Syndrome de vibration main-bras

What is hand-arm vibration syndrome?

Hand-arm vibration syndrome (HAVS) causes symptoms in fingers, hands and arms, as a result of using vibrating tools. It used to be called vibration white finger. The name was changed to HAVS, as other symptoms may occur in addition to white fingers.

The number of cases of HAVS has significantly reduced over the last few decades as employers have become more aware of how to reduce the risks.

Causes of hand-arm vibration syndrome

HAVS is caused by repeated and frequent use of hand-held vibrating tools - for example:

• Power drills.

• Chainsaws.

• Pneumatic drills.

• Working with machinery that vibrates.

It is not clear how vibration causes the condition. It is probably due to slight but repeated injuries to the small nerves and blood vessels in the fingers. Over time these may gradually lose some of their function and cause symptoms.

Up to 1 in 10 people who work regularly with vibrating tools may develop HAVS.

Symptoms of hand-arm vibration syndrome

Initially nerves are affected leading to changes in sensation. Phénomène de Raynaud later develops which results from changes in the blood vessels and causes white fingers. These changes can also lead to muscular aches and pains.

Nerve symptoms

Loss of feeling (numbness) and/or having des picotements (tingling) in one or more fingers are usually the early features. It may be mild and just affect the tip of the finger(s) and may come and go.

In severe cases a permanent numbness may extend along affected fingers. This may cause clumsiness and difficulty in doing fine tasks. For example, it may become difficult to fasten buttons or to handle coins or nails etc.

In most people the severity of nerve symptoms is between these two extremes. Sometimes one finger is badly affected with other fingers only mildly affected.

Raynaud's phenomenon - white finger symptoms

Raynaud's phenomenon comes in attacks that are triggered by a cold environment or touching a cold object. Raynaud's syndrome typically causes fingers to go white, then blue, then red.

Vibrating tools are just one cause of Raynaud's phenomenon. See the separate leaflet called Raynaud's phenomenon for other causes.

Douleurs et maux

Minor damage to the muscles, joints and bones may cause aches and pains in the hands and lower arm. The strength of grip may be weakened.

How do symptoms progress?

• In the early stages there may be some loss of feeling (numbness) or tingling (pins and needles) which comes and goes. This may be followed by bouts of Raynaud's phenomenon on cold days, affecting the ends of one or more fingers.

• Symptoms may remain mild but can progress if continuing to work with vibrating tools.

• As the condition develops, the numbness can become permanent. This leads to muscle weakness and wasting. Bouts of Raynaud's phenomenon tend to become more frequent and to occur in milder environments (eg, in summer if hands are wet).

• In some cases the symptoms develop months or years after finishing working with vibrating tools.

Diagnosing hand-arm vibration syndrome

The description of symptoms and the history of having worked for a long time with vibrating tools is often enough to clinch the diagnosis of HAVS. However, tests are sometimes needed and can be required for compensation claims. The tests may include checking grip strength, the ability to perform fine hand movements and the response of fingers to cold.

The Health and Safety Executive has a calculator that can help to gauge exposure to vibrations that can cause hand-arm vibration syndrome (see 'Further reading' section below).

Preventing hand-arm vibration syndrome

The following steps are thought to help prevent HAVS in workers who use vibrating tools:

• Holding tools as loosely as possible and in varying positions.

• Ensuring that tools are well maintained.

• Using tools correctly and using the right tool for the job. The aim is not to need to use excessive grip nor to use a tool for longer than necessary.

• Taking regular breaks of at least 10 minutes away from the tool. Short bursts of work are better than long periods of work without a break.

• Keeping warm while at work - especially your hands.

• Not smoking - the chemicals in tobacco can affect blood flow.

Quand consulter un médecin

Medical advice should be sought if suspecting HAVS. Concerns should also be reported to an employer, occupational health team (if there is one) and, where relevant, to a union representative. It is an employer's responsibility to ensure a safe and acceptable working environment.

Treatment for hand-arm vibration syndrome

Stop using vibrating tools if possible

This may prevent symptoms from getting worse. However, it is not clear whether nerve symptoms improve once they have developed.

Avoid medications that can make the circulation to the fingers worse

Voici quelques exemples :

• Bêta-bloquants, which are used for hypertension artérielle or heart problems.

• Décongestionnants that can be bought for cold and flu symptoms: these often contain adrenalin which can be bad for the circulation in hands.

• Certain migraine pills like propranolol, or those that are prescribed by specialists that contain medicines called ergot-derivates.

• In woman, sometimes the pilule contraceptive orale can make hand-arm vibration syndrome worse.

Arrêtez de fumer

• Smoking will cause narrowing of the arteries that pump blood to the fingers so stopping smoking is one of the most important factors in managing hand-arm vibration syndrome.

Médicaments

• Sometimes medications that relax the blood vessels can be tried but they do not always work. An example is nifedipine.

Employment and hand-arm vibration syndrome

Employers are aware of the risks of HAVS and this is usually disclosed to employees prior to starting work. Also listed below are other organisations which might be helpful:

• A trade union.

• The local Citizens Advice Bureau.

• The local Health and Safety Executive (HSE) area office.

• The Environmental Health Department of the local council.

• Department for Work and Pensions.

Outlook

HAVS does sometimes get better when use of vibrating tools is stopped early enough. However, where there are severe symptoms, it may persist, even after stopping.