Transcript Evaluating Patients for Occupational and Environmental Health

Regional Care Collaborative
Evaluating Patients for
Occupational/Environmental Conditions
Douglas A Swift, MD, MSPH
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Who is this Character?
Douglas A. Swift, MD, MSPH
Clinical Associate Professor:
Environmental Health Sciences
Tulane Univ School of Public Health
Dept of Medicine
Tulane Univ School of Medicine
Co Medical Director
MHM Occupational Medicine Clinics
Full time Occupational Medicine Practice
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Introduction to Occupational &
Environmental Health
Douglas A. Swift, M.D., M.S.P.H.
Occupational/Environmental Health:
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Broad Discipline Concerned with
Health & Relationship To
Work/Environment
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Recognize and prevent
occupational/Environmental
disease and injury
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Promote health in the workplace
and the community
Occupational/Environmental
Health Team
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Industrial Hygienist
Safety Specialist
Occ. Health MD
Occ. Health Nurses
PA/NP-Mid Level
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Toxicologist
Epidemiologist
Medical Specialist
Public Health
Specialist
Engineers
Team Work: Other Disciplines Utilized in
Occupational/Environmental Health
Chemistry
 Physics
 Biology
 Economics
 Business
 Law
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Occupational Physicians
Subspecialty Within Preventive
Medicine-Board Certification Available
 Prevention and early detection of
occupational/environmental disease
 Treatment of
occupational/environmental disease
 Focus on the individual & Group
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Occupational/Environmental
Toxicology
Hazard identification
 Setting exposure standards
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» dose
» duration
» frequency
Route of exposure
 Type of effects/ biological monitoring
 Severity of effects
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Public Health Prevention
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Primary Prevention
» Control at the Source-Prevent Occurrence
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Secondary Prevention
» Screening-early recognition
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Tertiary Prevention
» Minimize Disability
Primary Prevention:
Measures designed to promote general
health or specific protection against disease
agents or the establishment of barriers
against agents in the environment
 Control at the source
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» Air sampling
» Ventilation and engineering controls
» Personal Protective Equipment
» Substitution, Engineering Ergonomics &Training
Secondary Prevention
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Prompt and adequate treatment of the
pathogenic process as soon as
detectable
» Medical screening:
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Audiograms
PFT’s
TB Skin Tests
Carpal Tunnel
» Health surveillance Examinations
Tertiary Prevention
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Corrective therapy when disease has
advanced beyond early stages, in order
to prevent sequelae and limit disability,
or to address rehabilitation.
» Treatment of disease or injury
» Transition back into the workplace
» Rehabilitation
Difficulty in Estimating
Occupational Disease
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Medical problem not identified
Medical problem not recognized as workrelated
Disincentives for reporting
No reporting for particular disease
Reporting requirements not enforced
Legal or economic issues prevent reporting
Iceberg of Occupational
Disease
Recognized as
Work Related
Reported
Not Reported
Symptoms Present
No Diagnosis
Asymptomatic
Diagnosed but
not recognized as
Work Related
Common Myths re
Work Related Disease/Risk
“ It can’t be a bad place to work, she’s
been working there 45 years and there’s
nothing wrong with her”
 “ There is no excess cancer. Our
working population is healthier than the
general population “
 There can’t be a problem, our
exposures are within the OSHA PEL’s “
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Hazardous Material Exposure:
Occupational and
Environmental
Clinical Assessment
Sources of Exposure and
Assessment
A.
Environment: (personal vs. Occupational)
B.
Environmental:
» Food & water (hazardous waste)
» Pesticides (herbicides,chlordane,
organophosphates)
Sources of Exposure and
Assessment (Continued)
B. Environmental (cont.)
– Cleaning products (NH3 , CL2, solvents,
caustics)
– Structural materials: (asbestos, wood dust)
– Hobbies: (paints, solvents, art, strippers)
Sources of Exposure and
Assessment (Continued)
C. Personal:
– Smoking
– Alcohol
– Drugs
– Medications
– Supplements, herbals, vitamins
D. Occupational
Evaluation of the Patient With a
Possible Chemical Exposure
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First step:
History :
– Chief complaint – list of all medical complaints
with a brief time of onset descriptor, e.G. “
Shortness of breath for past 2 weeks “, “ tingling in
my feet for the past several months “
Evaluation of the Patient With a
Possible Chemical Exposure
History:
A. HPI- temporal sequence
– Who, what, when, where, why
B. Retrospective employment history
C. Past history of occupational and nonOccupational illnesses
D. Hospitalizations and surgeries/injuries
Evaluation of the Patient With a
Possible Chemical Exposure
History:
E. Atopic history:
Asthma, seasonal allergies, atopic skin
disorders
F. Habits/social history:
Smoking
Alcohol use
Drug use
Vitamins/supplements
Evaluation of the Patient With a
Possible Chemical Exposure
History:
G. Medications, past and present
H. Review of systems, a structured
questionnaire of symptoms by organ
system
Toxicokinetics
Substance in environment
Air, water, surfaces
Absorption
Ambient
Monitoring
(External Dose)
Excretion
Distribution
Biotransformation, Metabolism, Storage
Biological
Monitoring
(Internal dose)
Distribution, Parent Compound, Active
Metabolites, Inactive Metabolites
Binding to Critical Sites
Early subclinical
Adverse effects
Health
Screening
Surveillance
Occupational/Environmental
Disease
Clinical
Evaluation
Evaluation of the Patient With a
Possible Chemical Exposure (Cont.)
