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What is your diagnosis?

Pyogenic flexor tenosynovitis. Pyogenic or suppurative flexor tenosynovitis (PFT) is when there is a severe bacterial infection within the closed space of the digital flexor tendon sheaths [1]. Because of the closed space, the infection can lead to necrosis of the tendons and ultimately devitalization of the fingers [2]. 

How does this injury present? What are some of the key exam findings?

Pyogenic flexor tenosynovitis is found in about 2.5% to 9.5% of all hand infections [3]. This injury usually presents after a recent penetrating hand injury. Although there is no difference in PFT incidence rates between gender and age, certain medical conditions can cause patients to be at higher risk for this condition. These include but are not limited to patients with reduced immunity (eg, malnutrition, chronic steroid use, autoimmune disease, peripheral vascular disease, and diabetes mellitus) because they are at higher risk of PFT and its complications [4].

• Pearl: The key exam findings are: flexor sheath tenderness, flexed position of the affected digit, painful passive digital extension, and fusiform swelling of the digit [5].

• These key examination findings noted above are referred to as the Four Kanavel signs in practice [5]. When using all four Kanavel signs on a physical exam, a study showed a sensitivity range of 91.4% to 97.1% and a specificity range of 51.3 to 69.2% [6]. 

How is it diagnosed?

PFT is diagnosed clinically, based on history and physical exam findings (Kanavel signs as above). When inconclusive, labs and imaging can be ordered to evaluate for other pathologies [7]. 

• Labs: CBC, ESR, CRP, with consideration of blood and wound cultures if able or concern of sepsis present (PFT typically involves leukocytosis and elevated inflammatory markers and can be used to monitor treatment response [8]). 

• Imaging: While not required, x-ray can be helpful to rule out foreign body and can identify soft tissue swelling. Ultrasonography is a helpful adjunct to evaluate the flexor tendons/tendon sheath and is often rapid and available at bedside. Example of ultrasonography for PFT seen in Image 2 [9].

Image 2: Image Courtesy of Maulik Patel, radiopaedia.org; rID: 48661. Ultrasound image longitudinal view showing increased anechoic edema and debris in the flexor tendon sheath consistent with diagnosis of flexor tenosynovitis.

What is your management in the ED? What is your disposition?

PFT is a surgical emergency and thus consultation with Orthopedic Surgery is warranted in the ED. Treatment includes open irrigation and debridement with broad spectrum IV antibiotic coverage for common skin flora (including staph (including MRSA) and strep as below) [10]. 

• Vancomycin 1gm IV q12hr AND any one of the following: 

• Ampicillin/Sulbactam 1.5gm IV q6h OR

• Cefoxitin 2gm IV q8h OR

• Piperacillin/Tazobactam 3.375gm IV q6h

• Pearl: For diabetic patients who need antipseudomonal coverage, recommend Vancomycin + Piperacillin/Tazobactam. If injured out at sea, consider adding a fluoroquinolone, tetracycline, or sulfamethoxazole/trimethoprim to cover common marine organisms such as the vibrio species [11].