Ankylosing spondylitis is a form of arthritis that affects primarily the spine. The Spondylitis Association of America web page explains that spondylitis means inflammation of the spine, and ankylosis means fusion.
In this condition, new growth of bone in the spine causes the vertebrae to fuse into a fixed, immobile position in advanced cases. The course of the disease varies widely.
Some patients experience only mild symptoms of intermittent back pain, but others can be disabled. Most, but not all, patients have flares and remissions.
The American Autoimmune Related Diseases Association (AARDA) website describes ankylosing spondylitis as an autoimmune condition. Inflammation, pain, and stiffness in the spine and pelvic joints are the characteristic symptoms.
Some patients also experience inflammation in the eye, heart, lungs, or bowels. It usually begins between the ages of 20 and 40.
Unlike most autoimmune diseases, ankylosing spondylitis is diagnosed more often in men than in women. AARDA reports that women may be affected differently, so that doctors may fail to diagnose the disease in some women.
Structural damage to the joints is a characteristic of ankylosing spondylitis (AS), rheumatoid arthritis (RA), and psoriatic arthritis (PsA), but these different types of arthritis produce different types of damage. Georg Schett of the University of Erlangen-Nuremberg, Germany, and colleagues provided a review.
“RA, PsA, and AS differ substantially in their patterns of bone and cartilage damage,” Schett explained. “RA is typically characterized by bone erosion, whereas the main structural outcome in AS is bony spur formation based on bone formation.”
The progression of the disease can be followed radiographically by X-rays and MRI.
TNF blockers are powerful anti-inflammatory drugs that interfere with the action of tumor necrosis factor alpha. These are also called TNF inhibitors.
Schett reported that TNF blockers treat symptoms for patients with ankylosing spondylitis, but they do not influence the formation of new bone.