Occupational Disease Determination

1
Occupational Disease Determination
An Occupational Physicians Perspective
2
Dennis Stumpp, MD, MS

• Board certified, residency trained Occupational
  medicine
• Current Position
• Staff physician Valley Medical Center
  Occupational Health Services - Auburn 30
  hours/week
• IMEs and consulting

3
Legal Definitions

• RCW 51.08.100"Injury."
• "Injury" means a sudden and tangible happening,
  of a traumatic nature, producing an immediate or
  prompt result, and occurring from without, and
  such physical conditions as result therefrom.
• RCW 51.08.140"Occupational disease."
• "Occupational disease" means such disease or
  infection as arises naturally and proximately out
  of employment under the mandatory or elective
  adoption provisions of this title.

4
Criteria For Allowance

• Physician opinion more probable than not that
  work conditions are the cause of or have
  temporarily or permanently aggravated a
  pre-existing condition
• Supporting objective medical findings
• Arose naturally and proximately out of employment

5
Naturally

• A natural consequence of distinctive conditions
  of employment OR
• A natural consequence of work conditions rather
  than conditions in everyday life or all
  employment in general OR
• A natural consequence of conditions of employment
  rather than conditions occurring coincidentally
  in the workplace

6
Proximately

• There existed no intervening independent and
  sufficient cause for the disease so that the
  disease would not have been contracted but for
  the distinctive condition existing in the
  employment
• not required to be the only cause

7
Statute of Limitations

• Injury - 1 year from diagnosis
• Disease - 2 years from diagnosis

8
Categories of Occupational Disease

• Cumulative trauma
• Other musculoskeletal disorders
• Dermatitis
• Respiratory disease
• Neurological disease
• Other systemic disorders

9
Cumulative trauma

• Epidemiolologic controversy
• Science v. administrative acceptance
• Non work factors
• Crossover with injuries
• Discrete syndromes v. regional pain

10
Epidemiologic controversy

• Common in general population
• lack of clear dose-response relationship
• force, frequency, postures, vibration
• Anthropometric variability
• multifactorial causation

11
Science v. administrative acceptance
12
Non work factors

• Sporting or hobby activities
• Prior injury
• Systemic disease
• Psychosocial stressors

13
Crossover with injuries

• Acute strain v. repetetive trauma
• Objective findings the same
• Coding and Diagnosis
• e.g. Wrist strain vs tendonitis

14
Points of View

• Injured worker
• Employer
• Attending Provider
• Specialist
• Claims manager

15
Causal Inference

• Qualitative plausibility
• Quantitative plausibility
• Temporal relationship
• Elimination of alternative explanations

16
Temporal Relationship

• Exposure precedes disease
• Symptoms occur in proper relationship to exposure
• Acutely during exposure, disappearing after
  exposure ceases, better on evenings, weekends and
  holidays
• Chronologicaly appropriate duration and latency
  period

17
Qualitative Plausibility

• Is the disease/symptoms consistent with the known
  toxic effects of the substance?
• In the absence of adequate literature
• Are there others similarly exposed experiencing
  the same disease
• Does the offending substance share chemical or
  structural characteristics with other substances
  known to cause the disease

18
Quantitative Plausibility

• Was the exposure level sufficient to cause the
  disease?
• Comparison of the individuals exposure to
  published toxicology and epidemiology literature.

19
Alternative causation

• Is there a more likely or preferable explanation
  of causation?
• Natural course of pre-existing disease
• new disease onset of other cause
• concurrent disease process resulting in some of
  symptoms
• multifactorial cause

20
Occupational Diseases

• Acute vs. chronic exposure
• Transient vs. cumulative exposure
• Exposure often remote from disease
• cumulative exposures - Cadmium, lead, asbestos
• latency periods - Cancer, asbestosis

21
Reconstruction of Exposure

• Duration
• Nature of agent
• Controls
• Intensity
• Personal protective equipment
• Engineering controls

22
Sources of Information

• Patient history
• Medical Records - outside PMDs, present and
  prior
• Medical surveillance
• MSDSs
• Industrial hygiene measurements
• Human resources
• Worksite walk through

23
Epidemiology and Toxicology of Occupational
Disease

• Study Quality
• Variety of Study Types
• Animal v. human data
• Similar type and route of exposure
• Random variation
• Bias
• Statistical v. clinical significance

24
Epidemiology Interpretation

• Strength of Association
• Consistency between studies and groups
• Specificity - exposures and disease
• Dose -Response relationship
• Coherence and Plausibility
• Temporality

25
Study Design Pyramid
Relative Value
26
(No Transcript)