Symptoms of Ankylosing Spondylitis

Ankylosing spondylitis, or AS, is a chronic inflammatory arthritis which principally affects the spine and sacroiliac, or SI, joint. The disease can progress to severely limit mobility and affect the lungs and heart, but most AS patients have minimal or no disability. AS usually occurs in men between the ages of 20 and 40, although it can also occur in women and children.

Early Symptoms

AS often begins with minor but persistent lower back pain and stiffness of the SI joint. The stiffness is usually worse on wakening and eases throughout the day. It differs in intensity from day to day. A classic early symptom is pain in both heels on first stepping out of bed in the morning. Other early symptoms include diminished chest expansion, low-grade fever, fatigue, loss of appetite, weight loss and anemia.

Progression of the Disease

Over time, the stiffness of AS may progress to persistent or recurrent back pain. Skeletal changes may occur, including narrowing of the SI joints and calcification of the spinal ligaments. Syndesmophytes--bone "bridges" between vertebrae--may form, impairing movement of the spine. The vertebrae themselves may take on a squared shape due to loss of minerals. The combination of syndesmophytes and squared vertebrae is known as "bamboo spine" when seen on X-rays. In the most severe cases, the spine becomes permanently flexed forward due to back pain and muscle spasms, and the patient is no longer able to stand upright.

Systemic Symptoms

About one-third of patients experience systemic symptoms. These include inflammation of the eye, called anterior uveitis; cardiac symptoms such as angina and inflammation of the pericardium; and in rare cases, fibrosis of the upper lobe of the lung.

Neurological Symptoms

The spinal changes in AS can cause compression of the nerves. Sciatica and radiating pain are common. If the lower end of the spinal cord is damaged, cauda equina syndrome may result. This serious condition consists of impotence, diminished bladder control and absence of the ankle reflexes.

Prognosis

In most cases of AS, recurrent back pain and stiffness are the only symptoms, and inflammatory symptoms alternate with periods of little to no pain. In severe cases, the disease progresses over time, resulting in spinal deformity and disability.

Treatment

The joint pain of AS is usually treated with a combination of non-steroidal anti-inflammatory drugs or other anti-inflammatory measures. This is coupled with daily exercises and therapy that encourage proper posture and mobility of the joints. Strengthening the extensor muscle groups--those that pull the spine up and back--is especially important, as these muscles help counteract the forward flexion of spinal deformities in AS.

Resources

• Spondylitis Association of America