Ankylosing Spondylitis Case Discussion

Case
A 34-year-old white man complains of neck pain. At the age of 22, the patient first noted low back, buttock, and spine pain. He had been involved in a motor vehicle accident to which he attributed some of his back pain. At that time, he saw a number of physicians who diagnosed mechanical LBP and recommended bed rest. However, he found this only seemed to make his back and buttock pain worse. Typically, he was very stiff in the
morning for more than 2 hours but in the afternoon he felt better with movement and exercise. He also noted increasing fatigue and some mild weight loss. Ten years ago, his right hip started hurting. Eight years ago, pain suddenly developed in his right eye. He saw an ophthalmologist who diagnosed acute iritis and placed him on steroid eye drops. Two years ago, his knees started to swell intermittently. His lumbar and thoracic spine regions became fused and to stand up and look straight ahead he had to bend his knees. He finally had to quit his job as a truck driver because it required prolonged sitting that made his back pain and stiffness worse.
Musculoskeletal examination reveals no obvious swelling in any joint. No movement in the lumbar or thoracic spine is noted while the patient is bending over. His right hip is found to be painful on flexion with internal rotation.
Radiographic studies of the lumbosacral spine are obtained and interpreted to show almost complete obliteration of both sacroiliac joint spaces. The posterior elements in the distal lumbar area are also found to be obliterated, together with bridging or “bambooing” of the spine. A chest radiographic study shows squaring of the thoracic vertebrae with significant syndesmophyte formation.
Where is the primary site of disease in AS?
What organs can be involved in AS, and what are the clinical manifestations?
What are three characteristic clinical findings in patients with AS that help distinguish it from RA?
What is the characteristic family history, gender incidence, and human lymphocyte antigen (HLA) pattern found in the context of AS?
What types of treatment are helpful in AS?

Case Discussion
Where is the primary site of disease in AS?
In AS, inflammation occurs at the insertion of a ligament, tendon, or articular capsule into bone, a structure known as the enthesis. The cause of this localized inflammation remains unknown. Sites of enthesopathy in AS include the sacroiliac joints; ligamentous structures of the intervertebral discs, manubriosternal joints, and symphysis pubis; ligamentous attachments in the spinous processes, the iliac crests (whiskering), trochanters, patellae, clavicles, and calcanei (Achilles enthesitis or plantar fasciitis); and capsules and intracapsular ligaments of large synovial joints. Inflammation can also be seen in the synovium, the tissue lining the joints.
What organs can be involved in AS, and what are the clinical manifestations?
Ocular involvement presents as anterior uveitis (25% to 40% of patients); secondary glaucoma and cataracts can also occur. Cardiac involvement includes aortic insufficiency, aortitis, conduction abnormalities, diastolic dysfunction, and pericarditis. Pulmonary involvement includes upper lobe fibrosis and restrictive changes. Renal involvement includes IgA nephropathy, secondary amyloidosis, and chronic prostatitis. Peripheral joint involvement (particularly hips and shoulders) can occur in approximately 30% of patients. Significant spinal osteoporosis can occur. Neurologic involvement includes atlantoaxial subluxations and cauda equina syndrome.

What are three characteristic clinical findings in patients with AS that help distinguish it from RA?
The three clinical manifestations characteristic of AS are inflammatory arthritis of the spine, Achilles tendinitis, and plantar fasciitis. These three findings are extremely rare in patients with RA.
What is the characteristic family history, gender incidence, and HLA pattern found in the context of AS?
Typically, there is a family history of AS, particularly in male family members. In fact, it occurs more commonly in men than women (3:1). This disease is very highly associated with the presence of HLA-B27. Two percent of HLA-B27–positive persons develop AS. Among those HLA-B27–positive persons with an affected first-degree relative, the rate rises to 15% to 20%.
What types of treatment are helpful in AS?
The treatment of AS includes nonsteroidal antiinflammatory drugs (NSAIDs), extension exercises for the back, and physical therapy. It is recommended that all three forms of therapy be used in affected patients. It is thought that extension exercises for the back may help patients maintain a more normal upright posture as the back fuses over time. Sulfasalazine or low-dose weekly methotrexate (MTX) therapy may be beneficial in patients having progressive disease with peripheral arthritis but does not alter the sacroiliitis. Oral corticosteroids are of no value. Local corticosteroid injections may be useful in the treatment of enthesopathies and recalcitrant peripheral synovitis. The tumor necrosis factor α (TNF-α) blocking drugs are very effective in AS, act on both spinal and peripheral joints, and may possibly delay or prevent spinal ankylosis (treatment results in improvement in magnetic resonance imaging (MRI) appearance of enthesitis and sacroiliitis). The use of anti-TNF agents should be considered in patients with active AS who have failed to respond to two or more NSAIDs for axial disease and one or more disease-modifying antirheumatic drug (DMARD) for peripheral arthritis.