1. Occupational Lung Diseases
Assistant Professor
Dr. Batool A. Gh. Yassin
Department of Family & Community Medicine
College of Medicine- University of Baghdad
2015

2. Objectives By the end of this lecture you should be able to:
Define ergonomics and list its three important domains.
List the most important etiologies of occupational lung disorders.
Identify the causative process of irritant lung reaction.
Describe occupational asthma and hypersensitivity pneumonitis.
Outline the basic principles of personal protection and prevention at workplace.

3. Ergonomics Ergon = Work Nomos =
Ergonomics: aims to establish an anthropocentric harmony within the human-tool-environment system.
Fitting the job to workers
Designing machines, tools, equipment and processes
Layout Methods of work and environment

4. The International Ergonomics Association (IEA) divides ergonomics broadly into three domains:
Physical ergonomics: is concerned with human anatomical, anthropometric, physiological and biomechanical characteristics related to physical activity.
Cognitive ergonomics: is concerned with mental processes, such as perception, memory, reasoning, and motor response, as they affect interactions among humans and other elements of a system.
Organizational ergonomics: is concerned with the optimization of socio technical systems, including their organizational structures, policy, and processes.

5. THE RESPIRATORY SYSTEM
No oxygen - live only minutes
Every cell needs constant supply of oxygen
Lungs link to supply of life-giving oxygen
From American Lung Association: Occupational Lung Diseases: An Introduction. New York, NY. Macmillan. 1979: pp 10. (5).

6. THE RESPIRATORY SYSTEM
Rest
Breathe 6 liters air/minute
Heavy exercise
Breathe over 75 liters /minute
Skin surface area
1.9m² (20 sq. ft)
Lungs surface area
28m² (300 sq. ft) rest → 93 m² (1000 sq. ft) deep breath
Susceptible to damage from inhaled toxic materials & irritants;
Surface area exposed to air is so large.
Body’s need for oxygen so great
Great impact on body….leading to disease of other vital organs

7. THE RESPIRATORY SYSTEM
NATURAL MECHANISMS against airborne hazards
Fine hairs in nose
-Front-line barrier
-Filter
-Exercise/hard work
Cough reflex
-Clears trachea & main bronchi
Special cells
- Destroy bacteria & viruses
Ciliary cells-few hrs to expect foreign material
Innermost areas of lungs- much longer to clear out

8. Occupational respiratory diseases
Biologic reaction
Inflammatory reaction
Neoplastic
changes
Asbestos,
nickel,
iron
Dust
Silica dust Asbestos dust Coal dust
Toxic Gases
SO2
NOx
Allergic reaction
(occupational
asthma)
Organic
“dusts”
Cotton
Wood dusts
Flour
Chronic Obstructive Pulmonary Disease +
Synergism with tobacco

9. Fate of inhaled particles
Large particles may get trapped in the nose or large airways
Very small ones may reach the lungs
There, some particles dissolved or may be absorbed into the bloodstream
Most solid particles that do not dissolve are removed by the body’s defenses
Toxic dusts in the range of 1-5 nm produce harmful effect

10. Diseases associated with occupational exposure
Clinical manifestations of lung diseases are the same irrespective of the etiology
Airway diseases
Asthma (reversible)
Chronic obstructive lung disease (irreversible)
Cancer
Parenchymal diseases
Hypersensitivity pneumonitis (reversible)
Diffuse fibrosis (irreversible); eg. silicosis, asbestosis

11. Classification of OLD; pathophysiology
Inflammation of airways; Inflammation of the lining of respiratory system
Obstructive Lung Diseases;
- Reversible; Occupational Asthma, Byssinosis
- Irreversible; Industrial Bronchitis , Emphysema
Restrictive Lung Diseases;
- Pneumoconiosis; Silicosis, Asbestosis
- Farmer’s Lung

12. Classification of OLD; Induction Periods
Short:
Asthma
Infections
Allergic alveolitis
Toxic poisonings
Long:
Pneumoconiosis
Neoplasms

13. Inflammation ( Irritation ) of Respiratory System
This effect can be produced by substances that are;
Soluble in water
Can produce vesicant (inflammatory) effect
The site of the effect depends on the degree of solubility;
Highly soluble Upper respiratory tract infection
Moderately soluble Middle respiratory tract infection
Sparingly soluble Lower respiratory tract infection

