ASTHMA

Asthma Disease

Asthma is defined as a respiratory disease caused by narrowing of the air passages. It is synonymous with difficulty in breathing, tightness of chest, nasal irritation, coughing and wheezing. The first person to use it in reference to a medical condition was Hippocrates in 450 BC, and he believed that tailors, anglers and metalworkers were more likely to be affected by the disease. Although much research has been done since, the inflammatory component of asthma was recognized only in the 1960s.

Today, asthma affects as much as 15% of the Canadian population (and this is true of other developed countries too) and has increased four fold in the last 20 years. Various reasons can be identified for this increase - Of course better diagnosis and facilities along with a greater awareness regarding the disease have played a major role. But, one cannot deny the part of increased environmental pollution. Researchers have been working on the relation between the environment and human health since long and the air we breathe is the primary cause for lung diseases like asthma, rhinitis, COPDs, etc. that affect us today.

Approximately 10 to 15% of the adults affected by the disease report an aggravation of their symptoms while at work and an improvement when away, which implies that they may be suffering from Occupational Asthma. Thus, when an individual’s Asthma is caused, not aggravated, by workplace materials, it is defined as Occupational Asthma. In the USA, OA is considered the most common occupational lung disease. At present, over 400 workplace substances have been identified as having asthmagenic or allergenic properties. Their existence and magnitude vary from region to region and the type of industry and can be as varied as wood dust (cedar, ebony, etc.), persulfates (Hairsprays), zinc or even seafood like prawns. For example, in France the industries most affected in order of importance are Bakeries and cake-shops, automobile industry and hairdressers, whereas in Canada the principal cause is wood dust, followed by isocyanates.

SIGNS & SYMPTOMS

Less than five years of exposure to an occupational agent can be enough for the appearance of the first OA symptoms. This depends on whether the reason for the OA to occur was exposure to the causative agent over a period of time (with a latency period) or a single exposure to an irritant but at a very high concentration (without latency period). Both eventually result in OA. Coughing, wheezing, nasal irritation, difficulty in breathing, tightness of chest are the most common symptoms and can be recognized more easily by asking oneself the following questions:

1. Are any of the above symptoms recurrent/chronic?
2. Are they present at work?
3. Do they worsen towards the end of the work day and/or end of the week?
4. Does the employee/worker feel an improvement in his condition when away from work, on vacation or on weekends?

If these symptoms persist, the person is most likely suffering from OA. However, one must be aware that this could also be because the person is already suffering from asthma and his condition was simply aggravated by workplace irritants (Work-aggravated asthma). In this case, although he will suffer similar consequences as someone who is suffering from OA (loss of work, medical expenses, etc.), his disease cannot be considered as having an occupational origin.

PREVENTION & TREATMENT

According to the Canadian Centre for Occupational Health and Safety (CCOHS) better education of workers, management, unions and medical professionals is the key to the prevention of OA. This will enable them to identify the risk factors and put in place preventive measures like masks or exposure limits, etc.

Recovery is directly dependent on the duration and level of exposure to the causative agent. Depending on the severity of the case, the condition of the patient can improve dramatically during the first year after removal from exposure.

Three basic types of procedures are used for treating the affected workers:

1) Reducing exposure

This method is most effective for those affected by irritant-induced OA. Thus, by reducing their exposure duration and level to the causative agent, the probability of suffering another reaction is lowered. But exposure can be reduced in other ways like making use of face masks or providing better ventilation. Now, more and more di-isocyanate free spray paints are available. Similarly, most hospitals and healthcare companies have exchanged latex gloves for other materials. Thus, reducing exposure to known asthmagens can also be used as a preventive measure.

2) Removal from exposure

Persons affected by OA that occurred after a latency period, whether a few months or years, must be immediately removed from exposure to the causative agent. This is their only chance of recovery. However, this entails severe socio-economic consequences for the worker as well as the employer due to loss of job, unemployment, compensation issues, quasi-permanent medical expenditures, hiring and re-training of new personnel, etc. Also, according to recent research the probability that those who suffer from OA remain unemployed longer than those who suffer from non-occupational asthma is higher. One solution to this problem is relocating the employee in the same company away from the causative agents.

3) Medical and pharmacological treatment

Anyone diagnosed with Asthma will have to undergo medical treatment. This is complementary to either removing or reducing the patient’s exposure to the causal agents. Two types of medication can be used:

• Relievers or bronchodilators

• Short-acting beta-agonists like salbutamol or terbutaline or long-acting beta-agonists like salmeterol and formoterol or anticholinergic, etc. dilate airways which relieve the symptoms thus reducing the severity of the reaction. Some patients also use it just before work to avoid a drop in the FEV¹.

• Preventers
• Anti-inflammatory agents like corticosteroids, LKTRA or mast cell stabilizers can be used depending on the severity of the case.