MKSAP Quiz: Low back pain

MKSAP Answer and Critique

The correct answer is A) Etanercept. This item is available to MKSAP 15 subscribers as item 71 in the Rheumatology section.

This patient most likely has ankylosing spondylitis, and the most appropriate treatment is therapy with an anti–tumor necrosis factor-α agent such as etanercept. This condition usually affects patients in the teenage years or 20s and manifests as chronic low back pain and stiffness that are alleviated with exercise.

This patient's clinical presentation is consistent with severe ankylosing spondylitis. As this condition progresses, spinal fusion and a resulting loss of spinal mobility may occur. An inability to touch a wall with the occiput when standing upright against the wall indicates a flexion deformity, and the distance between the wall and the occiput helps to measure the level of a patient's deformity. Radiographs of the spine in patients whose disease has progressed for several years typically reveal fusion of the sacroiliac joints as well as squaring of the vertebral bodies, which is caused by erosion of the corners of the vertebral bodies due to inflammation of the ligamentous attachments.

Conventional therapies such as NSAIDs are useful in relieving symptoms and in helping to maintain function in patients with ankylosing spondylitis but do not prevent progressive joint damage, bony ankylosis, physical deformity, or disability in patients with severe disease. Most patients treated with NSAIDs show significant relief of back pain within 48 hours of therapy with an optimal anti-inflammatory dose of NSAIDs and a prompt return of symptoms (within 48 hours) after discontinuation of the drug. Physical therapy and a regular exercise program have been shown to provide symptomatic relief, improve function, and increase the likelihood of a more functional posture as spinal fusion progresses. This intervention is therefore recommended in all patients with ankylosing spondylitis.

Until the advent of tumor necrosis factor-α inhibitors, no therapy had been shown to significantly and potentially affect progressive spinal fusion in patients with ankylosing spondylitis. Use of these agents usually is associated with a degree of symptomatic relief and improvement in inflammatory changes visible on MRI. To date, however, these agents have not been shown to impact progressive spinal changes.

Many of the agents used in rheumatoid arthritis, including methotrexate, sulfasalazine, and low-dose prednisone, are beneficial in the treatment of peripheral inflammatory arthritis associated with ankylosing spondylitis. However, these agents do not significantly affect spinal involvement in the spondyloarthropathies.