Diagnostics of occupational asthma (history, exposure, allergologigal investigations, differential...
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Transcript of Diagnostics of occupational asthma (history, exposure, allergologigal investigations, differential...
Diagnostics of occupational asthma
(history, exposure, allergologigal investigations, differential diagnostics)
H. Keskinen MD
Finnish Institute of Occupational Health
Occupational asthma, diagnostics
work-related asthmatic symptoms
exposure to a sensitizing agent at work
cause-effect relationship between the exposure and asthma– sensitization (skin prick tests / specific IgE
antibodies)– typical long-term PEF surveillance – positive provocation tests
Occupational asthma, symptoms
Cough, production of mucus, dyspnea related to work
– during working hours– in the evening after the work day– during the night after work days
no symptoms during days off later symptoms also during weekends,
but improving when away from work for longer periods
Causes of cough/dyspnea
bronchial asthma respiratory infections COPD hyperventilation medication reflux disease cardiac causes malignant disorders
Occupational asthma/ history
What is your work? (ask every patient with cough/dyspnea!)
What are the symptoms? When did they begin? How are they related to work? Specific agents ? old? new? Change in working habits? Change in the work environment? Symptoms of respiratory infection? Smoking?
Occupational asthma, exposure
exposure in own work exposure as bystander
– other work procedures in the same hall– from the neighbouring hall
non-occupational sensitizing agents – pets– hobbies
Exposure, sources of data
patient occupational health services employer safety data sheets importer/manufacturer registers of occupational
diseases literature
Bakery work, sensitizers
flours enzymes storage mites spices egg milk powder sesame seed
Cattle breeding, sensitizers
animal epithelia feed grains (rye, barley,
wheat) storage mites natural rubber feed additives? (fish
powder, enzymes, soya)
diisocyanates (TDI, MDI, HDI) epoxy resins, organic acid anhydride or amine hardeners phthalates formaldehyde azodicarbonamide cyanoacrylates methacrylates polyfunctional aziridine hardener
Manufacturing/use of plastic products, sensitizers
Health services, sensitizers clinics
– natural rubber– chloramine T– glutaraldehyde– formaldehyde– animal epithelia (veterinary
work)
dental care– natural rubber– methacrylates– chloramine T– formaldehyde– ammonium persulphate
Hair dressers, sensitizers
Persulphates Permanent wave chemicals Hair sprays Dyes Natural rubber
Electronics, sensitizers
Soft soldering fumes (colophony) Diisocyanate cured varnishes Formaldehyde Epoxy resins, organic acid anhydrides Acrylate glues
Painting, sensitizers
Formaldehyde Diisocyanate cured paints Epoxypaints, amine hardeners Epoxy powder paints Polyester powder paints Paints with azidirine hardeners
Wood works, sensitizers
Formaldehyde (glues and shellacks) Wood dusts (exotic woods!) Diisocyanate hardened paints Aziridine hardened paints Moulds (mouldy wood dusts)
Metal work, sensitizers
Welding fumes (MMA) and grinding dusts of stainless steel
Hard metal dust Welding fumes of painted steel (2-component
paints) Aerosols of cutting fluids Other welding fumes?
Basic investigations
physical status, lung auscultation chest X-ray (also nasal sinuses if needed) blood sedimentation rate, CRP, blood count,
eosinophils spirometry, also after bronchodilating medicine histamine/metacholine challenge exercise test (EKG, FEV1, blood gases), if needed diffusion capacity, if needed total IgE skin prick tests (common environmental allergens)
Investigations of allergy/environmental allergens
Skin prick tests (SPT) – common environmental allergenes
(pollen of trees/grasses, animal epithelia, house dust mites, moulds, natural rubber)
– commercial extracts (ALK Abello, Denmark)
Total IgE Determination of specific IgE
– if skin prick test not possible– specific allergens, not available as SPT– commercial tests (Pharmacia, Sweden)
Skin prick tests, sensitizing agents at work
Skin prick tests– commercial extracts (ALK Abello, Denmark)
e.g.: flours, animal epithelia, moulds, storage mites, natural rubber (chemicals not commercially available as SPT!)
– "in-house" extracts (quality? testing of control persons!)
freeze-dried allergenschemicals, conjugated with HSA
Note: - extracts of work-related sensitizers not standardized, wrong negative/positive tests?!
- only IgE-mediated allergies are found
Determination of specific IgE, sensitizing agents at work
– commercial tests (Pharmacia, Sweden)
(flours, animal epithelia, moulds, storage mites, natural rubber, chloramineT, diisocyanates, acid anhydrides, formaldehyde)
– "tailor made" tests
Note: – extracts of work-related sensitizers not
standardized, wrong negative/positive tests?!– only IgE-mediated allergies are found
Chemicals and specific IgE
Asthma due to diisocyanates - only about 20% of the diagnosed cases have been IgE-mediated (RAST +:ve)
Asthma due to organic acid anhydrides - most often RAST +:ve
Occupational asthma due to formaldedyde - rarely RAST +:ve
Negative RAST does not exclude occupational asthma!
Occupational asthma, differential diagnostics
Non-occupational allergies– e.g. pollen, pets – constant asthma symptoms, irritants at work cause
increasing symptoms
Intrinsic-type asthma– all irritants and strain, also at work, increase symptoms
COPD– marked obstruction, strain and irritants increase symptoms
Occupational asthma, diagnostics
history– work-related asthmatic symptoms– exposure to a sensitizing agent at
work
clinical investigations for verifying the cause-effect– sensitization to agents at work– cause-effect relationship between the
exposure and astma of the patient