Medical Surveillance
JOSEPH J. SCHWERHA
MD MPH
PROFESSOR OF OCCUPATIONAL
AND ENVIRONMENTAL MEDICINE
DIRECTOR OF THE
OCCUPATIONAL AND ENVIRONMENTAL
RESIDENCY PROGRAM
GRADUATE SCHOOL OF PUBLIC HEALTH
UNIVERSITY OF PITTSBURGH
Occupational Health
surveillance entails the
systematic monitoring of health
events and exposures in working
populations in order to prevent
and control occupational
hazards and their associated
diseases and injuries.
Surveillance derives from
the French word surveiller,
“to watch over,” which
encompasses the twin
notions of careful
observation and timely
intervention.
The four essential components of
Occupational Health surveillance are:
•
To gather information on cases of occupational
diseases and injuries and on workplace exposures
• To distill and analyze data
• To disseminate organized data to necessary
parties, including workers, unions, employers,
governmental agencies, and the public; and
• To intervene on the basis of data to alter the
factors that produced these health events and
hazards
Current Occupational Health
Surveillance Activities in the U.S.A.
• Death Certificates
• Hospital Discharge Data
• Physicians’ Reports: A sentinel provider is a physician
or other health provider (or facility) who, due to their
specialty or geographic location, is likely to provide care
for workers with occupational disorders. As a part of
SENSOR at present, NIOSH provides support to 14
states to develop surveillance systems for 12
occupational conditions, including silicosis,
amputations, asthma, burns, cadmium poisoning,
carbon monoxide poisoning, carpal tunnel syndrome,
childhood injuries, dermatitis, noise-induced hearing
loss, pesticide poisoning, and tuberculosis.
Surveillance Activities continued
•
•
•
•
•
Laboratory Reports
Workers’ Compensation Reports
National Surveys
Employer Surveillance Programs
Occupational Health Clinics
Occupational Hazard
Surveillance Activities in the
United States
• OSHA Integrated Management
Information System
• NIOSH National Hazard Surveys
Evaluations for
Specific
Occupational
Exposures and
Diseases
Assessment
The type of occupational health
programs needed by any business is
directly dependent on the goals,
activities, and operations of that
organization.
Needs Assessment
The first stage of medical
surveillance is needs assessment.
“Do certain workers need
special tests?”
Assessment of Factors Outside
the Workplace
* disinfectants
* cleaning agents * paint removers
* wax strippers * solvents
* pesticides
* emissions from heating or cooling devices
* sunlamps
* a wide variety of materials used in painting, ceramics,
printmaking, sculpture and casting, welding, stained
glass, woodworking, photography, and many forms of
commercial art
Medical Surveillance
1. Upon initial assignment or institution
of medical surveillance:
a. General physical examination performed
b. Medical history taken, including the following
topics:
(1) alcohol intake
(2) past history of hepatitis
(3) work history and past exposure to
hepatotoxic agents
(4) past history of blood transfusions
(5) past history of hospitalizations
Medical Surveillance continued
c. A serumspecimen obtained,
determinations made of:
(1) Total bilirubin
(2) Alkaline phosphatase
(3) Serum glutamate oxalacetic transaminase -SGOT
(4) Serum glutamate pyruvic transaminase - SGPT
(5) Gamma glutamyl transpeptidase
(6) Acute test necessary to maintain an exposure
Medical Surveillance continued
2. Examinations provided shall be
performed to least
a. Every 6 months for certain conditions
b. Annually or age related
c. Government regulated
d. On the physician’s discretion
3. Each employee exposed to an emergency
shall be afforded appropriate medical
surveillance.
Medical Surveillance continued
4. A statement of each employee’s
suitability for continued exposure,
including use of protective equipment
and respirators, shall be obtained from
the examining physician promptly
after each examination. A copy of the
physician’s statement shall be provided
each employee.
Medical Surveillance continued
5. If any employee’s health would be
materially impaired by continuous exposure,
each employee shall be withdrawn from
possible contact.
6. Laboratory analyses for all biologic
specimens included in medical examinations
shall be performed in laboratories
licensed under 42 CFR Part 74.
Medical Surveillance continued
OHS’s must have available for staff use, in
writing, preferably in a manual, the
following desiderata:
(1) the type of examination (complete or partial,
general or specific)
(2) the interval history items to be reviewed
(3) the periodicity
(4) the organ system or organs to be given special
scrutiny
(5) the hematologic, urine, biochemical, fecal,
radiographic, cytologic, or breath analytic
procedures to be completed
Medical Surveillance continued
(6) acceptable levels for each test result
(7) the interval between a test productive
of an abnormal leave and the repetition
of the test
(8) the time of specimen collection
(9) the persons to be notified in the event
of abnormal findings
(10) other actions to be taken
Objectives of Occupational
Health Services
• To protect the health and well-being of workers against the
stressors and potential health hazards of the work
environment.
• To place job applicants or current employees in work
commensurate with their physical and emotional capacities,
work that can be performed without endangering the worker
or fellow employees and without damaging property.
• To provide emergency medical care for injured or ill workers
and definitive care and rehabilitation for those with workgenerated injuries or illnesses, in keeping with the medical,
surgical, or psychotherapeutic expertise of the staff, medical
department policy, managerial policy, and the availability of
community resources.
