EM@3AM – Flexor Tenosynovitis

Author: Erica Simon, DO, MHA (@E_M_Simon, EMS Fellow, SAUSHEC, USAF) // Edited by: Alex Koyfman, MD (@EMHighAK, EM Attending Physician, UTSW / Parkland Memorial Hospital) and Brit Long, MD (@long_brit, EM Attending Physician, SAUSHEC, USAF)

Welcome to EM@3AM, an emdocs series designed to foster your working knowledge by providing an expedited review of clinical basics. We’ll keep it short, while you keep that EM brain sharp.

A 56-year-old female, with a previous medical history of diabetes and HTN, presents to the ED for evaluation of a painful, swollen, finger. The patient reports removing a wood splinter from the volar aspect of her right index finger two days prior to arrival, but notes that since that time the digit has “exploded…it’s huge…it hurts, and it’s red…I can’t even move it.”

Triage VS: BP 135/86, HR 110, T 99.8 F oral, RR 14, SpO2 98% on room air.

Pertinent physical exam findings:
Right upper extremity: Radial and ulnar pulses palpable, bounding. Full ROM at the wrist. No TTP of the volar aspect of the hand. Median, radial, and ulnar nerve sensory function intact.
R index finger: fusiform digit, held in flexion, severe pain with passive extension, tenderness to palpation of the flexor tendon sheath; 0.5 cm linear eschar localized to the volar aspect of the digit, distal to the DIP.

What’s the next step in your evaluation and treatment?

Answer: Flexor Tenosynovitis1,2

  • Epidemiology: Frequently occurs following a penetrating injury. Commonly identified organisms: S. aureus and Streptococcus species.1 Significant morbidity: failure to treat => tendon vascular compromise and necrosis => loss of function.
  • Clinical Presentation: Patients often report incidental redness, pain, and swelling of a digit +/- the hand. Pain commonly worsens with range of motion.1
  • Evaluation and Treatment:1,2
    • Assess the ABCs and obtain VS.
    • Perform a thorough H&P:
      • Question specifically regarding recent trauma, factors pre-disposing to infection/poor wound healing (immunosuppression, diabetes, etc.), and tetanus status.
      • Physical examination:
        • Ensure the extremity is neurovascularly intact.
        • Pathognomonic findings => Kanavel’s signs:
          • Fusiform swelling of the digit
          • Digit held in flexion
          • Tenderness to palpation of the entire flexor tendon sheath
          • Disproportionate pain with passive extension
        • The thumb flexor tendon sheath is in continuity with the radial bursa of the palm, and the small-finger sheath communicates with the ulnar palmar bursa = potential formation of a horseshoe abscess => palpate the volar surface of the hand to elicit tenderness, induration, or fluctuance.1,2
      • Evaluation and Treatment:1,2
        • Flexor tenosynovitis is a clinical diagnosis: contact ortho (hand) => surgical emergency.
          • Immobilize and elevate the affected hand.
          • Initiate antibiotic therapy:
            • Ampicillin-sulbactam (1.5 g IV q 6 hrs), cefoxitin (2 g IV q 8 hr), or piperacillin-tazobactam (3.375 g IV q 6 hr) + vancomycin (1 g IV q 12 hr) if MRSA prevalence high.
          • Send spontaneous exudate for gram stain and culture.2
  • Pearls:
    • If identified within the first 24 hours of onset, flexor tenosynovitis may respond to heat, rest, elevation, and antibiotics, however, during this time period the majority of cases are mistaken for cellulitis, a paronychia, or a felon.1
    • In the sexually active patient, consider disseminated gonorrhoeae.1



  1. Bidic S, Schaub T. Infections of the Hand. In Plastic Surgery.3rd ed. Philadelphia, PA, Elsevier. 2013; 16:333-345.e2.
  2. Germann C. Nontraumatic Disorders of the Hand. In Tintinalli’s Emergency Medicine Manual. 8th ed. New York, NY. McGraw-Hill. 2018.


For Additional Reading:

EM Cases: Hand Emergencies:

EM Cases: Hand Emergencies

One thought on “EM@3AM – Flexor Tenosynovitis”

Leave a Reply

Your email address will not be published. Required fields are marked *