Occupational Health Unit

1
Basic Concepts in Occupational Medicine

• Occupational Health Unit
• Royal Free Hospital

2
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 history
• 2. Identify factors or patterns in a patients
  history that may indicate a work related
  contribution to ill health
• 3. Consider a work related health dilemma and
  reach a conclusion with reasons
• 4. 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 individuals
  medical fitness for work

3
Occupational Health

• Work Health
• (occupational disease/work related ill health)
• Health Work
• (medical fitness for work)

4
Occupational Health/Therapy

• Occupational Medicine/Health
• a branch of medicine concerned with the
  interaction between health and work (occupation)

• Occupational Therapy
• assessment treatment to enable maximum
  independent function in daily living, using
  purposeful activity (occupation)

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Case 1 The Hazards of Work

• You 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 doesnt 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 managers
  questions?

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Classification of work hazards

• Physical
• Mechanical
• Chemical
• Biological
• Psychosocial

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Hazard and Risk

• Hazard potentially harmful
• Risk probability of harm
• (quantifiable as risk assessment)

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Principles of Control of Workplace Hazards

• Identify
• Evaluate
• Control
• Eliminate
• Substitute
• Enclose/separate
• PPE/vaccinate

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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?
•  

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Presentation of Occupational Disease

• Pathology
• Timing of symptoms
• Possible causes
• Elicit relevant history

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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)

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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

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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

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Dose response relationship
KOH 2006
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UK detergent factory incidence of occupational
asthma vs enzyme use
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UK detergent factory incidence of occupational
asthma vs enzyme use
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UK detergent factory incidence and new employees
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UK detergent factory incidence among new
employees vs enzyme use
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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

20
Investigation of a case of suspected Occupational
Asthma

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

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(No Transcript)
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Management

• Drug treatment
• as for non-occupational asthma
• Non-drug treatment
• Remove from exposure
• Review work place
• Is prevention possible?
• Are control measures adequate?
• Compliance with (COSHH) regulations?
• Health surveillance

23
UK Supermarket bakeries
What happens when a supermarket opens?
No cases of occupational asthma
Increased incidence of occupational asthma
24
Occupational Dermatitis

• Endogenous (constitutional)
• Exogenous (contact)
• Irritant (acute/chronic)
• Allergic (immediate/delayed)

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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

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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

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History

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

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Management

• Avoid exposure
• Allergen/irritant replacement
• Skin protection
• Change job
• Drug treatment

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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

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Industrial Injuries Disablement Benefit

• Prescribed diseases (IIAC)
• relevant disease
• relevant occupation
• Administered by DWP

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Case 3 Assessing fitness for work

• Y 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?

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Fitness for work

• Job
• Relevant medical history
• Risks (self, colleagues, employer, public)

33
A Model Framework for Assessment of Medical
Fitness for Work
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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 history
• 2. Identify factors or patterns in a patients
  history that may indicate a work related
  contribution to ill health
• 3. Consider a work related health dilemma and
  reach a conclusion with reasons
• 4. 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 individuals
  medical fitness for work