By:Shamsizadeh,Shahrooz

 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. Airway inflammation 2. Airway obstruction 3. Airway hyper responsiveness (+/-)  Reversible obstruction(+/- treatment).  As a consequence of working environment.  Not to stimuli of the outside the work.

 Sensitizer-induced O.A(immunologically)  Irritant-induced O.A(non-immunologically)  Aggravation of asthma

 High molecular weight ◦ Animal derived ◦ Planet derived ◦ Enzymes  Irritant agents ◦ Chlorine ◦ Acetic acid ◦ Isocyanides  Low molecular weight ◦ Spray paint ◦ Wood dust ◦ Acid anhydride ◦ biocides ◦ Colophony-fluxes

 H.M.W is protein & polysaccharide >5kd  Ig-E dependent or not dependent  Mast cell & macrophage  Lym CD4+,IL 4,5,13  L.M.W unknown cause  Hapten (platinum,isocyanat,anhydrid)  Platinum is with Ig-E  PMN,Lym CD8+,IL 2,INF

 Air way inflammation paramount feature of asthma.  Air way inflammation cause: ◦ Obstruction ◦ Hypersensitivity  Air way response include: ◦ Rapid(1-2h) ◦ Late (4-8 h) ◦ Dual (1-2 & 4-8 h)

 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?

 With onset of 24h  Persistence symptom for at least 12w  Objective evidence of asthma: ◦ Hyper responsiveness ◦ Response to bronchodilator  No previously asthma or COPD Calcium oxide, nitrogen oxides, welding fumes, spray paint,…

 Dose-response relationship  Duration of sensitization(>1 m up to 2year) and dependent to: ◦ Dose ◦ Duration ◦ Susceptibility  Skin contact (isocyanate) such as respiratory contact is important.  Environmental agents (smoking,platinum,O3,diesel gases,air allergen.)

1. Atopy : HMW such as detergent enzymes. 2. Smoking: 1.platinum worker is the highest risk factor 2.Laboratory animal handler 3.Tetracholorophthalic anhydride. 3. non-allergic bronchial hyper- responsiveness. 4. Genetic(diisocyanate, platinum, red cedar) 5. Upper air way symptom(rhinitis &conjunctivitis).

 Prior asthma and aggregated with work: 1.Drugs(asprin,beta bloker,tarterazin,sulphit agent) 2.Environment(O3,SO2,NO2). 3.Infections(RSV, influenza, para flu, rhinovirus). 4.Exercise (cold and dry ventilation). 5.Psychological conditions(vogues and endorphin). 6.Non active smokers.

 Related to: ◦ Air way hyper sensitivity ◦ Severity of asthma ◦ Pharmalogical control of asthma  Patient can come back to work if ◦ Exposure limited ◦ Well treated with drugs  How about sensitized O.A?

 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. Spirometry (base and serial) for work related ↓10% of FEV1 before and after. 2. Methacholine or histamin challenge test after holydays associated with 3time ↑Pc P.E.F serial (the best test for O.A). 4. Immunological tests(specific IgE→HMW &platinum) 5. FeNO, sputum induced analysis(4-6 h and Eos) 6. C.X.R

I. Occupational symptoms. II. Serial P.E.F III. Serial spirometry IV. Challenge test

Current health(during the last 4 weeks) If you run or climb stairs fast do you ever: Cough? Wheeze? Get tight in the chest? Yes/no Is you sleep ever broken by: Wheeze? Difficulty with breathing? Yes/no Do you ever wake up in the morning with: wheeze? Difficulty with breathing? Yes/no Do you ever wheeze: If you are in a smoky room? If you are in a very dusty place? Yes/no Screening questionnaire 91% sensitivity and 96 % specificity

1. Substitution 2. Ventilation 3. Change of procedure 4. Restriction of employment 5. Free from smoke 6. Accidental education 7. Environmental screening 8. Protective devices

 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

StepSymptomNight 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 FrequentFEV1 or PEF 60 percent predicted PEF variablity >30 percent High-dose inhaled corticosteroids AND Long-acting inhaled beta 2- agonists

 Associated with: ◦ 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