Nerve Ultrasound Findings before and after Surgery in a Patient with Charcot-Marie-Tooth Disease Type 1A and Comorbid Carpal Tunnel Syndrome

Abstract

The diagnosis of comorbid carpal tunnel syndrome (CTS) in patients with Charcot-Marie-Tooth (CMT) disease is challenging due to the overlapping symptoms and inconclusive electrodiagnostic studies (EDX). This case report is aimed at illustrating the value of ultrasonography (US) in a patient with CMT1 disease and comorbid CTS. A 28-year-old woman presented with symptoms of painful paresthesia and weakness of both hands. EDX demonstrated a demyelinating sensory-motor polyneuropathy in the upper and lower extremities, consistent with CMT1 disease. US showed an increased cross-sectional area (CSA) of the median nerve at the carpal tunnel inlet (CTI) with a significant drop in the diameter within the carpal tunnel, confirming concurrent CTS. Genetic testing confirmed PMP22 duplication consistent with CMT1A. Bilateral carpal tunnel releases were performed with partial symptom resolution within 3 weeks. Postoperative EDX demonstrated improved motor conduction across the wrist, but the sensory potentials continued to be unrecordable. US showed a significant reversal of the diameter-drop of the median nerve within the carpal tunnel and decrease in CSA at the CTI. US imaging is a valuable technique for identifying comorbid CTS in patients with CMT and directing appropriate treatment.