What is the appropriate management for a patient with joint pains following a diarrheal illness, considering their recent gastrointestinal infection and potential for reactive arthritis?

Management of Post-Diarrheal Joint Pain (Reactive Arthritis)

For a patient presenting with joint pain following diarrheal illness, initiate treatment with NSAIDs (or intra-articular corticosteroid injection for large joint oligoarthritis) while confirming the diagnosis through stool culture, inflammatory markers, and joint aspiration to exclude septic arthritis, then escalate to sulfasalazine or methotrexate if symptoms persist beyond 4 weeks. 1

Initial Diagnostic Workup

The diagnosis of reactive arthritis is primarily clinical, based on acute oligoarticular arthritis of larger joints developing within 2-4 weeks of preceding gastrointestinal infection 2. Critical diagnostic steps include:

• Obtain stool culture to identify triggering organisms (Salmonella, Shigella, Yersinia, Campylobacter, or Clostridium difficile) 1, 3
• Perform joint aspiration if effusion present to exclude septic arthritis and crystal-induced arthropathy - expect sterile fluid with predominant neutrophils 4, 1
• Check inflammatory markers (ESR, CRP), autoimmune panel (ANA, RF, anti-CCP) if symptoms persist 1
• Consider HLA-B27 testing only if symptoms suggest axial involvement or reactive arthritis affecting the spine - do NOT use as a diagnostic tool for acute reactive arthritis 1, 2

Common pitfall: Gastrointestinal infections with Salmonella, Shigella, Yersinia, and Campylobacter may be followed by reactive arthritis, and the interval between gastrointestinal and arthritic symptoms can complicate recognition 1, 3

First-Line Treatment Strategy

For Mild-to-Moderate Symptoms (Grade 1-2)

• Start NSAIDs at high doses as initial therapy - these are more effective than simple analgesia for reactive arthritis 1, 5
• For oligoarthritis (≤4 joints): Consider intra-articular corticosteroid injection for large joints, which provides rapid relief without systemic exposure 1
• Continue ICPi/monitor for 4 weeks before escalating therapy 1

For Moderate-to-Severe Symptoms (Grade 2-3)

• Initiate oral prednisone 10-20 mg/day for rapid symptom control 1
• Short-term systemic glucocorticoids should be used as bridge therapy only, with planned taper over 4-6 weeks 1, 6
• Avoid long-term corticosteroids - these are adjunctive only and should be discontinued once disease-modifying therapy takes effect 1, 6

Disease-Modifying Therapy

When to Escalate (After 4 Weeks of Initial Treatment)

If symptoms persist or inadequately controlled after initial 4-week trial of NSAIDs/corticosteroids 1:

For peripheral arthritis with mild disease:

• Sulfasalazine 2-3 g/day is the treatment of choice for mild peripheral reactive arthritis 1

For persistent or severe peripheral arthritis:

• Methotrexate can be considered for control of peripheral arthritis, particularly if sulfasalazine fails 1
• If unable to lower corticosteroid dose below 10 mg/day after 6-8 weeks, initiate DMARD therapy 1

For severe refractory disease (Grade 3-4):

• TNF inhibitors (infliximab, adalimumab, or golimumab) are recommended as first-line advanced therapy for moderate-to-severe disease or failure of conventional DMARDs 1
• Consider synthetic DMARDs (methotrexate, leflunomide, hydroxychloroquine, sulfasalazine) alone or in combination before biologics 1

Antibiotic Considerations

Critical distinction based on causative organism:

• For Chlamydia-induced reactive arthritis: Prolonged treatment with doxycycline may be beneficial and can shorten the course or abort onset of arthritis 2, 5
• For enteric pathogens (Salmonella, Shigella, Yersinia, Campylobacter): Antibiotics have NOT been shown to shorten the duration of acute arthritis and are not recommended for reactive arthritis itself 2, 5
• Exception: Severely ill or immunocompromised patients with active enteric infection should receive systemic antibiotic treatment for the infection itself 1

Monitoring and Follow-Up

• Assess disease activity every 4-6 weeks after treatment initiation with serial rheumatologic examinations and inflammatory markers 1
• If no improvement after 4 weeks of initial therapy, treat as Grade 3 and escalate to DMARDs 1
• Refer to rheumatology if joint swelling (synovitis) persists, if symptoms don't respond to initial treatment, or for severe disease requiring biologic therapy 1

Long-Term Prognosis Considerations

Symptoms may persist for long periods and can cause long-term disability in some cases 5. Reactive arthritis following enteric infection has variable outcomes, with some patients developing chronic arthritis or spondyloarthropathy 7, 2. Early recognition and appropriate treatment are critical to prevent erosive joint damage 1.