At the Bedside
- Classic presentation: Usually after puncture wound, bite, splinter, IV drug use, or seemingly minor trauma.
- Kanavel signs:
- Fusiform swelling of the digit
- Digit held in slight flexion
- Tenderness along the flexor tendon sheath
- Pain with passive extension — often the earliest/highest-yield sign
- Exam priorities:
- Inspect for puncture wounds, bites, abscess, felon, paronychia, cellulitis.
- Assess active/passive ROM, neurovascular status, cap refill.
- Look for signs of deep-space hand infection or septic arthritis.
- Workup:
- Diagnosis is primarily clinical.
- X-ray hand/finger: Evaluate for foreign body, fracture, gas, osteomyelitis, retained tooth fragment if bite.
- Labs: CBC, BMP, ESR/CRP, blood cultures if febrile/systemically ill. Normal labs do not exclude.
- Ultrasound may show fluid around tendon sheath but should not delay hand consultation.
- Initial ED management:
- Immediate hand surgery/orthopedic/plastic surgery consult.
- Immobilize in position of function, elevate.
- NPO in anticipation of operative washout.
- Start empiric IV antibiotics covering Staph aureus including MRSA and Strep.
- Add gram-negative/anaerobic coverage for bites, immunocompromise, water exposure, IVDU, or severe infection.
- Tetanus update if indicated.
- Definitive therapy:
- Early cases may be trialed with IV antibiotics, elevation, and serial exams only under hand-surgery direction.
- Most require urgent operative irrigation/debridement, especially if delayed presentation, purulence, necrosis, severe pain, immunocompromise, or systemic toxicity.
- Disposition:
- Admit for IV antibiotics, serial hand exams, and likely operative management.
- Do not discharge suspected flexor tenosynovitis without hand-surgery agreement.
A Classic Presentation
A 34-year-old man presents with worsening right index finger pain 2 days after a puncture wound from a metal wire. The finger is diffusely swollen, held in flexion, exquisitely tender along the volar surface, and passive extension causes severe pain. X-ray shows no fracture or foreign body. You make the clinical diagnosis of pyogenic flexor tenosynovitis, update tetanus, start IV vancomycin plus ampicillin-sulbactam, elevate and splint the hand, keep him NPO, and call hand surgery for urgent operative evaluation.
Study Directive
- Memorize and recite the 4 Kanavel signs without notes.
- Review your institution’s empiric hand-infection antibiotic pathway, especially MRSA and bite coverage.
- Practice a focused hand exam: inspect, vascular, sensory, motor, tendon function, passive ROM, and pain localization.
- Look at 3 clinical images of flexor tenosynovitis and distinguish it from felon, paronychia, cellulitis, and septic arthritis.
- Create a one-line ED disposition rule: “suspected flexor tenosynovitis = NPO + IV antibiotics + hand consult + admit.”
Recent Literature
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Review or guideline High risk and low prevalence diseases: Flexor tenosynovitis
EM-focused review of a high-risk hand infection, reinforcing early recognition with Kanavel signs, prompt IV antibiotics, urgent hand-surgery consultation, and the pitfalls of delayed diagnosis.
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Recent clinical Antibiotics Versus Surgery in Treatment of Early Flexor Tenosynovitis
Recent clinical study addressing whether carefully selected early presentations may improve with antibiotics alone, while underscoring that most suspected cases still need urgent specialist evaluation and close reassessment.