14. Classification of irritants
Upper respiratory tract irritants
Ammonia; inflammation of the mucosa of the eyes, nose and oropharynx
Mid-respiratory tract irritants
Chlorine; Asthma like attack
Lower respiratory tract irritants
Nitrogen dioxide; Pulmonary edema

15. Parenchymal Lung Diseases (Pneumoconiosis)
Is an occupational lung disease caused by the inhalation of inorganic dust leading to change in lung architecture
- Respirable dust; less than 10 micrometer
- Harmful dust: formed of particles smaller than 5 micrometer
Factors related to the disease:
Physical and chemical quality of dust
Concentration
Duration of exposure
Personal sensitivity
Status of immune system

16. The Pneumoconiosis Asbestosis Silicosis Coal Worker’s pneumoconiosis
Berylliosis

17. Silicosis (Grinder’s disease and Potter’s rot)
This respiratory disease was first recognized in 1705 by Ramazzini who noticed sand-like substances in the lungs of stone cutters.
Is a form of occupational lung disease caused by inhalation of crystalline silica ( quartz) dust.

18. Silicosis (Grinder’s disease and Potter’s rot)
Silica is the Main constituent of sand, so exposure is common among:
- Metal miners
- Sandstones and granite cutters
- Foundry workers
- Potters
Is marked by inflammation and scarring in forms of nodular lesions in the upper lobes of the lungs.

19. Silicosis Symptoms Dry or severe cough Fatigue Tachypnea
Loss of appetite
Chest pain
Fever
In advanced cases:
Cyanosis
Cor pulmonale
Respiratory insufficiency

20. Prevention and Control
Controlling silica dust in the workplace is key to preventing silicosis
When dust can not be controlled, as in many sandblasting industry, workers should wear protective gear, such as hoods that supply clean external air or special masks that efficiently filter out the tiny particles
Silicosis - Sandblasting Hoods and Helmets
A CERTIFIED RESPIRATOR FITTED AND TESTED IS A MUST
Such protection may not be available to all people working in a dusty area( like painters & welders), so whenever possible, abrasives other than sand should be used

21. Prevention and Control
Exposed workers should have regular chest X-rays for early detection; every 6 months for sandblasters and every years for other workers
If the X-rays show silicosis; avoid continued exposure

22. Asbestosis
Asbestos is a group of minerals with long, thin fibrous crystals
Asbestos has been in use since the late 1800s
Its use increased greatly during World War II.
Building industry (strengthening cement and plastics, insulation, fireproofing and sound absorption).
Shipbuilding industry (insulate boilers, steam pipes, hot water pipes and nuclear reactors in ships).
Car manufacturing industry has used asbestos in vehicle brake shoes and clutch pads.

23. Inhalation of asbestos fibers Restrictive lung disease
Asbestosis
Inhalation of asbestos fibers
Asbestos fibers' natural resistance to digestion
Macrophage dies off
Releasing cytokines and attracting further lung macrophages and fibroblastic cells to lay down fibrous tissue, which eventually forms a fibrous mass.
Asbestosis is the scarring of lung tissue (around terminal bronchioles and alveolar ducts)
Restrictive lung disease
The fibrotic scar tissue causes alveolar walls to thicken, reduces elasticity and gas diffusion,
Reducing oxygen transfer to the blood as well as the removal of carbon dioxide
Severe cases
Reduction in lung function due to the stiffening of the lungs and reduced total lung capacity may induce right-sided heart failure (cor pulmonale)
More than 50% of people develop plaques in the parietal pleura
Induces mesothelioma and lung cancer

24. Asbestos Related Diseases
Interstitial pulmonary fibrosis(Asbestosis)
Bronchogenic carcinoma
Pleural effusion
Fibrous plaques
Pleural fibrosis
Mesotheliomas(Malignant tumor of pleura & peritoneum)
Laryngeal neoplasms

25. Other pneumoconiosis Anthracosis Siderosis
Coal miners often suffer from lung disease due to the coal dust they inhale as they work.
Siderosis
Arc-welders' pneumoconiosis is caused by the deposition of iron oxide, Fe2O3.

26. Prevention and treatment
Diseases caused by asbestos inhalation can be prevented by minimizing asbestos dust and fibers in workplace.
Because industries that use asbestos have improved dust control, fewer people develop asbestosis today.
But mesotheliomas are still occurring in people who were exposed as many as 40 years ago.

