HL1115 Influences on Health at Work

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HL1115 Influences on Health at Work

• Occupational lung disorders asthma, byssinosis,
  pneumoconiosis, asbestosis, mesothelioma, farmers
  lung, acute and chronic effects of exposure to
  toxic fumes.

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Routes of Entry
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Routes of Entry

• Mechanism vs. Pathway
• Mechanism is action
• Pathway is route of entry
• We use both terms!

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Routes of Entry

• Nasal
• Inhalation

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Routes of Entry

• Oral
• Ingestion

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Routes of Entry

• Dermal (Skin)
• Absorption
• Injection

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Routes of Entry

• Inhalation
• Ingestion
• Skin
• Absorption
• Injection

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Routes of Entry

• Target Organ vs. Pathway
• Target organ is system affected
• Pathway is route of entry
• They dont have to be the same!

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Routes of Entry

• Inhalation is particularly important exposure
  portal

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Routes of Entry
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Inhalation

• Air exchange region of lungs is around 300 square
  ft at rest and about 1000 square ft at full
  inspiration

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Inhalation
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Inhalation
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Inhalation

• Absorption Factors
• High surface area
• Small air/blood distance
• Particle size
• Solubility

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Inhalation

• Absorption Factors
• Concentration
• Duration
• Respiration Rate

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Ingestion

• Methods
• Incidental
• Accidental
• Deliberate

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Ingestion

• Absorption Factors
• Emotional state
• Digestive acids/enzymes
• Diahhrea/constipation
• Gastrointestinal content

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Ingestion

• Absorption Factors
• Micro-flora in gut
• Metabolite formation
• Age
• Predisposing factors

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Skin Absorption

• Primary layers
• Epidermis
• Dermis
• Subcutaneous layer

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Skin Absorption

• Absorption Factors
• Disease/injury state
• Blood flow, sweat heat
• Skin age
• Skin thickness

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Skin Injection

• Intraperitoneal
• Subcutaneous
• Intramuscular
• Intravenous

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Respiratory System

• Nasopharynx Region
• Tracheobronchial Region
• Pulmonary (Alveolar) Region

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Respiratory System

• Nasopharynx Region the head region, including
  the nose, mouth, pharynx, and larynx

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Respiratory System

• Tracheobronchial Region includes the trachea,
  bronchi, and bronchioles

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Respiratory System

• Pulmonary (Alveolar) Region comprised of the
  alveoli the exchange of oxygen and carbon
  dioxide through the process of respiration occurs
  in the alveolar region.

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Respiratory System
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Particle deposition

• Sedimentation

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Particle deposition

• Diffusion

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Particle deposition

• Interception

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Particle deposition

• Impaction

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Deposition of particles4-5 mm in respiratory
tract 2.5-3 mm in upper respiratory tract 2 mm
in URT and lung spaces 1 mm in alveolar spaces
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Particulate Sizing

• Inhalable Particle Mass
• Thoracic Particle Mass
• Respirable Particle Mass

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Inhalable Particle Mass - hazardous when
deposited anywhere in the respiratory tract, 50
cut point 100 mm
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Thoracic Particle Mass - hazardous when deposited
anywhere in the lung airways or gas exchange
region, 50 cut point 10 mm
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Respirable Particle Mass - hazardous when
deposited in the gas exchange region, 50 cut
point 4 mm
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Stokes Law
An equation relating the terminal settling
velocity of a smooth, rigid sphere in a viscous
fluid of known density and viscosity to the
diameter of the sphere when subjected to a known
force field.
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Stokes Law
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Stokes Law
v settling velocity g gravitational
acceleration, 9.80 m/s2 rs density of object d
diameter of object rF density of fluid m
viscosity of fluid
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Stokes Law
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Reynolds Number
laminar flow if Re lt500 turbulent flow if Re gt500
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Stokes Law

• settling velocity relates to diameter

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Pulmonary function testing(Spirometry)Pulmonary
function tests are sensitive indicators of lung
disease and are commonly used in the workplace
environment
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Common tests
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• Forced Vital Capacity (FVC)
• One Second Forced Expiratory Volume (FEV1)
• Ratio of FVC to FEV1
• Peak flow

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HL1115 Influences on Health at Work

• The most common measurements used however are
  those of FEV1, FVC, and the ratio of these two
  variables, tests which are highly reproducible
  within individuals and are easy to administer.

