What is the best management approach for a 3-year-old (three-year-old) child presenting with migratory arthritis, initially affecting the left knee and then the right knee, after a suspected streptococcal (Streptococcus) infection?

Management of Migratory Arthritis in a 3-Year-Old Following Suspected Streptococcal Infection

This child has acute rheumatic fever (ARF) until proven otherwise, and you must immediately start penicillin prophylaxis (Option A: Penicillin for 10 days to eradicate residual streptococcal infection, followed by continuous secondary prophylaxis) while urgently evaluating for carditis. 1, 2

Immediate Diagnostic Actions

The migratory pattern of arthritis—initially affecting the left knee with inability to bear weight, then shifting to the right knee while the left improves—is the hallmark presentation of ARF occurring 14-21 days after streptococcal pharyngitis. 2, 3 This clinical picture distinguishes ARF from post-streptococcal reactive arthritis (PSRA), which typically presents with cumulative, persistent arthritis rather than migratory symptoms. 4

You must perform urgent cardiac evaluation with both clinical examination and echocardiography, as cardiac involvement determines both prognosis and the duration of prophylaxis, and subclinical carditis can be missed on clinical examination alone. 2

Treatment Protocol

Initial Antibiotic Course

Start with a full 10-day therapeutic course of penicillin to eradicate any residual group A streptococcal infection, even if throat culture is currently negative. 1 This addresses Option A directly.

Penicillin V 250 mg orally twice daily is the first-line treatment. 2 For penicillin-allergic patients, use sulfadiazine 0.5-1 g daily or a macrolide (erythromycin or clarithromycin) or azithromycin. 2

Secondary Prophylaxis Duration

After the initial 10-day course, transition to continuous long-term prophylaxis (not monthly as suggested in Option C, which is incorrect). 1

• If no carditis detected: Continue prophylaxis for 5 years or until age 21, whichever is longer. 1, 2
• If carditis without residual valvular disease: Continue for 10 years or until age 21, whichever is longer. 1
• If carditis with valvular disease: Continue for 10 years or until age 40, whichever is longer, and consider lifelong prophylaxis. 1, 2

Symptomatic Management with Aspirin

Aspirin (Option D) should be used for symptomatic relief of arthritis and serves as a diagnostic test, with dramatic response within 24-48 hours supporting the ARF diagnosis. 2 However, aspirin is adjunctive therapy, not the primary treatment—penicillin prophylaxis is essential to prevent recurrent streptococcal infections and subsequent cardiac damage. 2

Why Other Options Are Incorrect

Option B (Streptococcus vaccine): No streptococcal vaccine exists for clinical use. This is not a valid treatment option. 1

Option C (Monthly prophylaxis): While benzathine penicillin G can be given intramuscularly every 3-4 weeks for secondary prophylaxis, the question context suggests monthly dosing as the primary intervention, which misses the critical initial 10-day eradication course. 1, 5

Option D (Aspirin alone): While aspirin provides symptomatic relief and diagnostic confirmation, it does not prevent the most serious complication—progressive valvular heart disease from recurrent streptococcal infections. 2

Critical Monitoring Strategy

Observe this child carefully for several months for clinical evidence of carditis, including serial cardiac examinations, repeat echocardiography, and monitoring for new murmurs, pericardial friction rubs, or signs of heart failure. 2 Even patients initially without carditis can develop valvular disease with subsequent streptococcal infections if prophylaxis is not maintained. 6, 7

Common Pitfalls to Avoid

Do not dismiss this as simple reactive arthritis. The migratory pattern strongly suggests ARF, and missing this diagnosis leads to failure to prevent life-threatening valvular disease. 2 Studies show that 8-17% of children with post-streptococcal reactive arthritis who do not receive prophylaxis subsequently develop carditis with future streptococcal infections. 6, 7

Do not delay cardiac evaluation. Subclinical carditis determines the entire prophylaxis strategy and long-term prognosis. 2

Do not stop prophylaxis prematurely. Patients with previous ARF are at very high risk for recurrence after subsequent group A streptococcal pharyngitis, and recurrences cause progressively worse cardiac damage. 1