Upper extremity neuromotor dysfunction caused by local vibration

Abstract

Vibration disease (VD) (pneumatic hammer disease) is a leader among occupational diseases. The prolonged use of vibrating tools is a high occupational health risk. The clinical picture of VD caused by local vibration includes sensorineural and upper extremity locomotor impairments that are polymorphic, polysyndromic, and not always specific. The International List of Occupational Diseases (2010) defines VD using the terms «vibration-induced white finger» (VWF) and «hand-arm vibration syndrome» (HAVS). VWF as a manifestation of secondary Raynaud’s syndrome is the most noticeable vascular injury in HAVS. According to the recommendations of the International Labor Organization (2011) and the order of the Ministry of Health of Russia (2012), the clinical manifestations of local vibration include upper extremity polyneuropathy, secondary Raynaud’s phenomenon, and carpal tunnel syndrome (CTS). The paper considers approaches to differentially diagnosing CTS and HAVS, primary and secondary Raynaud’s syndrome, as well as clinical, laboratory, and electrodiagnostic studies. Prolonged exposure to vibration may affect the large myelinated (Ab) fibers responsible for tactile touch, pressure, and vibration. Patients with VWF are frequently found to have hyperresponsiveness of the sympathetic nervous system, which affects digital vascular tone and appears as lower fingertip skin temperature. The paper discusses some possible mechanisms for the pathogenesis of vibration neuropathy (e.g. demyelination of peripheral nerve fiber), as well as the involvement of plasma endothelin-1 in vascular response to cold as one of the components of the pathogenesis of vascular disorders. The central nervous system (cortical reorganization, plasticity phenomenon) is believed to be implicated in the development and maintenance of vibration neuropathy.