS is to reduce pain and stiffness, prevent deformities, and maintain as normal and active a lifestyle as possible. Treatment may include:

  • Nonsteroidal anti-inflammatory medications (to reduce pain and inflammation)

  • Tumor-necrosis-factor blockers also known as biologic medications (may be used in progressive disease to reduce inflammation and swelling, but can increase risk of infections, especially tuberculosis)

  • Disease-modifying antirheumatic drugs (DMARDs), such as sulfasalazine, work in a number of different ways to decrease inflammation and control AS

  • Short-term use of corticosteroids (to reduce inflammation)

  • Short-term use of muscle relaxants and pain relievers (to relieve severe pain and muscle spasms)

  • Surgery (to replace a joint; to place rods in the spine; to remove parts of the thickened and hardened bone)

  • Maintain proper posture

  • Regular exercise, including exercises that strengthen back muscles