Description of peripheral nervous system involvement in wild-type transthyretin amyloidosis: A clinical and electrophysiological study.

Abstract

Introduction: Wild-type transthyretin amyloidosis (ATTRwt) is not clearly known to be associated with peripheral neurological complications. The aim of our study was to characterize neurological involvement in ATTRwt, as well as its evolution over time, using clinical and electrodiagnostic (EDX) data.

Methods: We prospectively included patients diagnosed with ATTRwt who were addressed by cardiologists. All patients underwent neurological evaluation, including examination (neuropathy impairment score) and an EDX study including electrochemical skin conductance and/or sympathetic skin response testing. Motor, sensory, and small fiber composite sum scores were calculated based on the EDX data. Clinical and EDX scores were then reassessed during the follow-up period.

Results: Fifty-two patients were included, 94% of whom were treated with tafamidis. At inclusion 98% of patients presented peripheral nerve involvement at EDX, the most common being carpal tunnel syndrome (88%), polyneuropathy (67%), and ulnar tunnel syndrome (21%). Twenty-nine patients were reevaluated and mean follow-up was 16.7months with no significant change of clinical or neurophysiological data.

Discussion: In our cohort, a large majority of ATTRwt patients showed peripheral nerve involvement, generally expressed as the combination of different neurological syndromes (entrapment syndromes, large and/or small fiber polyneuropathy, radicular impairment). Polyneuropathy in ATTRwt seemed stable over our follow-up period. Clinical and EDX screening should be conducted in ATTRwt patients with symptoms suggestive of neurological involvement in order not to oversee these frequent complications which could affect therapeutic decision making.