Ankylosing Spondylitis is a chronic inflammatory disease that affects the joints and spine. It is a type of arthritis of the spine. It literally means “inflammatory stiffening of the spine.” It typically occurs more in men than women, and usually in young adults, ages 17-35 years old. It is not hereditary; however, primary relatives have an increased risk of developing ankylosing spondylitis.
The disease usually begins with pain and stiffness in the sacroiliac joints, or the hips, then gradually progresses up the spine. The inflammatory process specifically occurs in the hip joints as well as the small joints of the spine between the vertebrae. This inflammation results in thickening of ligaments and calcification or hardening of intervertebral discs, as well as demineralization of the vertebrae. These changes in the spine cause stiffening and limitation of movement.
A diagnosis is made when lower back pain is present for at least three months. It is characterized by morning stiffness with improvement throughout the day. It also improves with exercise and movement. It is not relieved by rest, and there is usually no sharp pain radiation down the legs. There can also be limitation of chest expansion. The changes in the spine can lead to a straightening of the normal lumbar curve and an exaggeration of the thoracic curve. The patient with long standing disease may have kyphotic deformities leaving them bent forward.
An X-ray of the spine can show erosion of the vertebrae and sacroiliac joints as well as hardening and calcification of discs and ligaments. In later disease, the spine appears as a "bamboo" on X-ray. An MRI can be performed to rule out other causes of back pain, such as herniated discs.
Treatment is initiated with non-steroidal anti-inflammatory drugs such as indomethacin, and sometimes high doses of ibuprofen. For more severe symptoms, a special class of drugs call TNF-inhibitors such as etanercept and inflixumab can be employed. For complications of the disease, surgical decompressive laminectomy and spine fusion can be done to alleviate pain. Typically noncomplicated disease can be treated with medications for an improved outcome.
Lindsey Parker PA-C and Justin F. Fraser MD
McPhee, S.; Papadakis, M.; Tierny, L. (2008). Current Medical Diagnosis and Treatment. 47th edition. McGraw Hill-Medical.
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