What are the recommended antibiotics for treating Lyme joint effusion?

Antibiotic Treatment for Lyme Joint Effusion

For Lyme arthritis with joint effusion, oral doxycycline (100 mg twice daily), amoxicillin (500 mg three times daily), or cefuroxime axetil (500 mg twice daily) for 28 days is the recommended first-line treatment. 1

First-Line Oral Antibiotic Options

Adults:

• Doxycycline: 100 mg twice daily for 28 days
• Amoxicillin: 500 mg three times daily for 28 days
• Cefuroxime axetil: 500 mg twice daily for 28 days

Children:

• Amoxicillin: 50 mg/kg/day in 3 divided doses (maximum 500 mg per dose) for 28 days 1
• Cefuroxime axetil: 30 mg/kg/day in 2 divided doses (maximum 500 mg per dose) for 28 days 1
• Doxycycline (if ≥8 years old): 4 mg/kg/day in 2 divided doses (maximum 100 mg per dose) for 28 days 1, 2

Treatment Algorithm for Lyme Joint Effusion

1. Initial treatment: 28-day course of oral antibiotics as listed above 1

2. Partial response (mild residual joint swelling after first course):

   • Consider a second 28-day course of oral antibiotics, especially if synovial proliferation is modest compared to joint swelling 1
   • Monitor for resolution

3. Minimal or no response (moderate to severe persistent joint swelling):

   • Switch to intravenous ceftriaxone (2 g once daily) for 2-4 weeks 1
   • Alternative IV options: cefotaxime (2 g IV every 8 hours) or penicillin G (18-24 million units/day IV divided every 4 hours) 1

4. Persistent arthritis despite IV therapy (antibiotic-refractory):

   • Refer to rheumatologist for consideration of:
     • NSAIDs
     • Disease-modifying antirheumatic drugs
     • Intra-articular corticosteroids (only after completion of antibiotic therapy and negative PCR for B. burgdorferi) 3
     • Arthroscopic synovectomy for cases with significant pain or limited function 1

Important Clinical Considerations

• Macrolide antibiotics (azithromycin, clarithromycin, erythromycin) should not be used as first-line therapy due to lower efficacy 1
• First-generation cephalosporins, fluoroquinolones, and many other antibiotics are ineffective and should not be used 1
• Joint aspiration may be necessary for diagnosis (sending synovial fluid for PCR testing) and symptom relief 4
• Do not administer intra-articular steroids before or during antibiotic treatment as this may worsen outcomes 3
• Lyme arthritis typically affects large joints, particularly the knee, and may be monoarticular or oligoarticular 5
• Pregnant patients should receive the same treatment except doxycycline should be avoided 1

Treatment Pitfalls to Avoid

1. Prolonged antibiotic therapy: Treatment beyond the recommended durations does not improve outcomes and increases risk of adverse effects 1

2. Premature use of corticosteroids: Intra-articular steroids should only be used after adequate antibiotic therapy and negative PCR for B. burgdorferi 3

3. Misdiagnosis: Ensure proper diagnosis through serology and, when needed, PCR of synovial fluid 1

4. Inadequate follow-up: Some patients may require multiple courses of therapy or transition to IV antibiotics if oral treatment fails 1

5. Confusing persistent symptoms with active infection: Persistent symptoms after adequate antibiotic therapy may represent post-Lyme disease syndrome rather than active infection requiring further antibiotics 1