First Aid, Chapter 7 Hypersensitivity Disorders, Occupational Disease

Question 1

What is occupational asthma?

Answer 1

Form of work-related asthma characterized by bronchial hyperresponsiveness, airway inflammation and obstruction related to specific exposure only in the workplace

Question 2

What percent of adult asthma is due to occupational asthma?

Answer 2

10-25%

Question 3

How is occupational asthma excluded?

Answer 3

Methacholine challenge performed when patient symptomatic and at work if negative excludes OA.

Question 4

What types of workers most commonly experience occupational asthma? What are the percentages?

Answer 4

It is reported in up to 30% of animal workers, 10% of snow crab workers, 10% of bakers, and 10% of isocyanate handlers

Question 5

What is a typical progression of occupational asthma during the work week?

Answer 5

Symptoms generally get worse as the work week goes on.

Question 6

What are the mechanisms of occupational asthma? What are the agents that cause each type? What is the timing of symptoms of each type?

Answer 6

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

Question 7

How long do animal laboratory workers take to sensitize for occupational asthma? How about flour workers?

Answer 7

Animal lab workers take 2 years, flour workers take much longer.

Question 8

In occupational asthma, to what agents does allergic rhinitis precede the asthma?

Answer 8

Allergic rhinitis usually precedes OA for HMW agens, not LMW agents.

Question 9

Smoking is a risk factor for sensitization to which agent?

Answer 9

Platinum

Question 10

What agents are the most common causes of OA?

Answer 10

Plicatic acid, isocyanates, wheat flour, latex

Question 11

What is the agent that causes occupational asthma in Western red cedar mill, carpenters, woodworkers? Is it HMW or LMW?

Answer 11

Plicatic acid, LMW

Question 12

What is the agent that causes occupational asthma in Body shop, spray paint, and insulation, roofers, auto industry? Is it HMW or LMW?

Answer 12

Isocyanates, LMW

Question 13

What is the agent that causes occupational asthma in Welder, metal/chemical worker? Is it HMW or LMW?

Answer 13

Platinum salts, potassium dichromate, LMW

Question 14

What is the agent that causes occupational asthma in Nail salon workers? Is it HMW or LMW?

Answer 14

Acrylates, LMW

Question 15

What is the agent that causes occupational asthma in Hairdressers? Is it HMW or LMW?

Answer 15

Ammonium persulfate, LMW

Question 16

What is the agent that causes occupational asthma in Adhesives and epoxy resin, paint/plastics? Is it HMW or LMW?

Answer 16

Phthalic anhydride, LMW

Question 17

What is the agent that causes occupational asthma in Plastics, paint? Is it HMW or LMW?

Answer 17

Trimellitic anhydride, LMW

Question 18

What is the agent that causes occupational asthma in Shellac and lacquer, plastics/cleaners ? Is it HMW or LMW?

Answer 18

Amines, LMW

Question 19

What is the agent that causes occupational asthma in Drug industry workers? Is it HMW or LMW?

Answer 19

B-lactam agents, LMW

Question 20

What is the agent that causes occupational asthma in Hospital workers, laboratories? Is it HMW or LMW?

Answer 20

Formaldehyde, LMW

Question 21

What is the agent that causes occupational asthma in lab workers, pets? Is it HMW or LMW?

Answer 21

animal proteins, HMW

Question 22

What is the agent that causes occupational asthma in seafood handlers? Is it HMW or LMW?

Answer 22

crab/lobster, HMW

Question 23

What is the agent that causes occupational asthma in baker/textiles? Is it HMW or LMW?

Answer 23

Wheat, coffee, tobaccvo dust, psyllium, latex, HMW

Question 24

What is the agent that causes occupational asthma in bakers? Is it HMW or LMW?

Answer 24

wheat/soya dust, HMW

Question 25

What is the agent that causes occupational asthma in baker/pharmeceuticals? Is it HMW or LMW?

Answer 25

Enzymes (amylase, lipase, pectinase), HMW

Question 26

What are the risk factors for occupational asthma?

Answer 26

• 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)

Question 27

What does HLA DQB1*0503/0201/0301 increase the risk of?

Answer 27

TDI (toluene diisocyanate induced) Occupational asthma

Question 28

What does HLA DR3, DR7 increase the risk for?

Answer 28

Occupational Asthma in general

Question 29

What does Glutamine S transferase (GSTP1) enzyme defects cause?

Answer 29

Increased diisocyanate OA

Question 30

How should diagnosis of occupational asthma be made?

Answer 30

• 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

Question 31

What is the treatment of occupational asthma?

Answer 31

• Change work environmental exposures if can’t change jobs
  - Protective equipment -Inhaled corticosteroids and other standard asthma therapies
• Smoking cessation

Question 32

What is Reactive Airway Dysfunction Syndrome (RADS)?

Answer 32

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.