First Aid, Chapter 7 Hypersensitivity Disorders, Occupational Disease Flashcards
What is occupational asthma?
Form of work-related asthma characterized by bronchial hyperresponsiveness, airway inflammation and obstruction related to specific exposure only in the workplace
What percent of adult asthma is due to occupational asthma?
10-25%
How is occupational asthma excluded?
Methacholine challenge performed when patient symptomatic and at work if negative excludes OA.
What types of workers most commonly experience occupational asthma? What are the percentages?
It is reported in up to 30% of animal workers, 10% of snow crab workers, 10% of bakers, and 10% of isocyanate handlers
What is a typical progression of occupational asthma during the work week?
Symptoms generally get worse as the work week goes on.
What are the mechanisms of occupational asthma? What are the agents that cause each type? What is the timing of symptoms of each type?
Immunologic:
-IgE Can be polyimmunogenic (IgE/IgG), caused by HMW agents or prtoein/polysaccharide, there is a latency period with variable onset
-haptens with protein (albumin), LMW agens, chemicals
Non-immunologic:
Irritant-RADS (Reactive airways dysfunction syndrome)/IrIA (irritant-induced asthma) caused by gases/fumes, timing is immediate no latency
How long do animal laboratory workers take to sensitize for occupational asthma? How about flour workers?
Animal lab workers take 2 years, flour workers take much longer.
In occupational asthma, to what agents does allergic rhinitis precede the asthma?
Allergic rhinitis usually precedes OA for HMW agens, not LMW agents.
Smoking is a risk factor for sensitization to which agent?
Platinum
What agents are the most common causes of OA?
Plicatic acid, isocyanates, wheat flour, latex
What is the agent that causes occupational asthma in Western red cedar mill, carpenters, woodworkers? Is it HMW or LMW?
Plicatic acid, LMW
What is the agent that causes occupational asthma in Body shop, spray paint, and insulation, roofers, auto industry? Is it HMW or LMW?
Isocyanates, LMW
What is the agent that causes occupational asthma in Welder, metal/chemical worker? Is it HMW or LMW?
Platinum salts, potassium dichromate, LMW
What is the agent that causes occupational asthma in Nail salon workers? Is it HMW or LMW?
Acrylates, LMW
What is the agent that causes occupational asthma in Hairdressers? Is it HMW or LMW?
Ammonium persulfate, LMW
What is the agent that causes occupational asthma in Adhesives and epoxy resin, paint/plastics? Is it HMW or LMW?
Phthalic anhydride, LMW
What is the agent that causes occupational asthma in Plastics, paint? Is it HMW or LMW?
Trimellitic anhydride, LMW
What is the agent that causes occupational asthma in Shellac and lacquer, plastics/cleaners ? Is it HMW or LMW?
Amines, LMW
What is the agent that causes occupational asthma in Drug industry workers? Is it HMW or LMW?
B-lactam agents, LMW
What is the agent that causes occupational asthma in Hospital workers, laboratories? Is it HMW or LMW?
Formaldehyde, LMW
What is the agent that causes occupational asthma in lab workers, pets? Is it HMW or LMW?
animal proteins, HMW
What is the agent that causes occupational asthma in seafood handlers? Is it HMW or LMW?
crab/lobster, HMW
What is the agent that causes occupational asthma in baker/textiles? Is it HMW or LMW?
Wheat, coffee, tobaccvo dust, psyllium, latex, HMW
What is the agent that causes occupational asthma in bakers? Is it HMW or LMW?
wheat/soya dust, HMW
What is the agent that causes occupational asthma in baker/pharmeceuticals? Is it HMW or LMW?
Enzymes (amylase, lipase, pectinase), HMW
What are the risk factors for occupational asthma?
- History of atopy (especially cat/dog in laboratory workers/vets)
- Smoking
- HLA DQB1*0503/0201/0301 increase risk of TDI (toluene diisocyanate induced) OA
- HLA DR3, DR7 increases risk for OA in general
- Glutamine S transferase (GSTP1) enzyme defects (increased diisocyanate OA)
What does HLA DQB1*0503/0201/0301 increase the risk of?
TDI (toluene diisocyanate induced) Occupational asthma
What does HLA DR3, DR7 increase the risk for?
Occupational Asthma in general
What does Glutamine S transferase (GSTP1) enzyme defects cause?
Increased diisocyanate OA
How should diagnosis of occupational asthma be made?
- history
- SPT/sIGE to occupational allergens and correlate with airflow obstruction via spiro on exposure
- PFTs at baseline and serially, check after exposure to agent if normal initially
- methacholine challenge
- CXR
- Gold standard is inhalational challenge
What is the treatment of occupational asthma?
- Change work environmental exposures if can’t change jobs
- Protective equipment -Inhaled corticosteroids and other standard asthma therapies - Smoking cessation
What is Reactive Airway Dysfunction Syndrome (RADS)?
Also called irritant induced asthma (IrIA); nonimmunologic process secondary to high-dose single exposure to irritant agent. Symptoms are immediate, there is no latency period, and can last a long time.
