environmental health

Occupational Lung Diseases

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

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.

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

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.

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).

THE RESPIRATORY SYSTEM

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
• 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


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

Occupational respiratory diseases

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

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

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

Classification of OLD; Induction Periods

Short:
Asthma
Infections
Allergic alveolitis
Toxic poisonings
Long:
Pneumoconiosis
Neoplasms

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

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

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


The Pneumoconiosis
Asbestosis
Silicosis
Coal Worker’s pneumoconiosis
Berylliosis

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.

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.

Silicosis

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

Prevention and Control

Silicosis - Sandblasting Hoods and Helmets
A CERTIFIED RESPIRATOR FITTED AND TESTED IS A MUST
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
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

Prevention and Control

• Exposed workers should have regular chest X-rays for early detection; every 6 months for sandblasters and every 2 - 5 years for other workers

• If the X-rays show silicosis; avoid continued exposure

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.

Asbestosis

Asbestos Related Diseases

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

Other pneumoconiosis

Siderosis
Arc-welders' pneumoconiosis is caused by the deposition of iron oxide, Fe2O3.


Anthracosis
Coal miners often suffer from lung disease due to the coal dust they inhale as they work.

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.

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.

Diseases from organic dust

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


Diseases from organic dust
Hay; Farmer's lung
• 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.

Diseases from organic dust

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

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.

Diseases from organic dust

Bagassosis
Exposure is from moldy bagasse (pressed sugar cane).


Bird-breeder’s lung

Sugar cane workers (Nicaragua)

• 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.

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.

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

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

Primary prevention of OA

Reduce exposure
Pre-employment screening
Atopy
Genetic factors
Education
Screen for potential respiratory sensitizers

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

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?

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.

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

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

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