Pyogenic Flexor Tenosynovitis
The infection of the flexor tendon sheath is called pyogenic flexor tenosynovitis (PFT), also known as septic or suppurative flexor tenosynovitis 1, 2, 3.
What You Need to Know
PFT is a rapidly progressing, closed-space infection of the flexor tendon sheath synovial fluid that represents 2.5-9.4% of all hand infections 2, 3. This is a surgical emergency that requires urgent recognition and treatment to prevent devastating complications including:
- Tendon rupture and necrosis
- Digital stiffness and loss of composite flexion
- Digit necrosis
- Amputation
- Sepsis 1, 2, 3, 4
Clinical Recognition
Look for Kanavel's four cardinal signs:
- Fusiform swelling of the affected digit
- Flexed posture of the finger at rest
- Tenderness along the flexor tendon sheath
- Pain with passive extension of the digit 5, 4, 6
Important Caveats
In young children and infants, Kanavel's signs are often incomplete or variable, making diagnosis challenging 5. Communication difficulties in pediatric patients can further delay recognition. When clinical presentation is equivocal, ultrasound can identify fluid collection within the flexor tendon sheath and confirm the diagnosis 5.
Pathophysiology
Bacterial seeding most commonly occurs from penetrating trauma overlying the sheath, followed by swift proximal propagation through the closed tendon sheath space 1, 3. The infection can occur from seemingly minor trauma—even a fingerstick glucose test has been reported as a source 1.
Treatment Urgency
Despite prompt treatment, complication rates as high as 38% have been reported 3. Even with successful infection eradication, patients frequently experience continuing pain, swelling, stiffness, weakness, and loss of function 3, 4. Patients with medical comorbidities or delayed presentation have significantly poorer outcomes, including severe digital stiffness or amputation 4.
The key to minimizing morbidity is immediate recognition and urgent surgical intervention combined with intravenous antibiotics—this is not a condition where conservative management is appropriate 3, 4.