Vibration white finger – hand arm vibration syndrome
What is vibration white finger?
Vibration white finger, also known as hand-arm vibration syndrome, is one of the causes of Raynaud phenomenon. The syndrome affects the blood vessels, nerves, muscles, joints and connective tissue of the hand, wrist and arm. It is not uncommon, with many developed countries publishing regulatory documentation on frequency (Hz) exposure limits, effects and control.
Who is affected by vibration white finger?
Workers who use hand-held or hand-guided power tools for more than a few hours each day are at risk of vibration white finger. The period of time between exposure to vibration and development of symptoms is variable, ranging from months to years. The risk of developing hand-arm vibration syndrome increases with the intensity and duration of exposure to vibration, and continued exposure results in worsening symptoms. It is recommended that individuals that suffer from certain vascular or neurological disorders affecting the hand or arm, e.g. Raynaud disease or carpal tunnel syndrome, are not exposed to vibration at work.
What causes vibration white finger?
Vibration white finger may occur in those using handheld vibrating tools such as sanding tools, hammer drills, jackhammers and chain saws. It may also be caused by holding or working with machinery that vibrates. Vibration promotes vasoconstriction through arterial smooth muscle hypertrophy, and damage to the endothelial cell walls; there is an increase in the release of vasoconstricting chemicals such as serotonin and thromboxane. Nerve damage also occurs.
Clinical features of vibration white finger
There are some specific features and symptoms of vibration white finger:
- Symptoms of nerve damage include pain, tingling, numbness, and reduced dexterity. Initially symptoms are intermittent, but they may become continuous if exposure to vibration continues.
- Vascular manifestations include the cold-induced vasoconstriction (vasospasm) causing the fingertip or finger to turn white due to lack of blood supply. One or more fingers may be affected.
- The fingers may turn blue in more advanced cases when all the available oxygen in the blood is used up.
- When rewarming, the fingers turn bright red.
- Attacks can occur after using vibrating tools, especially if the hands are exposed to cold.
- Musculoskeletal complications include reduced grip strength, osteoporosis of the wrist or elbow, and bone cysts.
What can be done to improve the vibration white finger?
- Keep hands as warm as possible, to stop spasms in the arteries of the fingers and to improve circulation.
- Smokers should cut down or quit, as tobacco causes the blood vessels to constrict, decreasing the blood flow to the fingertips.
- Take regular exercise to improve circulation.
- Avoid tight clothing that may restrict the blood flow.
- Try to avoid sitting for long periods of time – regular exercise, such as walking around a room, moving arms and legs to maintain circulation, will help make sure that fingers and toes do not get cold.
- Try to keep warm. If clothing gets wet, change it immediately. Drink hot drinks.
- Avoid touching cold objects.
Work place advice:
- Limit the use of vibrating tools. If practical, avoid them completely.
- See if its possible to replace the vibrating tool with an alternative method of getting the job done efficiently.
- Hold vibrating tools as loosely as possible and in varying positions.
- Ensure tools are well maintained; make sure cutting blades are kept sharp to maintain efficiency, and replace worn parts.
- Use tools correctly, and use the right tool for the job (to do the job more quickly and reduce exposure time).
- Store tools so that they do not have very cold handles when next used.
- Use anti-vibration gloves.
- Take regular breaks of at least 10 minutes every hour away from the tool.
- Choose low vibration brands/models of equipment.
Standard tests used to diagnose vibration white finger include:
- Vibrotactile threshold test: to measure the sensitivity of the mechanoreceptors in the nerves of each hand to stretch, texture and vibration.
- Thermal aesthesiometry test: to measure the thermal receptors (for cold/heat).
- Purdue pegboard test: to measure dexterity and any loss of movement in either hand.
- Cold provocation test: provides visual evidence of blanching.
It is appropriate to rule out Raynaud’s disease, or secondary Raynaud’s phenomenon due to other causes.
Treatment of vibration white finger
If a worker has developed vibration white finger, management may include:
- Reducing or ceasing exposure to vibrating tools. However, in more advanced cases symptoms may be persistent after cessation of exposure.
- Encouragement to give up smoking
- Referral to a dermatologist, rheumatologist or neurologist for assessment and treatment, including calcium channel antagonists, and pain management.