What are the next steps for a patient with a cat scratch injury 2 days prior to scheduled bunion surgery, now presenting with arm swelling?

Postpone Surgery and Treat Active Cat Scratch Infection

The bunion surgery must be postponed immediately, and the patient requires urgent evaluation and treatment for a likely cat scratch infection with ascending lymphangitis. 1, 2

Immediate Assessment

Clinical Evaluation

• Examine the arm for specific signs of infection: measure the extent of erythema and induration (>5 cm suggests invasive infection), assess for warmth, tenderness, purulent drainage, and red streaking indicating lymphangitis 3, 2
• Check vital signs: temperature ≥38.5°C or pulse ≥100 bpm indicates systemic involvement requiring more aggressive treatment 3
• Assess regional lymph nodes: palpate epitrochlear and axillary nodes for enlargement or tenderness, which typically appears 3 weeks after inoculation but can occur earlier 4, 5
• Look for a papule or pustule at the scratch sites, which develops 3-30 days after injury 4

Laboratory Testing

• Obtain Bartonella henselae serology with IgG titers (>1:256 is diagnostic for cat scratch disease) 4, 5
• Blood cultures if fever or systemic symptoms are present 2
• Consider wound culture if purulent drainage is present, though B. henselae is difficult to culture 5

Treatment Algorithm

For Mild Infection (Localized swelling, no systemic signs)

• Start amoxicillin-clavulanate 875 mg orally twice daily for 7-10 days as first-line therapy 1, 2
• This provides coverage against Pasteurella multocida (present in 75% of cat scratches) and other common pathogens 1, 2
• Alternative for penicillin allergy: doxycycline 100 mg twice daily 1, 2

For Moderate to Severe Infection (Lymphangitis, systemic symptoms)

• Initiate ampicillin-sulbactam 1.5-3.0 g IV every 6-8 hours if hospitalization is warranted 2
• Add azithromycin 500 mg on day 1, then 250 mg daily for 4 days if cat scratch disease with lymphadenopathy is confirmed or highly suspected 4, 1, 2
• Azithromycin has been shown to speed recovery in cat scratch disease 5

Adjunctive Measures

• Elevate the affected arm to reduce swelling and accelerate healing 1
• Thoroughly cleanse any open wounds with sterile normal saline 1, 2
• Update tetanus immunization if not current 1

Critical Pitfalls to Avoid

• Do NOT use first-generation cephalosporins (like cephalexin) as they have poor activity against P. multocida 2
• Do NOT proceed with elective surgery in the presence of active soft tissue infection, as this significantly increases risk of surgical site infection and systemic complications 3
• Do NOT assume this is simple cellulitis—cat scratches carry 10-20% infection risk with polymicrobial flora averaging 5 different organisms 1, 2

Surgical Postponement Rationale

Elective surgery must be delayed until the infection completely resolves because: 3

• Active soft tissue infection dramatically increases surgical site infection risk
• Systemic signs of infection (if present) contraindicate elective procedures
• The infection requires 7-10 days of treatment with clinical reassessment 1, 2

Follow-Up Plan

• Reassess in 48-72 hours to ensure antibiotic efficacy and clinical improvement 1
• Monitor for complications: septic arthritis, osteomyelitis, tendonitis (especially with hand/arm involvement), or disseminated cat scratch disease with hepatosplenic involvement 1, 2, 6
• Reschedule surgery only after: complete resolution of erythema, swelling, and systemic symptoms, typically requiring 2-4 weeks 4, 5
• Watch for late lymphadenopathy which can develop up to 3 weeks post-exposure and may persist 1-6 months 4, 5