Flexor Carpi Radialis Tenosynovitis Mimicking Carpal Tunnel Syndrome Diagnosed and Monitored with Ultrasound: Case Report

Abstract

The purpose of this report is to describe the value of ultrasound in diagnosing and monitoring flexor carpi radialis (FCR) tenosynovitis clinically mimicking carpal tunnel syndrome. A 62-year-old female had chronic right wrist pain with numbness and tingling in the first four digits. Physical examination suggested carpal tunnel syndrome. Ultrasound and power Doppler images demonstrated tenosynovitis of the FCR tendon, but a normal median nerve. Hyperemia was extending from the inflamed tendon to the adjacent median nerve, suggesting the FCR tenosynovitis was inducing a low-grade neuritis. Follow-up ultrasound at 3 weeks was performed due to worsening symptoms and demonstrated consistent tenosynovitis, prompting additional laboratory testing which excluded an inflammatory arthritis. More aggressive therapy was introduced at this time and repeat ultrasound 6 weeks later demonstrated near resolution of FCR tenosynovitis coinciding with symptom amelioration. This case underscores the value of ultrasound as an extension of the musculoskeletal examination to improve diagnostic specificity and guide appropriate care.