Man with finger pain.

Abstract

An 18-year-old male presented to the emergency department with pain and swelling in the third digit of his left hand. Physical examination revealed a significantly swollen digit held in passive flexion (Figure 1). There was tenderness over the flexor sheath and severe pain with passive extension. Laboratory evaluation demonstrated a white blood cell (WBC) count of 7.81 103 μL, erythrocyte sedimentation rate (ESR) of 11 mm/g, and C-reactive protein (CRP) of 2.51 mg/dL. The emergency physicians performed point-of-care ultrasonography of the affected digit using a linear probe and a water bath (Figure 1). Given the ultrasound findings (Videos 1, 2), Hand Surgery was consulted, and the diagnosis was confirmed in the operating room. Soft tissue ultrasound using a water bath revealed anechoic fluid surrounding the flexor tendon (Figure 2). Purulence was noted within the flexor tendon sheath intra-operatively and cultures obtained grew Streptococcus agalactiae. The time-sensitive diagnosis of flexor tenosynovitis (FTS) relies heavily on history and physical examination, though additional laboratory studies and imaging is often necessary. Given the time-sensitive nature of the diagnosis of FTS, bedside ultrasound is an ideal modality to facilitate the diagnosis. On bedside ultrasound, early findings often consist of hypoechogenic peritendinous effusion with no signal on color Doppler and thickened synovial sheath.1 Using a water bath, as done in this case, allows for imaging without direct skin contact and allows high resolution imaging with minimal patient discomfort.2