Occupational Health UnitOccupational Health UnitRoyal Free HospitalRoyal Free Hospital

Basic Concepts in Occupational Medicine

Aims & Objectives

Aim:To be able to apply the basic principles of occupational medicine to your

professional practice as doctors

Objectives:1. Know what questions to ask in order to take an appropriate and relevant

occupational history2. Identify factors or patterns in a patient’s history that may indicate a work related

contribution to ill health3. Consider a work related health dilemma and reach a conclusion with reasons4. List 3 causative agents and related work activities for occupational asthma,

allergic contact dermatitis and cancer.5. Specify what information is necessary to make a fully informed assessment of

an individual’s medical fitness for work

Occupational Health

Work Health (occupational disease/work related ill health)

Health Work (medical fitness for work)

Occupational Health/Therapy

Occupational Medicine/Health

a branch of medicine concerned with the interaction between health and work (“occupation”)

Occupational Therapyassessment & treatment

to enable maximum independent function in daily living, using purposeful activity (“occupation”)

Case 1: The Hazards of WorkYou are an occupational physician. A 31-year-old laboratory technician is referred to your clinic by her manager, because of alleged lateness

and poor performance at work. You are asked to assess whether there is an underlying medical cause for this.

 She tells you that she has not been sleeping well lately, possibly due to nocturnal coughing. She says the

lab is cold and drafty, and that by the end of the working day her right arm is aching. She says that when she told her manager, he was unsympathetic; telling her she should leave if she doesn’t like the job.

 1. What are the presenting medical problems?  2. What are the possible work-related causes of her symptoms? 3. What are the potential hazards in her workplace and how might you classify them? 4. How will you respond to the manager’s questions?

Classification of work hazards

PhysicalMechanicalChemicalBiologicalPsychosocial

Hazard and Risk

Hazard: potentially harmful

Risk: probability of harm(quantifiable as risk assessment)

IdentifyEvaluateControl

– Eliminate– Substitute– Enclose/separate– PPE/vaccinate

Principles of Control of Workplace Hazards

Case 2: Is it work-related?A 58-year-old hospital porter has been off sick for almost a year, with low back pain. He says he injured his back at work. His back

pain has not improved with physiotherapy and analgesia. He has difficulty walking up and down stairs and is breathless on exertion. His occupational history is as follows:

         Left school at 15        Had numerous labouring jobs in the construction industry for 20 years or so         Worked on a tunnelling project for 18 months        Worked as a lorry driver for a brewery for 8 years         Worked as a hospital domestic assistant for 2 years        Has been employed as a hospital porter for 11 years 1.      What occupational hazards might account for his breathlessness? 2. How would you assess whether his symptoms are work related or not? 3. What are the possible causes of his back pain? 4. What advice would you give him? 5. Is he likely to be return to work? 6. What work might he be able to do?

Pathology

Timing of symptoms

Possible causes

Elicit relevant history

Presentation of Occupational Disease

The Occupational History

What is your job? What do you do for a living? What do you do at work? What do you work

with? What is a typical working day?How long? What else?Any known hazards? Anyone else with similar

symptoms?Hobbies? (DIY, pets, gardening, chemicals)

Occupational Asthma

Occupational Asthma Asthma induced by specific substances

encountered in the work place. It may occur in individuals who would otherwise not have developed asthma

Work-related Asthma Asthma which relates to substances in the work

place (resp irritants) that exacerbate asthma in people with pre-existing asthma

Causes of Occupational Asthma

Isocynates Platinum salts Proteolytic enzymes Wood dusts Glutaraldehyde Soya bean Persulphates or henna Crustaceans or fish

products

Grain / Flour (barley, oats, wheat, maize)

Caster bean dust Laboratory animals Antibiotics Latex Soldering flux (colophony) Ispaghula Tea dust

