What is the treatment for infectious tenosynovitis?

Treatment of Infectious Tenosynovitis

Infectious tenosynovitis requires immediate empiric intravenous antibiotics directed at staphylococci and streptococci, combined with prompt surgical consultation for debridement and drainage, as delayed treatment leads to devastating complications including tendon necrosis, digital amputation, and permanent functional impairment. 1

Immediate Diagnostic Workup

Imaging

• MRI is the preferred imaging modality to establish the diagnosis and assess the extent of deep soft tissue involvement 1
• CT scan and ultrasound are acceptable alternatives when MRI is unavailable 1
• Repeat imaging should be performed if symptoms persist or bacteremia continues, to identify undrained infection foci 1

Laboratory Studies

• Obtain blood cultures and cultures of any purulent drainage before starting antibiotics 1
• Tissue biopsy provides the most sensitive specimen for culture, particularly when mycobacterial infection is suspected 2
• Expect elevated inflammatory markers (WBC, ESR, CRP) in pyogenic cases 3

Empiric Antibiotic Therapy

Standard Pyogenic Infections

For uncomplicated cases, start with:

• Oxacillin or nafcillin 2g IV every 6 hours, OR
• Cefazolin 0.5-1g IV every 8 hours 1

For severe or complicated infections requiring broader coverage:

• Vancomycin 15 mg/kg IV every 12 hours PLUS
• Piperacillin-tazobactam, ampicillin-sulbactam, OR a carbapenem 1

Bite-Related Infections

For animal or human bite-associated tenosynovitis:

• Amoxicillin-clavulanate covers both aerobic and anaerobic oral flora 2, 1
• Duration typically extends to 4 weeks for septic arthritis and 6 weeks for osteomyelitis 2

For cat bites specifically:

• Avoid first-generation cephalosporins, penicillinase-resistant penicillins, macrolides, and clindamycin due to high prevalence of anaerobes and Pasteurella multocida 1

Mycobacterial Tenosynovitis

When mycobacterial infection is suspected (chronic, indolent presentation):

For M. marinum, MAC, or M. terrae complex:

• Macrolide (clarithromycin or azithromycin) plus ethambutol based on susceptibility testing 2
• Ciprofloxacin and sulfonamides show good activity against M. terrae complex 2
• Linezolid is an alternative for M. terrae complex 2

For M. szulgai:

• Three to four-drug anti-tuberculosis regimen for 12 months beyond culture conversion 2
• Quinolones and newer macrolides show good in vitro activity 2

Surgical Management

Immediate surgical consultation is mandatory for aggressive infections with systemic toxicity 1

Surgical Principles

• Prompt surgical debridement and drainage prevent tendon necrosis and functional loss 2, 1
• Infected wounds should NOT be closed primarily 2
• Deep soft-tissue infections typically require urgent surgical drainage followed by vascular imaging and expeditious revascularization if PAD is present 2
• Half of mycobacterial tenosynovitis cases require extensive debridement, surgical intervention, or amputation despite medical therapy 2

Common Pitfall

Incision and drainage or fine needle aspiration WITHOUT complete surgical excision may lead to chronic fistula formation 2

Antibiotic Duration and Transition

• Start with IV antibiotics initially 1
• Transition to oral antibiotics once clinically improved 1
• Total duration: 2-3 weeks for uncomplicated pyogenic tenosynovitis 1
• Longer courses required for complications: 3-4 weeks for synovitis, 4-6 weeks for osteomyelitis 2

Adjunctive Measures

• Elevate the affected extremity to accelerate healing, especially if swollen 2
• Ensure tetanus prophylaxis is current (0.5 mL IM if outdated or unknown) 2
• Consider rabies prophylaxis for feral/wild animal bites in endemic areas 2

Critical Warning Signs

Foot infections in patients with peripheral artery disease (PAD) carry nearly 3-fold higher amputation risk when infection and PAD coexist 2. These patients require:

• Immediate interdisciplinary care team referral 2
• Vascular imaging and expeditious revascularization 2
• High index of suspicion, as diabetes with neuropathy may mask typical infection signs 2

Monitoring and Follow-up

• Monitor for clinical improvement and symptom resolution 1
• Outpatients should be reassessed within 24 hours by phone or office visit 2
• If infection progresses despite appropriate antimicrobial and surgical therapy, hospitalization is required 2
• Progressive inflammation despite treatment may necessitate amputation of the affected digit 3