Thursday, August 6, 2009

Reactive Arthritis

By Jonathan Blood Smyth

Reactive arthritis is also known as Reiter's syndrome, although this latter term is losing ground gradually to reactive arthritis. It is associated with gastrointestinal infections by Salmonella and other organisms, and with genitourinary infections such as with Chlamydia. There is a significant connection with the human leucocyte antigen, HLA B27, which links reactive arthritis to other arthritic diseases such as ankylosing spondylitis which puts it in the group of conditions known as seronegative spondyloarthropathies. Although conjunctivitis and urethritis are commonly connected with this form of arthritis, the arthritis can occur without these infections.

Once a person has an infection of the genitourinary system or the gastrointestinal system then the arthritis can come on around two to four weeks later, with a respiratory infection with Chlamydia also a possible causative factor. There may be no apparent preceding infection in around ten percent of patients. Many anatomical structures can be affected by the inflammation, including the mucous membrane, the eyes, the joints, the spine, the ligament-bone and tendon-bone junctions and the gastro-intestinal system. Patients with HLAB27 are fifty times more likely to develop reactive arthritis than those without it.

Longer lasting and more damaging arthritis is suffered by those patients who are HLAB27 positive or have a strong familial tendency to this condition. From 1 to 4 percent of those suffering a gut related infection may develop reactive arthritis but this number varies greatly even with the same infecting agent. How the biological agent and the person's body react to cause the arthritis is not known and none of the infecting agents are found in the joint fluids. Immune reaction to the infectious agents does occur and antibodies have been isolated from joint fluids, suggesting this might be an immune mediated inflammatory condition.

The course of reactive arthritis tends to be self limiting with the symptoms settling down over a period from three to twelve months even in patients who are badly disabled by the arthritis. There is a significant tendency for the arthritis to recur, with recurrence higher in people who are HLAB27 positive, and recurrence can be triggered by another infection or other factor. In 15% of patients the reactive arthritis continues into a longer term and at times joint destructive arthritis or similar problem. Most patients with this condition are between twenty and forty years old, with food related infections equally shared between males and females, while urogenital infections causing arthritis are nine times more common in men.

The presentation of reactive arthritis is usually sudden and with an acute illness involving raised temperature, feeling unwell and tiredness. It is common for a small number of joints to be affected in the leg weight bearing joints, but not exclusively, with a non-symmetrical pattern. The Achilles tendon insertion into the calcaneus at the heel can suffer from inflammation and pain and around half of the patients with arthritis complain of low back pain. Usually affected joints are the weight bearing joints of the legs while feet and hands are affected in more severe cases. Few findings of relevance in spinal examination are apparent despite common back pain.

Reactive arthritis treatment is determined by how difficult the arthritic symptoms are for the patient, with a mainstay of treatment being non-steroidal anti-inflammatory drugs which are taken regularly to keep up a level of anti-inflammatory action. The maintenance and restoration of muscle power, control of pain and protection of joint ranges of motion can be effected by referral to physiotherapy. Intra-articular injections with corticosteroids are a useful treatment and can give long term relief of an inflamed joint. If anti-inflammatory drugs are not effective then systemic corticosteroids can be given and while antibiotic drugs may be prescribed at times they do not affect the disease course.

Chronic and ongoing joint arthritis and poorly limited inflammatory reactions may mean a rheumatologist will prescribe drugs known as DMARDS or disease modifying anti-rheumatoid drugs. These have been tested on conditions such as rheumatoid arthritis or ankylosing spondylitis but their usefulness in reactive arthritis has not been shown. Typical examples are methotrexate and sulphasalazine. The newer biological drug treatments have been effective in some conditions but have not yet been shown to be useful in this condition. - 14130

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