Reactive Arthritis

Synonym: Reiter syndrome

Triad of non-gonococcal urethritis, conjunctivitis, and arthritis associated with gastrointestinal infections (e.g. Shigella, Salmonella and Campylobacter) or genitourinary infections (especially Chlamydia trachomatis). There appears to be a strong association with HLA B27 (~75%) and the seronegative arthropathies. The syndrome is sometimes subdivided into 2 subgroups:

• Post enteric: most commonly following infection with Salmonella, Campylobacter, Shigella, Yersinia.¹
• Post venereal: following Chlamydia trachomatis infection or HIV.

• Incidence 5.0/100,000 patients aged 18-60 years.²
• Most patients are aged 20-40 and it is more common in Caucasians.
• HLA B27 is a risk factor.³

• Reactive arthritis usually develops 2-4 weeks after a genitourinary or gastrointestinal infection. About 10% of patients do not have a preceding symptomatic infection.
• The onset is most often acute, with malaise, fatigue, and fever.
• An asymmetrical predominately lower extremity oligoarthritis (usually no more than 6 joints) is the major presenting symptom.
• Low back pain occurs in 50% of patients.
• Heel pain is common because of inflammation of the Achilles or plantar aponeurosis insertions on the calcaneus.
• The complete Reiter triad of urethritis, conjunctivitis, and arthritis may occur.
• Skin (e.g. erythema nodosum, circinate balanitis), nails (dystrophic changes) and mucous membranes (mouth ulcers) may all be affected.
• Other features include:
  • Eyes: uveitis, episcleritis, keratitis, and corneal ulcerations
  • Gastrointestinal: Some patients have intermittent bouts of abdominal pain and diarrhoea - and show lesions on colonoscopy similar in appearance to inflammatory bowel disease.
  • Cardiovascular: aortitis with or without aortic regurgitation (2%), conduction defects.

• Ankylosing Spondylitis and undifferentiated spondyloarthropathy
• Gonococcal arthritis
• Gout
• Inflammatory bowel disease
• Psoriatic arthritis
• Rheumatic fever
• Rheumatoid arthritis
• Septic arthritis

• ESR and C-reactive protein are usually very high.
• Full blood count: normocytic normochromic anaemia, mild leucocytosis and thrombocytosis during the acute phase.
• HLA-B27 is positive in 65-96% of cases. Rheumatoid factor and antinuclear antibodies absent.
• Joint aspiration may be required to rule out septic or crystalline arthritis. Synovial fluid analysis in patients with reactive arthritis shows a high white blood cell count (mostly polymorphonuclear leucocytes in acute phase).
• Culture of stools, throat and urogenital tract samples in order to identify the causative organism.
• Serology for detection of Chlamydia (refer to STD clinic for further genitourinary investigation in sexually active patients).
• X-rays: normal in early stages of disease. In advanced or long-term disease, may show periosteal reaction and proliferation at sites of tendon insertion, plantar spurs, marginal erosions with adjacent bone proliferation in hands and feet, and less often show features of sacroiliitis and ankylosing spondylitis.⁴
• ECG: in patients with prolonged disease to assess for conduction disturbances.

• In acute phase, rest affected joints, aspirate synovial effusions.
• Physiotherapy.
• NSAID's, intra-articular steroids.
• Antibiotics to treat an identified causative organism. Antibiotic treatment does not change the course of reactive arthritis, even when an infective cause is identified.
• Disease-modifying antirheumatic drugs:
  • Clinical experience with DMARDs in reactive arthritis is limited.
  • Sulphasalazine has been shown to be beneficial in some patients.
  • Experiences with other DMARDs, e.g. azathioprine, methotrexate and cyclosporin, have been anecdotally reported and they may be used in patients unresponsive to standard treatments (NSAIDs and physiotherapy).
  • Antibiotics (tetracyclines) may be useful in uroarthritis but have not been successful in enteroarthritis. In more aggressive cases, or when reactive arthritis evolves towards ankylosing spondylitis, TNF-alpha blockers may represent an effective choice.⁵

• Reactive arthritis is usually self-limiting with resolution of symptoms by 3-12 months, but symptoms may persist for 12 months or more.
• About 15% of patients develop a long-term, and sometimes destructive arthritis, enthesitis or spondylitis.
• There is a high incidence of recurrence, especially in those who are HLA-B27 positive.
• Recurrence of disease may be triggered by a new infection or other stress factor.