Reactive Arthritis

Reactive arthritis, referred to also as Reiter's syndrome although this name is lapsing, is an arthritic condition related to infections such as Salmonella in the gastro-intestinal system and Chlamydia in the genito-urinary system. Reactive arthritis has a strong link with a human leucocyte antigen known as HLAB27 which is well known to be related to another arthritic condition called ankylosing spondylitis. This link puts both these conditions into a group classified as seronegative spondyloarthropathies. The arthritis usually occurs with infections such as urethritis or conjunctivitis but can occur also without them.

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.

The arthritis can last longer and be more severe if the person has a strong history in the family or they are HLAB27 positive. Of those having an infection of the gut between one and four percent may develop a reactive arthritis, but this varies greatly even with the same biological agent responsible. It is not understood how the host body and the antigen react to cause the arthritic condition and the samples of joint fluids do not exhibit the infectious organisms. Antibodies have been isolated in the joints and it is possible an inflammatory condition mediated by the immune system is implicated in the development of this condition.

The self limiting nature of this kind of arthritis means that the condition settles down over a 3-12 month period whether the severity of the symptoms is greater or lower. The chance of the condition recurring is significant, with a higher incidence if a patient is positive for HLAB27, and a new episode is potentially triggered by infections or other agents. The arthritic process can be mild or can cause destructive and disabling changes in the joints in a small group of fifteen percent of sufferers. The usual age range for onset of this condition is between 20 and 40 years, gut infections giving a 50:50 male to female ratio and urogenital infections giving a 9 to 1 ratio.

Reactive arthritis usually comes on quickly as an acute presentation with patients presenting with tiredness, high temperature and a feeling of being unwell. Lower extremity arthritis of a few joints, arranged non symmetrically (unlike rheumatoid arthritis) is common. Heel pain from inflammation of the insertion of the Achilles tendon into the heel bone is common and low back pain is present in half of the patients. Lower limb joints involved in weight bearing are typically affected, with more severely affected patients exhibiting hands and feet symptoms. Back pain symptoms are commonly reported but examination shows few findings apart from a reduction in lumbar flexion.

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.