What is the appropriate diagnosis and treatment for a young adult with suspected reactive arthritis following a recent infection?

Reactive Arthritis: Diagnosis and Treatment

Immediate Diagnostic Approach

Reactive arthritis is diagnosed clinically based on acute oligoarticular arthritis of large joints developing within 2-4 weeks of a preceding genitourinary or gastrointestinal infection, with asymmetric joint involvement being the hallmark presentation. 1, 2, 3

Key Clinical Features to Identify

• Joint pattern: Asymmetric oligoarthritis primarily affecting large joints (knees, ankles) with pain, swelling, and stiffness after inactivity 3, 1
• Timing: Arthritis develops 2-4 weeks after the triggering infection (note: 25% of infections may be asymptomatic) 1, 2
• Enthesitis: Inflammation at tendon/ligament insertion sites is common 3
• Extra-articular manifestations: Conjunctivitis/uveitis and urethritis may be present 3, 4

Critical Distinction from Acute Rheumatic Fever

You must differentiate reactive arthritis from poststreptococcal reactive arthritis (PSRA) and acute rheumatic fever (ARF), as the latter carries significant cardiac morbidity and mortality risk:

• PSRA/Reactive arthritis: Cumulative and persistent arthritis occurring ~10 days post-streptococcal pharyngitis, involves large AND small joints or axial skeleton, does NOT respond to aspirin 5, 6
• Acute rheumatic fever: Migratory polyarthritis occurring 14-21 days post-pharyngitis, involves ONLY large joints, responds dramatically to aspirin within 24-48 hours 5, 7

If there is any suspicion of ARF based on timing and joint pattern, immediately evaluate for carditis with clinical examination and echocardiography, as cardiac involvement determines both prognosis and potentially lifelong prophylaxis requirements. 7

Diagnostic Workup

Identify the Triggering Infection

• Urogenital tract: Culture or ligase chain reaction for Chlamydia trachomatis 1, 2
• Gastrointestinal tract: Stool cultures for Salmonella, Shigella, Yersinia, Campylobacter 1, 8
• Serological testing: If cultures are negative (common after arthritis onset), use serological tests to demonstrate evidence of previous infection 1

Additional Testing

• HLA-B27: Can be considered for prognostic information but should NOT be used as a diagnostic tool for acute reactive arthritis, as negative results do not exclude the diagnosis 3, 2
• Inflammatory markers: ESR and CRP to assess disease activity 1
• Joint aspiration: To exclude septic arthritis and crystal-induced arthropathies (gout, pseudogout) 6, 8

Treatment Algorithm

Acute Phase (First 6 Months)

1. NSAIDs as first-line therapy 8, 9

• High doses of potent NSAIDs for symptomatic relief
• Continue until symptoms resolve

2. Local measures 8

• Arthrocentesis for large effusions
• Cold pads and rest of affected joints
• Intra-articular corticosteroid injection for large-joint involvement 9

3. Antibiotic therapy (infection-specific) 8, 2, 9

For Chlamydia-induced reactive arthritis with positive cultures:

• Doxycycline 100mg twice daily for 10-14 days 8, 9
• Alternative: Erythromycin 500mg four times daily for 10-14 days 8
• Alternative: Azithromycin 1g single dose 8
• Treat sexual partners concurrently to prevent reinfection 8

For enteric reactive arthritis (Salmonella, Shigella, Yersinia, Campylobacter):

• Antibiotics are NOT effective and should NOT be used 8, 9

Special consideration: For Chlamydia-induced reactive arthritis without positive cultures but with evidence of persistent chlamydia antigens, prolonged antibiotic treatment for 3 months may provide some benefit, though further studies are needed 8, 2

Chronic Phase (>6 Months Duration)

If arthritis persists beyond 6 months, add sulfasalazine 2g/day in addition to continued NSAIDs. 8

• Sulfasalazine is moderately superior to placebo in controlled studies and well tolerated 6, 8
• Other DMARDs can be tried in individual patients who do not respond to sulfasalazine, though no controlled studies support their use 8

Monitoring and Follow-up

Cardiac Surveillance for PSRA

If the patient has poststreptococcal reactive arthritis, observe carefully for several months for clinical evidence of carditis, as PSRA may occasionally progress to valvular heart disease. 5, 6

• Serial cardiac examinations 7
• Repeat echocardiography 7
• Monitor for new murmurs, pericardial friction rubs, or signs of heart failure 7

If valvular disease is detected, reclassify as acute rheumatic fever and initiate long-term secondary prophylaxis with penicillin V 250mg twice daily. 5, 7

Ophthalmologic Evaluation

• Patients with conjunctivitis or uveitis require ophthalmologic evaluation 3

Prognosis

• Long-term outcome is usually good 1
• 25-50% of patients develop recurrent acute arthritis, depending on triggering infection and possible new infections 1
• 25% progress to chronic spondyloarthritis of varying activity 1
• Most cases do not result in long-term joint deformity 3
• Without proper management, reactive arthritis can progress to chronic destructive arthritis 4

Critical Pitfalls to Avoid

• Do not dismiss migratory arthritis as simple reactive arthritis without ruling out acute rheumatic fever, as missing ARF can lead to life-threatening valvular disease 7
• Do not use antibiotics for enteric reactive arthritis, as they provide no benefit 8, 9
• Do not use HLA-B27 as a diagnostic criterion for acute reactive arthritis 2
• Do not delay cardiac evaluation in poststreptococcal cases, as subclinical carditis may be missed 7