Occupational vibration syndrome

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Occupational vibration syndrome

• Department of Occupational Medicine
• Finnish Institute of Occupational Health

Markku Sainio Markku Vanhanen
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Definitions

• Vibration
• Hand-arm vibration (HAV)
• Whole-body vibration (WBV)
• Vibration white finger (VWF)
• Hand-arm vibration syndrome (HAVS)
• Raynaud's phenomenon
• Electroneuromyograpy (ENMG)

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Vibration

• Periodic motion of a body in alternate opposite
  directions from a position of rest
• Mathematical "vector quantity" described by both
  a direction and a magnitude
• directions of vibration
• acceleration
• Present in most work settings where mechanical
  equipment is used

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Measurements and standards

• ACGIH TLVs 1984
• 4 m/s2 lt 8 hours a day
• 6 m/s2 lt 6 hours a day
• 8 m/s2 lt 2 hours a day
• 12 m/s2 lt 1 hour a day
• ISO 5349 (1986)
• Standard for measurements over frequencies from 5
  to 1500 Hz
• Mitä laatua käytetään, millaiset tasot aih
  tautia, impact vibration (high impulsiveness)
  important!

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Dose-response curves and threshold limits

• are not applicable to all tools
• are derived from chain-saw data
• do not take into account impulsiveness and high
  frequency of many tools

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Directive 2002/44/EC

• .. on the minimum health and safety requirements
  regarding the exposure of workers to the risks
  arising from physical agents (vibration)...
• daily (8 h) exp. limit value 5 m/s2
• daily exp. action limit value 2,5 m/s2

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HAV as occupational disease in Finland 1990-2001

• ROD FIOH
• 2001-4/2002 10
• 1999-2000 32 16
• 1997-98 38 17
• 1995-96 37 7
• 1993-94 44 18
• 1990-92 (3 yrs) 92 37

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Occupations (FIOH 1990-2001)

• Chain saw work 22
• Construction worker 15
• Miners drillers 15
• Machine work,-repair, tool makers 9
• Welders 5

• Pipework 4
• Railroad or road work 3
• Stonework 3
• 1-2 dental technician, teacher, painter,
  manufacture of diff. devices, plastics worker
  etc.

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Exposure

• Vibration level, acceleration, frequency, angles,
  impulses
• Duration, continuity, radiation of the vibration
  (tool weight, grip strength, hand position,
  exposure area)
• Smoking increases VWF prevalence, if gt 20
  cigarettes/d gt 20 years
• Temperature

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Hand-arm vibration syndrome (HAVS)

• Disease entity with separate components, all of
  which may not be recognized at the same time
• Circulatory disturbances
• secondary Raynaud vasospasm with local finger
  blanching
• Sensory and secondary motor disturbances
• local polyneuropathy numbness, clumsiness
• Musculoskeletal disturbances (?)
• HAVS may lead to severe disease causing permanent
  working disability

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Hand-arm vibration syndrome (HAVS)

• White finger symptoms are essential
• however, not always present
• Dose-related (quantity and quality of exposure)
• May be reversible, but usually irreversible and
  progressive if exposure continues
• Smoking and cold exposure predisposing risk
  factors
• Individual differences in susceptibility (other
  causes of Raynaud???)

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Symptoms

• Cold/damp (sometimes vibration) induced white
  fingers
• However, also peripheral sensory reduction and
  slight clumsiness without white fingers
• More proximal bone and joint symptoms occur
  occasionally (may be due to ergonomic factors)
• Carpal tunnel syndrome and epicondylitis coexist
  often

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PATOPHYSIOLOGY

• Local oedema in nerve and perineural tissue
• Local damage in non-myelinated nerve fibers ?
  changes in blood vessels ?vasoconstriction in
  cold
• mechanism adrenergic reseptor damage in vessel
  walls?alfa-2-reseptor predominance

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Objective findings

• Vibration detection levels increase (damaged
  thick myelin fibers)
• Temperature detection levels increase (damaged
  thin myelin fibers)
• Two-point differentiation ability reduced
• Grip strength reduced
• Finger pletysmography blood pressure of the
  affected finger drops in cold exposure
• ENMG sensory conduction velocities reduced
  before motor velocities

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Diagnosis I

• Exposure sufficient
• Exp. in Occupational medneurologyfysiatry
• Clinical status Sensory testing, grip strength,
  fine motor testing
• Finger pletysmography (sensitive, not all mild
  cases detected, replicability ok)
• Lab La, CRP, PVK, tromb, CDT, GT, TSH,
  kryoglobulins, RF, nucleus-ab, B-gluc,
  Pt-Gluc-R1, S-B12-vit, fE-folaat

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Diagnosis II

• ENMG, possible carpal tunnel syndrome and
  excludes other PNS disease
• Vibration and cold/hot perception threshold
• Neurologist PNP exclusion
• Fysiatrist exclusion of TOS or over
  extremity/cervical disease
• Angiography not rutinely used

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VWF clinical problems"

• No white finger findings, only sensory findings
• White finger findings, but also
• generalized polyneuropathy
• cervical radiculopathy
• blood vessel changes mimicing vasculitis
• Primary Raynauds disease in the history or
  symptoms/findings suggesting it (prevalence 5-6
  in males)
• Occupational rehabilitation is often difficult
  (progressed HAVS or wide accompanied
  musculoskeletal symptoms)

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Whole body vibration

• May increase the rsik of low back pain, disc
  protrusion and joint arthritis
• May increase the risk of spontaneous abortions
  and premature births
• Difficult to diagnose at indivudual level
• Directive 2002/44/EC
• 8 hour limit 1,15 m/s2
• 8 hour action limit 0,5 m/s2

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Treatment and prevention

• Calcium antagonists may help
• Carpal tunnel operation may help, but may also
  worsen symptoms
• Stop smoking, reduce risk factors of
  polyneuropathy
• Stop or decrease exposure to minimum
• technical improvements of tools
• minimum exposure time
• gloves etc.
• Increase temperature
• Periodic health examinations

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Literature

• Hannu Vironkannas Peripheral vascular and nerve
  disorders in workers exposed to hand-arm
  vibration with special reference to snowmobile
  drivers, 1992. (Thesis)
• Pelmear PL, Leong D. Review of occupational
  standards and guidelines for hand-arm (segmental)
  vibration syndrome (HAVS). Applied Occupational
  and Environmental Hygiene. Vol 15(3)291-302,
  2000.