What is the best management approach for a pediatric patient with ankle and knee pain, limited range of motion, and warmth, who had gastroenteritis (inflammatory bowel disease) 2 weeks ago, with normal blood results and no effusion on X-ray?

Management of Pediatric Reactive Arthritis

This pediatric patient with post-infectious arthritis following gastroenteritis should be treated with oral ibuprofen (Option A) as first-line therapy, as this presentation is most consistent with reactive arthritis, which does not require antibiotics or invasive procedures.

Clinical Reasoning

Why This is Reactive Arthritis, Not Septic Arthritis

• Normal blood results (including normal white cell count and inflammatory markers) effectively exclude septic arthritis, which would typically show elevated WBC and CRP 1
• No effusion on X-ray further argues against septic arthritis, which characteristically presents with joint effusion 2
• Two-week interval following gastroenteritis is the classic timing for reactive arthritis development 1
• Multiple joint involvement (ankle and knee) with inflammatory signs is typical of reactive arthritis rather than bacterial infection 1

Why Oral Ibuprofen is the Correct Choice

• NSAIDs are first-line therapy for reactive arthritis with inflammatory joint involvement, demonstrating an effect size median of 0.49 in inflammatory joint conditions 1
• Ibuprofen 2400 mg/day (weight-adjusted for pediatrics: typically 30-40 mg/kg/day divided into 3-4 doses, maximum 2400 mg/day) has comparable efficacy to other NSAIDs in inflammatory arthritis 1
• NSAIDs should be started immediately in clinically non-septic presentations without waiting for joint aspiration 1

Why Other Options Are Incorrect

• Oral aspirin (Option B) is not recommended as first-line in pediatric patients due to risk of Reye's syndrome, particularly following viral gastroenteritis 1
• Synovial aspiration (Option C) is unnecessary when clinical presentation clearly indicates reactive arthritis with normal blood work and no effusion 1
• IV antibiotics (Option D) are contraindicated as this is post-infectious reactive arthritis, not active septic arthritis; normal blood results exclude bacterial infection 1

Treatment Algorithm

Immediate Management

• Start oral ibuprofen 400-800 mg three times daily (or 30-40 mg/kg/day divided TID-QID for pediatric dosing, max 2400 mg/day) 1
• Assess GI risk before initiating NSAIDs; consider gastroprotection with proton pump inhibitor if risk factors present 1
• Provide patient/family education about reactive arthritis, expected self-limited course (typically 3-6 months), and importance of medication adherence 1

Adjunctive Non-Pharmacological Measures

• Relative rest of affected joints initially during acute inflammation 1
• Quadriceps strengthening exercises once acute inflammation subsides 1
• Weight-bearing as tolerated to maintain function 2

Follow-up and Reassessment

• Reassess in 1-2 weeks to evaluate treatment response 1
• If inadequate response, consider intra-articular corticosteroid injection if significant effusion develops 1
• Monitor for NSAID complications including gastrointestinal bleeding, renal dysfunction, and cardiovascular effects 1

Critical Pitfalls to Avoid

• Do not delay NSAID treatment waiting for joint aspiration in a clinically non-septic presentation with normal blood work 1
• Do not use aspirin in pediatric patients, especially following viral gastroenteritis, due to Reye's syndrome risk 1
• Do not prescribe antibiotics for reactive arthritis, as this is a post-infectious inflammatory condition, not an active infection 1
• Do not perform unnecessary invasive procedures (joint aspiration) when clinical presentation and normal labs clearly indicate reactive arthritis 1

Expected Clinical Course

• Symptoms typically improve within 1-2 weeks of NSAID therapy 1
• Complete resolution usually occurs within 3-6 months, though some cases may persist longer 1
• Recurrence is uncommon but patients should be counseled about potential for symptom return 1