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Pulmonary function abnormalities are generally
categorized into two patterns obstructive or
restrictive.
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Obstructive flow impairment, such as observed
in asthma bronchitis and emphysema is indicated
by a decrease in flow (often indicated by
decreased FEV1/FVC ratio).
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Restrictive flow impairment, such as observed in
interstitial lung disease is indicated by a
decrease in volume.
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Pulmonary function tests can be given before and
after the workshift to observe changes in the
workers lung function during the workday.
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Technical Requirements for Spirometry of Good
QualityAt least 3 acceptable tests are made
with
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Spirometry Requirements
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• Full inhalation before start of test
• Satisfactory start of exhalation
• Evidence of maximal effort
• No hesitation
• No cough or glottal closure during the first
  second

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Spirometry Requirements
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• Satisfactory duration of test
• At least 6 seconds
• Up to 15 seconds in patients with airflow
  restrictions
• No evidence of leak in the system
• No evidence of obstruction of the mouthpiece

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Spirometry Requirements
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• Reproducible resultsFor FVC and FEV1, the 2
  largest values should be within 5 percent or 0.1
  liter (whichever is larger) of each other.If
  these criteria are not met testing is continued.

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Spirometry Requirements
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• If the criteria are not met after 8 trials,
  testing is stopped and the interpretation is made
  using only the 3 best acceptable tests.

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Selection of test values for interpretation
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• Tests of acceptable quality are used with the
  largest values for FVC and FEV1 used, regardless
  of test..

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Selection of test values for interpretationTests
of acceptable quality are used with the largest
values for FVC and FEV1 used, regardless of
test.
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For indexes of average or instantaneous flow
values from the test with the largest value for
FVC and FEV1 combined are used.
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Biological Reaction to inhaled dust
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Lung DiseasesFibrosis - scar tissue formation
Bronchitis - overproduction of mucus Asthma -
constriction of bronchial tubes
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Systemic reactionstoxicants adsorbed by blood
and distributed to target organs e.g. - lead,
manganese, cadmium, mercury
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Metal fume feverinhalation of finely divided,
freshly generated metal fumes Al, Zn, Mg, Cu and
their oxides
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Allergic and sensitization reactionsinhalation
of certain dusts from woods, grains chemicals
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Bacterial and fungal infectionsinhalation of
contaminated dusts from grains, textiles etc.
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Irritation of the nose and throatinhalation of
acids and alkalis soluble chromates can cause
nasal passage ulceration ( cancer)
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Internal damageinhalation of radioactive
materials
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Examples
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Allergic Alveolitis

• Also known as
• Hypersensitivity Pneumonitis (HP) or
• Extrinsic Allergic alveolitis (EAA)
• Other names include
• farmers lung
• bagassosis
• pigeon fanciers lung

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Allergic Alveolitis

• Acute symptoms include fever, chills, dyspnea,
  leukocytosis 4-6 hours after exposure and may
  recur on re-exposure.
• Chronic disease shows progressive dyspnea,
  fatigue, low-grade fever, weight loss, chronic
  nonproductive cough, and bibasilar crackles.

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Allergic Alveolitis

• a restrictive type impairment
• type III and IV hypersensitivity reaction

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Farmers Lung

• source moldy crops
• organisms
• Thermoactinomyces sacchari
• Thermoactinomyces vulgaris
• Micropolyspora faeni

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Bagassosis

• source moldy sugar cane
• organisms
• Thermoactinomyces vulgaris
• Micropolyspora faeni
• Aspergillus species

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Pigeon Fanciers Lung

• source pigeon dust and bloom
• substance
• proteins

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Byssinosis

• source cotton dust
• substance
• Endotoxin?

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Byssinosis

• chest tightness,
• cough, wheezing, dyspnea
• decreased FEV
• bronchitis malaise fever, chills,
• upper respiratory symptoms after initial exposure
  

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Byssinosis

• Stages
• only on Monday
• persistent, greater on Monday
• irreversible

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Organic Dust Toxic Syndrome (ODTS)
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ODTS

• Grain fever
• Pulmonarymycotoxicosis
• Silo unloader's syndrome
• Inhalation fever
• Mill fever

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ODTS

• Not a hypersensitivity reaction
• Does not require repeated exposures to the same
  causative agent
• May occur after a single heavy exposure to dust

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ODTS

• Fever occurs 4-12 hours after exposure followed
  by flulike symptoms such as general weakness,
  headache, chills, body aches, and cough.