End-organ
toxicity:
Hepatic (CMP)
Cardiac (CMP)
Renal (CMP)
Endocrine/reproductive
(sperm counts)
Hematologic (CBC)
Central nervous system
Pulmonary (PFT, CT, XR)
Peripheral nervous
system (EMG, NCV)
Medical Applications of the MSDS Sheet
A. Correct identification of the compound
- Chromate versus chlorate
B.Contaminants
- E.G., HF, benzene (toluene)
C.
Rank order and relative percentage
Medical Applications of the MSDS Sheet
D.
Physical properties: state, vapor
pressure, solubility - fat vs. Water
Ability to cross cell membranes, evaporate into
gaseous state
Phosgene vs. Chlorine exposures
Chlorpyrifos exposures
E.
Thermal degradation products/
Products of combustion
- Very important
CO, CN-
Medical Applications of the MSDS Sheet
F. Unknown compounds: LD-50 in rats and
other mammals
G. CAS number - computer database
Search
H. Phone numbers - toxicologists and
Referrals to physicians familiar with
Toxic properties of the substance.
I. Determine if the substance is considered a
carcinogen, mutagen, or teratogen
OEM Opportunities in
Primary Care
Where does primary care fit in?
• Occupational Environmental History
• Asthma: cause?
• Hearing Loss: cause?
• Rash, calluses: cause?
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Agency for Toxic Substances and Disease Registry Case Studies in Environmental Medicine
Taking an Exposure History
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Agency for Toxic Substances and Disease Registry Case Studies in Environmental Medicine
Taking an Exposure History
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Causes of Occ Asthma
Mechanism
No Sensitization:
Anticholinesterase effect
Endotoxins
Airway inflamation RADS
With Sensitization:
High MW Agents, IgE mediated
complete allergens
Low MW Agents IgE mediated,
Haptens
Mechanism unclear
Examples
Organophosphates (agriculture)
Cotton Dust (textile workers)
Acids, NH3, Cl2,
Animal and plant proteins (lab
workers, bakers)
Antibiotics, metals (pharmaceutical
workers, metal workers)
Isocyanates, acid anhydrides, plicatic
acid (epoxy paints, polyurethanes,
western cedar)
Modified From LaDou: Current Occ & Env Med, 4th ed
Causes of Hearing Loss
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Conductive HL
– External Ear
» ear wax / foreign
body
» otitis externa
– Middle Ear
» trauma
» otitis media
» otosclerosis
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Sensorineural
(Nerve Deafness)
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Trauma
Noise
Infection
Ototoxicity
» Drugs, Chemicals
– Tumor (neoplasms)
– Degenerative
» presbycusis
What Caused the Reddening?
Degreaser’s Flush TCE
Causation
Causation vs. Association
1.
2.
3.
4.
Sleeping with your shoes on is associated with H/A
Ice cream sale volume is associated with drowning
Because the rooster crows the sun rises
Windmill rotation speed directly proportional to wind
velocity
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ASSOCIATION VS. CAUSE-EFFECT
HILL EPIDEMIOLOGIC CRITERIA:
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TEMPORAL (EXPOSURE PRECEDES
DISEASE)
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STRENGTH (RELATIVE RISK, ODDS RATIO)
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DOSE RESPONSE (INCREASED EXPOSURE,
INCREASED INCIDENCE)
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CONSISTENCY (SAME RESULTS IN
DIFFERENT STUDIES)
ASSOCIATION VS.
CAUSE-EFFECT (cont.)
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SPECIFICITY (SAME DISEASE OR
ORGAN SYSTEM IN DIFFERENT
STUDY)
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COHERENCE (BIOLOGICAL PLAUSIBILITY)
Association vs.. Cause/Effect
Know the Strength of the Literature
VALIDITY
STUDY DESIGN,DECREASING VALIDITY:
INTERVENTIONAL TRIALS
PROSPECTIVE COHORT
RETROSPECTIVE COHORT
NESTED CASE CONTROL
CASE CONTROL
CROSS SECTIONAL
ECOLOGICAL
CASE STUDY
ANECDOTES
Causation II
Based on the scientific literature, the following factors should be considered in determining
whether exposure to a certain substance is the cause of a particular symptom, condition,
or disease.
There should be evidence that :
Exposure to the substance, I.e. history compatible with exposure
Exposure leading to an internal dose in the subject.
The internal dose is sufficient to cause a specific effect, condition, or disease.
The specific effect, condition, or disease is recognized in the literature to be caused by the
substance or chemical in humans.
The effect, condition, or disease is temporally associated with the exposure
to the substance or chemical, i.e., the exposure preceded the effect in question.
The link between the exposure to the substance or chemical and the effect in question
is biologically plausible.
Confounding factors ( alternative causes ) have been eliminated as possible causes
for the symptom, condition, or disease.