Ankylosing Spondylitis Signs and Symptoms

Patients with ankylosing spondylitis most often have lower back pain. The pain is located over the sacrum (the bottom of the spinal column) and may radiate to the groin and buttocks and down the legs. The typical patient is a young man who experiences repeated episodes of back pain that wake him at night along with spinal stiffness in the morning. The low back pain persists even while at rest. This pain pattern is characteristic of bilateral sacroiliitis (inflammation of the sacroiliac joints).

With time, the back pain progresses up the spine and affects the rib cage. Chest expansion then becomes restricted. The patient must practice breathing using the diaphragm. The neck part of the spine (cervical spine) stiffens late in the course of the disease, leading to restriction in neck movement and head rotation. Eventually, the spine is completely rigid and loses its normal curvatures and movement.

The earliest objective sign of spinal involvement is the loss of side-to-side movement of the lower part of the spine (called the lumbar spine). The doctor may detect sacroiliitis in the patient if (1) tapping on the area over the sacroiliac joints causes tenderness or if (2) pushing on the pelvis with the patient lying face down causes pain. Several tests have been designed to measure the spinal restriction that occurs as the disease progresses. The doctor may encounter synovitis (inflammation of a membrane of a joint) and joint motion restriction while examining joints in the patient's limbs.