Download Asthma

By:Shamsizadeh,Shahrooz
1386.08.23
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Respiratory diseases cause loss of 5-38
million days per year.
Asthma is the most common occupational
respiratory disease In under development
countries.
5-10% of U.S member.
15-20% of asthma cause from work.
1.
2.
3.
Airway inflammation
Airway obstruction
Airway hyper responsiveness (+/-)
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Reversible obstruction(+/- treatment).
As a consequence of working environment.
Not to stimuli of the outside the work.
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Sensitizer-induced O.A(immunologically)
Irritant-induced O.A(non-immunologically)
Aggravation of asthma
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High molecular weight
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Animal derived
Planet derived
Enzymes
Irritant agents
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Chlorine
Acetic acid
Isocyanides
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Low molecular weight
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Spray paint
Wood dust
Acid anhydride
biocides
Colophony-fluxes
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H.M.W is protein & polysaccharide >5kd
Ig-E dependent or not dependent
Mast cell & macrophage
Lym CD4+,IL 4,5,13
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L.M.W unknown cause
Hapten (platinum ,isocyanat ,anhydrid)
Platinum is with Ig-E
PMN,Lym CD8+,IL 2,INF
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Air way inflammation paramount feature of
asthma.
Air way inflammation cause:
◦ Obstruction
◦ Hypersensitivity
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Air way response include:
◦ Rapid(1-2h)
◦ Late (4-8 h)
◦ Dual (1-2 & 4-8 h)
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Rapid Airway Dysfunction Syndrome (RADS)
Single high level of exposure to irritant fume ,
gases and smoke.
Short duration between exposure and
response.
Immunologic and neurological inflammation
is the mechanism of RADS.
Is RADS come to asthma?
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With onset of 24h
Persistence symptom for at least 12w
Objective evidence of asthma:
◦ Hyper responsiveness
◦ Response to bronchodilator
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No previously asthma or COPD
Calcium oxide , nitrogen oxides , welding fumes , spray paint,…
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Dose-response relationship
Duration of sensitization(>1 m up to 2year)
and dependent to:
◦ Dose
◦ Duration
◦ Susceptibility
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Skin contact (isocyanate) such as respiratory
contact is important.
Environmental agents
(smoking,platinum,O3,diesel gases ,air
allergen.)
1.
2.
Atopy : HMW such as detergent enzymes .
Smoking:
1. platinum worker is the highest risk factor
2. Laboratory animal handler
3. Tetracholorophthalic anhydride.
3.
4.
5.
non-allergic bronchial hyperresponsiveness.
Genetic(diisocyanate, platinum, red cedar)
Upper air way symptom(rhinitis
&conjunctivitis).
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Prior asthma and aggregated with work:
1.
2.
3.
4.
5.
6.
Drugs(asprin,beta bloker,tarterazin,sulphit agent)
Environment(O3,SO2,NO2).
Infections(RSV, influenza, para flu, rhinovirus).
Exercise (cold and dry ventilation).
Psychological conditions(vogues and endorphin).
Non active smokers.
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Related to:
◦ Air way hyper sensitivity
◦ Severity of asthma
◦ Pharmalogical control of asthma
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Patient can come back to work if
◦ Exposure limited
◦ Well treated with drugs
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How about sensitized O.A?
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Dyspnea ,cough , wheezing.
Some or all of persons involved.
Latency(month to years or acute)
Onset(rapid , late , dual)
History of atopy , rhinitis , conjunctivitis
Environmental investigation
◦ Ventilation , protective devices
◦ Proper usage
1.
2.
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6.
Spirometry (base and serial) for work related
↓10% of FEV1 before and after.
Methacholine or histamin challenge test after
10-14 holydays associated with 3time
↑Pc20.
P.E.F serial (the best test for O.A).
Immunological tests(specific IgE→HMW
&platinum)
FeNO, sputum induced analysis(4-6 h and
Eos)
C.X.R
I.
II.
III.
IV.
Occupational symptoms.
Serial P.E.F
Serial spirometry
Challenge test
Current health(during the last 4
weeks)
91% sensitivity and
96 % specificity
If you run or climb stairs fast do you
ever:
•Cough?
•Wheeze?
•Get tight in the chest?
Is you sleep ever broken by:
•Wheeze?
•Difficulty with breathing?
Do you ever wake up in the morning
with:
•wheeze?
•Difficulty with breathing?
Do you ever wheeze:
•If you are in a smoky room?
•If you are in a very dusty place?
Yes/no
Yes/no
Yes/no
Yes/no
Yes/no
Yes/no
Yes/no
Yes/no
Yes/no
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Substitution
Ventilation
Change of procedure
Restriction of employment
Free from smoke
Accidental education
Environmental screening
Protective devices
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Loss of exposure
Protective devices for RADS and work agg
asthma
Avoid from smoking ,dust ,fume (for irritant)
Follow up with:
a. Serial PFT
b. Specific challenge tests
Step
Symptom
Night
Symptom
Lung
function
medication
STEP 1: Mild
intermittent
Symptoms two times a
week
Asymptomatic and
normal PEF between
exacerbations
two times a
month
FEV1 or PEF 80
percent predicted
PEF variablity <20
percent
Exacerbations may
occur, A course of
systemic
corticosteroids is
recommended.
STEP 2: Mild
persistent
Symptoms > two times
a week but < one time
a day
Exacerbations may
affect activity
> two times a
month
FEV1 or PEF 80
percent predicted
PEF variablity 20 to
30 percent
Lo w-dose inhaled
corticosteroids
STEP 3:
Moderate
persistent
Daily symptoms
Exacerbations two
times a week
> one time a
week
FEV1 or PEF >60
but <80 percent
predicted
PEF variablity >30
percent
Low-to-medium
dose inhaled
corticosteroids and
long-acting inhaled
beta 2-agonists.
STEP 4:
Severe
persistent
Continual symptoms
Limited physical
activity
Frequent exacerbations
Frequent
FEV1 or PEF 60
percent predicted
PEF variablity >30
percent
High-dose inhaled
corticosteroids
AND
Long-acting
inhaled beta 2agonists
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Associated with:
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Exposure duration
Exposure amount after clinical symptom
Severity of symptoms(by PFT , challenge tests)
Sensitivity to west red cedar , Isocyanides
Corticosteroid inhalation
Reduce exacerbation:
◦ Proper environmental control
◦ Proper education
◦ Proper drug treatment