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Occupational Asthma(OA)
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Common Asthmagens

• Isocyanates
• Solder fume
• Metals
• Latex
• Vegetable dusts
• Animal proteins
• Enzymes

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Occupational Asthma

• Variable airflow limitation and/or bronchial
  hyperresponsiveness from work-related exposure
• Obstuctive type impairment

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Asthma

• Characterized by episodes of airflow obstruction
  in the bronchial tubes.
• Symptoms caused by this obstruction include
  coughing, chest tightness, wheezing and shortness
  of breath.
• Although problems are often separated by
  symptom-free periods, asthma is a chronic
  illness.

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Rhinitis

• A reaction that occurs in the eyes, nose and
  throat when airborne irritants or allergens
  trigger the release of histamine.
• Histamine causes inflammation and fluid
  production in the fragile linings of nasal
  passages, sinuses, and eyelids.

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Rhinitis

• sneezing
• congestion
• runny nose
• itchy nose, throat, eyes, and ears

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Rhinitis

• Allergic rhinitis
• pollen
• dust mites
• mold
• animal dander

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Rhinitis

• Nonallergic rhinitis
• fumes
• odors
• temperature
• smoke
• other irritants

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Pneumoconiosis
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Silicosis seen in any industry using quartz
containing dusts such as stonework, foundries,
glassmaking, pottery, etc.
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Several forms of free silica quartz,
cristobalite, tridymite, fused silica dust,
tripoli silica flour inhalation of
crystalline silica (silicon dioxide) causes
fibrotic changes in the lungs
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BentoniteUses foundry sand bond, drilling mud,
clays for dams etc.Disease silicosisCause
quartz
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Fuller's earthUses adsorbent clayDisease
silicosis like pneumoconiosisCause
montmorillonite, quartz
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MicaUses drilling mud, decorative
finishesDisease radiographic changes and
fibrotic changesCause mica and silica
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BerylliosisUses - Be/Cu alloys, Be/Ni alloys,
Be ceramicsspark proof tools, aircraft brakes,
electronics
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Two diseases acute pneumonitis and chronic
berylliosis
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Acute syndrome less than a year during exposure
includes any or all of the following
nasopharyngitis, tracheitis, bronchitis,
pneumonitis, dermatitis, conjunctivitis
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Chronic longer than a year with both systemic and
pulmonary abnormalities
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A separate disease is subcutaneous granulomas
secondary to direct implantation of Be compounds
under the skin
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CWP Coal workers pneumoconiosis, "Black Lung"
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Hard metal diseaseTungsten Carbidetungsten
carbide used in abrasive tools can result in an
asthma syndrome or a diffuse interstitial fibrosis
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Mica pneumoconiosis
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Kaolinosis
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Bauxite pneumoconiosis
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Siderosis Inhalation of iron fumerelatively
benign pneumoconiosis, by itself, with fibrogenic
mineral dusts, pulmonary fibrosis termed mixed
dust pneumoconiosis or siderosilcosis
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Factors that influence the development of
pneumoconiosis
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1. Amount and kind of dust inhaled.
2. of mineral compound in the dust (concentration)
3. the crystalline structure of the mineral
4. the size of the particles inhaled

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1. duration of the exposure
2. Individual susceptibility resistance
3. Presence of other pre-disposing factors

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AsbestosAsbestosUses - insulation,
fireproofing
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Where asbestos is found
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Asbestos cement
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Sprayed asbestos
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Sprayed asbestos
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Lagging
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Asbestos insulating board
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Asbestos insulating board
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Asbestos textiles
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Several types in two main forms
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Serpentine chrysotile (white A), Amphibole -
crocidolite (blue A), amosite (brown A),
anthophyllite, tremolite and actinolite
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Asbestosis - diffuse interstitial
scarringBronchogenic carcinomaMesothelioma
(pleural or peritoneal)Cancer of stomach,
colon, rectum
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Questions?