Occupational Asthma:

Is your client's asthma misdiagnosed?

By Nachman Brautbar, M.D.

Click here to go to
The California Injured Worker Advisor's
Home Page

THIS ARTICLE IS PRINTED WITH PERMISSION OF DR. BRAUTBAR,  

Dr. Brautbar practices in the field of Internal Medicine in the Los Angeles area.  Dr. Brautbar's website is http://www.environmentaldiseases.com

According to the Occupational Safety and Health Administration, Youth Department of Labor, an estimated 11 million workers in a wide range of industries and occupations are potentially exposed to at least one of the deleterious agents known to be associated with the development of occupational asthma. Occupational factors have been associated with up to 15% of the disabling asthma cases in the United States, including 558,000 workers exposed to grain dust, 1.4 million healthcare workers potentially exposed to latex products, and others (Occupational Safety and Health Administration 05/17/00). 

Asthma can typically be characterized by intermittent breathing difficulties; however, in many of the workers, asthma is not recognized due to its very atypical presentation, such as an unexplained cough, unexplained chest tightness, and unexplained shortness of breath.  According to the Occupational Safety and Health Administration, Youth Department of Labor, asthma is a frequently serious and sometime fatal condition. 

Workers may be unaware of the possible relationship between their symptoms and their work. Commonly workers do not associate their symptoms of cough, chest tightness, irritation of the skin, or shortness of breath with their industrial exposures. Commonly, according to the various agencies specializing in asthma, employers often have inadequate surveillance procedures to measure the frequency of occupational asthma. 

Workers are exposed to a wide variety of airborne contaminants on the job, such as dust, welding fumes, gases, sandblasting dust, solvent vapors and mists. Inhaling dirty workroom air can irritate the respiratory system and cause sneezing, cough, chest tightness or difficulty in breathing. Prolonged exposure over months or years can lead to chronic long-term lung disease with a chronic disability such as chronic bronchitis, asthma, pulmonary fibrosis, and emphysema. 

HOW LONG DOES ASTHMA TAKE TO DEVELOP? 

There is no fixed period of time in which asthma can develop. Asthma is a disease which may develop from a few hours, days, weeks to many years after initial exposure (the argument that the patient cannot have contracted the asthma at work, because he was diagnosed as having asthma only "5 years after his exposures took place" is refuted scientifically). Studies carried out on platinum refinery workers show that in most cases asthma develops  in 6-12 months but may occur within 10 days or be delayed as long as 25 years (For reference, Canadian Center for Occupational Health & Safety 05/17/00). As a matter of fact, the most common form of occupational asthma is occupational asthma with latency. The latency period may vary from weeks to years (For reference, Western Australian Asthma Organization 05/17/00). 

WHEN SHOULD YOU SUSPECT OCCUPATIONAL ASTHMA?  

1.      Cough or wheeze that improves on weekends or on holidays. 

2.      A high risk occupation, especially if there are other symptoms such as skin rashes, nose irritation,
eye irritation or eczema. 

3.      Other unexplained exacerbations of preexisting well-controlled asthma.

4.      Newly diagnosed asthma in an adult (adult onset asthma).  

WHAT OCCUPATIONS ARE ASSOCIATED WITH AN INCREASED RISK FOR ASTHMA? 

OCCUPATION   AGENT  

Baker, Millers: Wheat 

Chemist, coffee bean baggers and handlers, gardeners, oil industry workers, Farmers:   Castor Beans 

Farmers, grain handlers:   Grain Dust

Cigarette factory workers:   Tobacco Dust

Drug manufacturers, mold makers in sweet factories, printers:  Gum Acacia

Gum manufacturers, sweet makers:   Gum Tragacanth

Strawberry grower: Strawberry pollen

Tea sifters and packers: Tea Dust

Tobacco farmers:  Tobacco Leaf

Woolen industry workers: Wool

Laboratory workers:  Locusts, cockroaches, grain weevils, rats, mice, guinea pigs, rabbits

Aircraft fitters: Triethyltetramine

Chemical plant worker:  Chlorine

Electronic workers:  Colophony

Foundry mold makers:  Furan based resin binder systems

Hair dressers:   Persulfate Salts

Laboratory workers, nurses:  Formalin/Formaldehyde

Meat wrappers:  Polyvinyl Chloride vapors

Paint Manufacturers:  Phthalic Anhydride

Paint sprayers:  Dimethylethanolamine

Photographic workers:  Ethylenediamine

Solderers:  Polyether Alcohol

Boat builders, foam manufacturers, office workers, plastic factory workers, refrigerator manufacturers, printers, laminators: Toluene Diisocyanate

Car sprayers:  Diisocyanate

Cement workers:  Potassium Dichromate

Chrome platers, chrome polishers:  Sodium Bichromate, Chromic Acid

Nickel platers:  Nickle Sulfate

Platinum chemists:  Chloroplantinic Acid

Rubber workers:  Naphthalene Diisocyanate

Welders:  Stainless steel fumes

Pharmacists:  Gentian Powder

Pharmaceutical workers:  Methyldopa, Salbutamol, Dichloramine, Piperazine Dihydrochloride

Carpenters, wood workers: Western Red Cedar, Cedar of Lebanon, California Redwood, African Zebra Wood

Saw mill workers, pattern workers, Health care workers:  Mansonia, Oak, Mahogany, Latex, Glutaraldehyde

Painters, Mechanics, Automotive Welders:  Solvents

(This list is by no means inclusive, but only partial)

WHEN SHOULD YOU SUSPECT AN OCCUPATIONAL LUNG DISEASE SUCH AS ASTHMA? 

First of all, the worker in an industry which is considered a high risk such as health care workers, car painters, painters, wood workers, gardeners, pesticide/insecticide sprayers, and mechanic workers. The symptomatology of discrete and otherwise medically unexplained atypical cough. chest tightness, skin irritation, eye irritation which appears as a result of a work environment which was not there before, and have a temporal relationship to the work environment exposure.

PRESENTATION OF A CASE AND ANALYSIS.

J. W, 42 years, worked for Aeronautic Supplier in the paint spraying facility. He experienced an industrial orthopaedic injury, and was referred to the company doctor. He received physical therapy, was unhappy with the treatment, and elected his own primary treating physician of choice. The primary treating physician of choice was diligent enough to take a good occasional history, and was intrigued by the patient's cough and chest tightness. The diligent doctor referred the patient to my office for a consultation.  After a detailed exposure history, non-industrial factors, absence of history of preexisting asthma absence of heavy smoking, and some typical diagnostic studies which were positive, such as the Methacholine stimulation test, the diagnosis of industrial asthma was made. Essentially what happened here was, the company physician failed to take an adequate appropriate occupational history. The company failed to screen the workers on an annual basis, and specifically this worker who worked there for 10 years, in a high risk occupation known to be associated with an increased risk of occupational lung disease, specifically asthma, and the intake person in the attorneys' office concentrated on the industrial orthopedic injuries, (since the attorney's office is not in the medical business, and is not trained to take an occupational history). It was this patient's luck to be sent to a good primary treating physician who picked up some unusual symptomatology of the chest, and quickly referred the patient to our offices. Removal of the patient from his work environment and appropriate treatment alleviated the symptoms, established a diagnosis, and required vocational rehabilitation, and a disability which included no exposure to concentration of fumes and dust particles, and in light of very abnormal oxygen saturation and oxygen exchange on metabolic exercise test, a work restriction of no heavy work

TAKE HOME MESSAGE.