KOH 2006

exposure

risk

Dose response relationship

UK detergent factory: incidence of occupational asthma vs enzyme use

0

2

4

6

8

10

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

% all cohort

incidence

UK detergent factory: incidence of occupational asthma vs enzyme use

0

2

4

6

8

10

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

% all cohort

40

45

50

55

60

65

70

75

80ktonnes enzyme

enzyme incidence

UK detergent factory: incidence and new employees

0

2

4

6

8

10

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

% all cohort

0

50

100

150

200new employees

new employees incidence

UK detergent factory: incidence among new employees vs enzyme use

0

5

10

15

20

25

30

35

40

1989 1990 1991 1992 1993 1994 1995 1996 1997 1998

ktonnes enzyme

40

45

50

55

60

65

70

75

80% new employees

enzyme (ktonnes) incidence (new)

Investigation of a case of suspected Occupational Asthma

History Symptoms Associated symptoms Duration Work history Is patient aware of exposure to any respiratory sensitisers at

work? Timing of symptoms (immediate /delayed) Improvement away from work Adult onset Smoking history History of atopy

Investigation of a case of suspected Occupational Asthma

Clinical investigations 2hrly PEFR Skin prick test RAST / ELISA Spirometry Bronchial challenge

Management

1. Drug treatment • as for non-occupational asthma

2. Non-drug treatment • Remove from exposure • Review work place

– Is prevention possible?– Are control measures adequate? – Compliance with (COSHH) regulations?

3. Health surveillance

What happens when a supermarket opens?

X X Xsurveillance no surveillance

UK Supermarket bakeries

Increased incidence of

occupational asthma No cases of

occupational asthma

Occupational Dermatitis

Endogenous (constitutional) Exogenous (contact)

– Irritant (acute/chronic)– Allergic (immediate/delayed)

Occupational Dermatitis

Allergic Latency Lag period Eye lid swelling Papules and vesicles Exposure to a known

sensitiser

Irritant usually involves the

hands Scaling and redness Papules and vesicles

are unusual Exposure to a known

irritant

Causes of Occupational Dermatitis

Irritant “Wet work” Soap detergents vegetable juices/fruit fish/meat dough

Allergic Latex Biocides/preservatives

(e.g. formaldehyde) Chrome salts Plant allergens (e.g. onion,

garlic, spices) Epoxy resin monomers Hairdressing chemicals

History

Duration Site Work history Exposure to known allergens/irritants Improvement away from work Treatment

Management

Avoid exposureAllergen/irritant replacement Skin protection Change job Drug treatment

Occupational Cancer

Target Organ Lung

Nasal sinuses Urothelial tract

Liver(angiosarcoma)

Carcinogen Asbestos, As, Be, Cd,

Cr(VI), Ni, Fe, BCME Ni Rubber, Dyes, Al,

Tar/pitch VCM

Industrial Injuries Disablement Benefit

Prescribed diseases (IIAC)relevant diseaserelevant occupationAdministered by DWP

Case 3: Assessing fitness for workY You are an occupational physician. A 29-year old HIV positive doctor has been offered a post on an anaesthesia

rotation. 1.    Is it relevant to know how HIV was acquired? 2.    How will you assess whether s/he is medically fit for the job? 3.    What information will you need, to make a fully informed assessment?

Fitness for work

JobRelevant medical historyRisks (self, colleagues,

employer, public)

A Model Framework for Assessment of Medical Fitness for Work

Person•Relevant medical history

•Functional capacity (physical/psychological)

Job•Demands/requirements

•Safety critical work•Hours, travel etc

Risks•Employee•Employer

•Colleagues•3rd parties

(customers/service users/public)

Fitness for Work

Aims & Objectives

Aim:To be able to apply the basic principles of occupational medicine to your

professional practice as doctors

Objectives:1. Know what questions to ask in order to take an appropriate and relevant

occupational history2. Identify factors or patterns in a patient’s history that may indicate a work related

contribution to ill health3. Consider a work related health dilemma and reach a conclusion with reasons4. List 3 causative agents and related work activities for occupational asthma,

allergic contact dermatitis and cancer.5. Specify what information is necessary to make a fully informed assessment of

an individual’s medical fitness for work