What's in a name?
Reproduced from Issue 116 of Arthritis Today
Dr Jon Packham explains seronegative spondyloarthropathy, a common but relatively unknown condition.
What is spondyloarthropathy?
When this lengthy piece of medical jargon is split into parts and translated its meaning becomes clearer.
Spondylo |
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arthro |
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pathy |
= |
= |
= |
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vertebrae |
+ |
joint |
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suffering |
The spondyloarthropathies are a family of similar diseases that usually cause joint and spine inflammation, and are quite distinct from rheumatoid arthritis. Around 1 in 100 people are affected by spondyloarthropathy, similar to the number of people with rheumatoid arthritis.
The spondyloarthropathies have several common features:
- arthritis of a few large joints such as knees and ankles
- arthritis of the spine and the sacroiliac joints (where the spine and pelvis meet)
- inflammation at the points where tendons/ligaments/joint capsule enter the bone (enthesitis)
- inflammation/involvement of other organs (eyes, large bowel and heart)
- a genetic association with HLA-B27
Dr Jon Packham treats a patient with seronegative arthropathyA number of well-established syndromes are included within the spondyloarthropathy family including ankylosing spondylitis, psoriatic arthritis, the arthritis of inflammatory bowel disease, Reiter's syndrome, chronic reactive arthritis and enthesitis related juvenile arthritis. In addition, people who have many of the common features, but don't fit into any of the established syndromes are now termed as having 'undifferentiated spondyloarthropathy'.
The phrase 'seronegative arthritis' can cause confusion because 'seronegative arthritis' can mean either patients with a spondyloarthropathy or patients with rheumatoid arthritis who happen to have a negative rheumatoid factor. Because of this, use of 'seronegative arthritis' is declining and being replaced by 'seronegative spondyloarthropathy' and 'seronegative rheumatoid arthritis' respectively.
How can it affect me?
In rheumatoid arthritis, joint damage is caused by inflammation of the joint lining (synovitis). In spondyloarthropathy it is likely that the joint damage is at the edge of the joint, caused by inflammation where the joint capsule joins the bone. This inflammation can cause joint damage, resulting in pain, deformity and loss of function. However, in the spine and sacroiliac joints where there is constant mechanical stress, as inflammation subsides a healing process occurs and new bone is formed. This new bone may cause long-term restriction of back movement.
Enthesitis (inflammation at the insertion of a tendon, ligament or joint capsule into bone) frequently occurs in many forms of spondyloarthropathy. The most commonly affected areas are the heel (plantar fasciitis), elbow (golfer's or tennis elbow) and the Achilles tendon.
Eye inflammation occurs most commonly in ankylosing spondylitis and Reiter's syndrome. This form of eye inflammation usually causes severe sharp pain with a dramatically red bloodshot eye. It normally responds well to treatment with eye drops from an ophthalmologist, but is frequently a recurring problem. Involvement of the heart is seen only occasionally and in many cases it is so mild that is difficult to detect.
The relationship between large bowel inflammation (colitis) and spondyloarthropathy is complex. In patients with established colitis between 10–20% have a large joint arthritis and fall under the spondyloarthropathy umbrella. In patients with a spondyloarthropathy and no bowel symptoms, 1 in 20 will subsequently develop symptomatic colitis. In addition, if the bowel is investigated via a flexible telescope, over 20% of individuals will have some large bowel inflammation, but not experience any symptoms.
What is the role of HLA-B27?
The cause of the spondyloarthropathies is not fully understood, but all of them share a common genetic marker, called HLA-B27, which is present in 40 to 95% of affected individuals. The role of HLA-B27 in causing disease remains elusive. Those individuals with HLA-B27 have a slightly different and if anything a more active immune response to bacteria than the general population. It may be this that puts them at higher risk of arthritis. The fact that reactive arthritis (arthritis which occurs after exposure to certain gut or urinary bacteria) has a similar clinical picture to the other spondyloarthropathies tends to support this. The presence of disease is determined not only by HLA-B27, but also by other genetic and environmental factors. A new genetic marker has recently been found by arc funded research in Oxford. Occasionally doctors do use HLA-B27 to help confirm spondyloarthropathy if the diagnosis is in doubt. In practice, the presence (or absence) of HLA-B27 in an individual does not change the way they are treated or their outcome.
How are the spondyloarthropathies treated?
Many patients with spondyloarthropathy and mild disease respond well to treatment with non-steroidal anti-inflammatory drugs (NSAIDs), regular exercise and physiotherapy. Persistent inflammation in one or two joints can often be improved by local steroid injections. Enthesitis is usually treated by a combination of physiotherapy or (in plantar fasciitis) podiatry and NSAIDs. Enthesitis may also respond to local steroid injections, although some tendon injections are not performed routinely because of the risks of tendon rupture.
Patients with severe disease often require a combination of NSAIDs and disease modifying anti-rheumatic drugs (DMARDs), which are also used in rheumatoid arthritis. Sulphasalazine, methotrexate and azathioprine are most frequently used and are beneficial to the arthritis related to spondyloarthropathy but have not been shown to change the effects of disease on the spine or sacroiliac joints.
Antibiotics have recently been shown to be of benefit in Reiter's syndrome/reactive arthritis when the bacterium triggering the arthritis is Chlamydia (most frequently found in the urinary or genital tracts). Unfortunately, antibiotics do not appear to have a role in treating reactive arthritis triggered by gut bacteria, or in the other spondyloarthropathies.
Although anti-TNF therapy is not yet licensed in spondyloarthropathy, early trials do show a beneficial effect to both peripheral arthritis and spinal symptoms. There has been some early research into the role of bisphosphonates, which may have dual benefit in the treatment of spondyloarthropathy. Bisphosphonates are normally used to treat osteoporosis, which occurs more frequently in active spondyloarthropathy. The other beneficial effect appears to be related to the anti-inflammatory effects of the bisphosphonates.
Summary
The causes of the spondyloarthropathies are gradually becoming better understood. However, this new knowledge has not yet reached a level where there are direct benefits to the patient. The recent research into the treatment of spondyloarthropathy with new drugs is exciting, but further trials are needed to confirm both their beneficial effects and safety.
- arc's booklet Blood Tests and X-Rays for Arthritis is on this site.
- Dr Jon Packham is a former arc Research Fellow, and now a consultant rheumatologist at the Haywood Hospital in Stoke on Trent.