27. Prevention and treatment
Asbestos in the home should be removed by workers trained in safe removal techniques.
Smokers who have been in contact with asbestos can reduce their risk of lung cancer by:
- Giving up smoking
- Follow up by annual chest X- ray.

28. Diseases from organic dust
Acute inflammation
Inflammatory bronchoconstriction
Chronic bronchitis
Extrinsic allergic alveolitis
Eg.: bagassosis (molasses), byssinosis (cotton dust), farmer’s lung

29. Diseases from organic dust
Farmer's Lung is an allergic disease usually caused by breathing in the dust from moldy hay (dust from any moldy crop).
The technical name for Farmer's Lung is „extrinsic allegic alveolitis ", "hypersensitivity alveolitis" or "hypersensitivity pneumonitis".
People can get Farmer's Lung by breathing in dust containing the spores of special, heat-tolerating bacteria or moulds often found on moldy crops.
Hay; Farmer's lung

30. Diseases from organic dust
Cotton; Byssinosis
Actinomyces, a thermophilic bacteria, is usually the causative agent of farmer's lung, and bagassosis.
Sugar cane; Bagassosis

31. Farmer’s Lung
In extrinsic allergic alveolitis, an antigen-antibody reaction occurs in the acute phase and leads to acute hypersensitivity pneumonitis.
If exposure continued, this is followed by a sub-acute phase, with the formation of granulomas and chronic interstitial pneumonitis.

32. Diseases from organic dust
Bagassosis
Bird-breeder’s lung
Exposure is from moldy bagasse (pressed sugar cane).
This disease is caused by the exposure to avian proteins present in the dry dust of the droppings and sometimes in the feathers of a variety of birds.
It is mainly present in bird droppings.
Sugar cane workers (Nicaragua)

33. Solutions
The best way to reduce the amount of allergens in the air and possibly prevent problems in the future, is to use a high quality air purifier.
HEPA (which stands for High Efficiency Particle Arresting) removes 99.97% of particles greater than 3 microns in size.
Bird dust and dog and cat dander are large enough to be trapped in the HEPA material.

34. Occupational asthma
Disease characterized by variable airflow obstruction and/or airway hyper responsiveness due to causes and conditions attributable to a particular working environment and not to stimuli encountered outside the workplace

35. The Occupational History;
You have to list all jobs held in their lifetime and the duration.
Do symptoms improve with weekends and vacations?
The longer they have had symptoms from occupational asthma, the less clear the connection between symptoms and work
What they did, not their title:
“brusher” drills into hard rock
“caulker” uses electric arc equipment to gouge and fuse metal plates

36. Primary prevention of OA
Reduce exposure
Pre-employment screening
Atopy
Genetic factors
Education
Screen for potential respiratory sensitizers

37. Chronic obstructive pulmonary disease (COPD)
COPD is a disease characterized by airflow obstruction that is not reversible. The airflow obstruction is usually progressive and associated with abnormal inflammatory response of the lungs to noxious particles and gases.
COPD should be considered in any patient presenting with cough, sputum production and breathlessness.
The diagnosis is confirmed by spirometry.
Result from long-term exposure to; Inorganic dust, Organic dust, Chemicals - vapors, irritants, fumes
GOLD 2001

38. Essential Questions What is the nature of the process?
What exposure in the worker’s employment history may have been responsible?
What permanent level of impairment can be
predicted?
What can be done to control or limit the disease process?
Are other people in the workplace likely to be affected, now or in the future?

39. The pattern of occupational lung; Developed countries
A reduction in manufacturing industries and stricter health and safety legislation during the past 50 years have resulted in a sharp decline in the incidence of silicosis, asbestosis, and other pneumoconioses.
Asthma is now the most common occupational respiratory disorder in these countries.

40. The pattern of occupational lung; Developing countries
The traditional occupational lung diseases are commonly seen in developing countries.
Occupational asthma is reported less often.
However, the true prevalence of asthma attributable to occupation in these countries remains unknown

41. General control and preventive measures
Awareness of occupational exposure as a cause of disease is important
Occupational history is mandatory
To establish a work relationship, objective evidence of exposure and occurrence of symptoms or changes in lung function is necessary
Reduction of exposure is the key to prevention

42. In Summary
Fitting the job to workers is important issue in occupational health
Occupational respiratory diseases may be caused by exposure to organic and inorganic dust, gases, vapours chemicals and other irritants
Pre employment and periodic medical examination is important for early detection of problem
Using personal protective devices and controlled exposure are important steps in prevention