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Summary
Reactive arthritis is a seronegative spondyloarthropathy that typically develops after a genitourinary or gastrointestinal infection. The classic triad of symptoms are arthritis, urethritis and conjunctivitis.
Aetiology
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Reactive arthritis (formerly known as Reiter’s syndrome) is a seronegative spondyloarthropathy (alongside psoriatic arthritis, ankylosing spondylitis and enteropathic arthritis). It is a sterile inflammatory arthritis, occurring as a CD8 T-cell-mediated autoimmune response to an infection elsewhere in the body, typically a gastrointestinal (GI) or genitourinary (GU) infection. The term ‘sterile’ means an infectious organism cannot be recovered from the joint.
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The organisms most commonly associated with reactive arthritis are summarised in the table below.
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Around 75% of patients with reactive arthritis are positive for HLA-B27.
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Clinical features
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Reactive arthritis is described as a classic triad of:
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- Urethritis
- Conjunctivitis – usually mild, bilateral and mucopurulent with a papillary and/or follicular reaction. It self-resolves within 7-10 days, and treatment is not required. Conjunctivitis usually follows urethritis but precedes arthritis.
- Arthritis – typically an asymmetrical, migratory lower limb oligoarthritis. Two to four joints tend to be involved, most often the knees, ankles and toes
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A useful way to remember the triad of reactive arthritis is “can’t see (conjunctivitis), can’t pee (urethritis), can’t climb a tree (arthritis)”
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These symptoms typically develop within 4 weeks of the initial infection, and generally last 4-6 months. Around 1 in 4 patients will have recurrent episodes, and 10% develop chronic disease. It is important to note that not all patients present with this triad, and other features may be present:
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- Malaise
- Fever
- Ocular features: acute anterior uveitis (occurs in 20%), iritis, episcleritis
- Dactylitis (inflammation of a digit)
- Enthesitis (inflammation of the insertion sites of tendons/ligaments to bone)
- Spondyloarthritis (manifesting as lower back pain) affects 〜1/2 of patients
- Mucocutaneous lesions: keratoderma blenorrhagica (waxy brown plaques/papules on the soles of feet and palm of hands); circinate balanitis (painless vesicles on the foreskin secondary to chlamydia); and painless oral ulcers
- Genitourinary involvement: cervicitis, prostatitis, epididymitis
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Investigations
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- Bloods: ↑ESR, ↑CRP, HLA-B27 (positive in 〜75%)
- Synovial fluid is sterile
- Stool culture (if diarrhoea present)
- Urine chlamydia PCR (if GU infection suspected)
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Management
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Treating the original infection has little effect on the development of reactive arthritis. Management focuses on providing symptomatic relief:
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- 1st-line: NSAIDs
- 2nd-line: steroids (topical/intra-articular injections)
- Splints, heel pads or shoe inserts (insoles)
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If symptoms persist for more than 6 months, disease-modifying anti-rheumatic drugs (DMARDs) such as sulfasalazine or methotrexate can be tried
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Prognosis
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The prognosis of reactive arthritis is variable.
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- Symptoms usually last from 3-12 months, and may have a relapsing course
- In around 30-50% of patients, symptoms may return later or become a chronic (greater than 6 month) long-term problem,
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Risk factors for poor prognosis:
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- Presence of HLA-B27
- Persistent infection with Chlamydia
- Male gender
- Recurrent arthritis
- Family history of the disease
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References
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- Salmon, John F., and Jack J. Kanski. Kanski’s Clinical Ophthalmology: A Systematic Approach. Ninth Edition, Elsevier, 2020.
- ‘Reactive Arthritis’. Nhs.Uk, 23 Oct. 2017, https://www.nhs.uk/conditions/reactive-arthritis/.
- ‘Reactive Arthritis’. NORD (National Organization for Rare Disorders), https://rarediseases.org/rare-diseases/reactive-arthritis/. Accessed 19 Dec. 2022.
- Reactive Arthritis – General Practice Notebook. https://gpnotebook.com/en-gb/simplepage.cfm?ID=x20150606185447891848. Accessed 19 Dec. 2022.
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