Objectives of Occupational
Health Services continued
• To maintain or improve the health of the
worker through promotional, educational,
counseling, or informational activities,
preventive health measures including
fitness or wellness programs, and periodic
clinical reviews of health status.
• To promote improved health among family
members.
Biological monitoring is the
measurement of a chemical, its
metabolite, or a nonadverse
biochemical effect in a biological
specimen for the purpose of assessing
exposure.
Advantages of Biologic Monitoring
1. It is an attempt to measure the parameter
most directly related to potential health effects.
Results can aid in formulating a more refined
estimate of risk of illness secondary to
exposure.
2. Nonoccupational exposures and individual
variability are assessed.
3. Multiple exposures and other routes of
exposure, such as dermal and ingestion, can be
evaluated.
Limitations of Biologic Monitoring
1. Effectiveness is dependent on adequate toxicologic
data.
2. Test results can be affected by other factors such as
alcohol and pregnancy. Cigarette smoking can also
interfere with monitoring results. Workers who smoke
cigarettes, for example, may have levels of cadmium
higher than their nonsmoking counter parts.
3. For some substances, relatively short biologic halflives affect the monitoring.
4. Monitoring is ineffective for surface-acting agents
such as sulfur dioxide and ammonia.
Variety of Periodic Medical Examinations
continued
Association of Occupational and
Environmental Medicine Clinics
(AOEC) found the following three
questions essential:
1. Please describe your job
2. Have you ever worked with any health
hazard, such as asbestos, chemicals, noise, or
repetitive motion?
3. Do you have any health problems that you
believe may be related to work?
Work and Exposure History
• Focus on the job when the patient first began
having symptoms
• Patient’s job title (or occupation): it is important to
know the nature of the job
• “Tell me what you do on your job?”
• “Is there anything you do now that is different from
past jobs where you’ve been an [electrician]?”
• Specific exposures: the exposure history requires
further study to identify specific constituents of
products and exposure levels.
• Assessment of relative levels of exposure (i.e., low,
medium, high) for specific agents can be valuable
Work History
• Change in symptoms during the work day.
• Change in symptoms over the work week.
• Change in symptoms on weekends and on
vacations.
• Onset of symptoms away from work.
• Other experiences with work-related events.
Clinical Environmental Medicine
Environmental medicine can be considered to be “the
study of effects upon human beings of external
physical, chemical, and biologic factors in the general
environment”. Clinical environmental medicine, then,
would be “the study of detectable human disease or
adverse health outcomes from exposure to these
environmental factors”. The discipline of
environmental medicine “combines clinical
epidemiologic, and toxicologic approaches. It uniquely
seeks to understand external causation and then to
adopt policy, engineering, or human factor
interventions to prevent or mitigate the caused
outcomes”.
Principles of Occupational and
Environmental Disease
• The clinical and pathologic expression of most
environmentally caused diseases are
indistinguishable from those of
nonenvironmental origins.
• Many diseases of occupational or
environmental cause are multifactorial, with
nonenvironmental factors playing a role.
• The effects of occupational and environmental
exposures occur after a biologically predictable
latent interval following exposure.
Principles of Occupational and
Environmental Disease continued
• The dose of an exposure to a noxious
agent is a strong predictor of the
likelihood and type of effect
• People differ substantially in their
responses to noxious exposures.
The Environmental Evaluation
1. Lack of specificity about the identity of
hazards
2. Inadequate information about exposure level
3. Recall biases (greater attention to exposures
that were at the time
bothersome or
otherwise are perceived as being casual)
4. Other biases, e.g., patients fearful of possible
job loss may under-report exposures, and
litigants may exaggerate the intensities of
exposures and their apparent effects
The Environmental Evaluation
continued
This additional information serves several
purposes:
1. To learn the true chemical or physical
hazards to which the patient has been exposed
2. To establish information about the dose of
exposure
3. To corroborate or modify the information
that has been obtained directly from the patient.
The Environmental Evaluation
Issues about confidentiality should always be
considered:
• Prior medical records
• Exposure records from an employer
• Health and regulatory agencies
• Unions and community groups
• Direct site visit
Exit Examinations
The structure and content of exit
examinations most closely mirrors that
of the periodic medical examination.
Exit examinations tend to be either
target-organ or substance specific and
frequently are used by employers to
document that the employee has
suffered no adverse health effects from
employment or to establish the extent of
any such effects.
Record Keeping
1. Medical surveillance
a. Establish and maintain a medical record for each employee
b. The record shall include:
(1) Name, SSN, and description of employee duties
(2) Copy of medical examination results
(3) Copy of the physician’s written opinion
(4) Complaints related to exposure
(5) Protective devices worn and length of time worn
(6) Copy of the standard and its appendices
c. The employer must maintain the record for at least 30-50 yrs
Summary of Occupational and
Environmental History and Examinations
Occupational and environmental histories and examinations
serve two main purposes in occupational health practice.
The first is to help place and maintain people in work that is
commensurate with their physical and mental capabilities.
The second usage is to monitor individuals exposed to
environmental hazards associated with work-related
diseases.
To a greater or lesser extent, all occupational and
environmental evaluations contain three basic components:
the occupational environmental history, the medical history
and review of systems, and the physical examination.
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Medical Surveillance in Occupational Health