vibration white finger ( VWF ) (hand-arm vibration syndrome)
Last reviewed 01/2018
Vibration-induced white finger (VWF) (hand-arm vibration syndrome) is secondary Raynaud's phenomenon caused by vibrating hand tools. This condition was intially described in 1911 by Loriga.
Pathogenesis:
- pathogenesis of white fingers appears to be a result of longterm exposure to various physical and psychological environmental stressors, but the relative importance of one stressor or other is unknown. Observations indicating a chronic autonomic disturbance include changes in cardiac functions, excessive hearing loss in persons with VWF, and reduced toe skin temperature also in the absence of acute cold or vibration exposure
- sympathetic hyperactivity is believed to be a major pathological factor for VWF - however damage to vaso-regulatory structures and functions in the finger skin are also involved. An abnormal level of sympathetic efferents is likely to be important for producing the symptoms in white fingers. Other findings, however, indicate that the pathogenesis also involves changes in alpha-adrenergic receptor mechanisms as well as endothelial damage.
- confounders such as cold exposure, smoking habits and variations in individual susceptibility are pathological factors
Symptoms of VWF include:
- paraesthesiae in the fingers which often continues after the machinery has been switched off
- often intially one fingertip temporarily turns white and may be painful - the finger turns white with increasing frequency
- other fingers become affected as the condition progresses -the thumb is not generally note affected
- there may be associated myalgia and arthralgia
Workers whose occupations place them at risk for developing VWF should have pre-employment physicals and thereafter should be regularly reviewed by clinicians who have knowledge about the diagnosis and treatment of VWF. Tests which can be used include plethysmography, arteriography, skin thermography, and sensory tests, such as two point discrimination depth sense, pinprick touch and temperature sensation. Other causes of Raynaud's phenomenon should be considered.