Management
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1. Remove the patient from exposure
After discussion with the patient, the medical practitioner should write a motivating letter to have the person moved to a job which does not involve exposure. This is in practice often difficult, as alternative work may not be readily available, and the risk of job loss is genuine. However, the longer the exposure the poorer the prognosis.
2. Treat the asthma
3. Submit a claim for worker’s compensation
Table 5.
Procedure for submitting a case of occupational asthma under the COIDA.
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| 1. | Complete First Medical Report (WCl 22)* and send to employer . | |
| 2. | Counsel patient about the need to avoid exposure and recommend to have him/her moved to another job. | ||
| 3. | Collate all investigations (serial PEFR, spirometry and allergy tests), including a chest x-ray and specialist opinions. Complete summary Medical History Form (WCl 111)*. Include detailed and chronological description of past and present jobs, exposures and processes. The recognised sensitising agent (as it appears on Schedule 3) must be clearly stated. Assess the degree of lung function impairment, whether temporary and/or permanent, and the nature of treatment required. Send to employer or Compensation Commissioner. | ||
| 4. | Complete Progress Medical Report (WCl 26)* at each subsequent visit, and send to employer or Compensation Commissioner. | ||
| 5. | Complete Final Medical Report (WCl 26)* at the final visit indicating the degree of permanent lung function impairment as well as the nature of treatment required. Send to employer or Compensation Commissioner. |
* These forms are obtainable from the Department of Labour
The process of submitting a compensation claim confers the following benefits to workers should the claim be accepted:
- temporary disablement benefits viz. 75% of wages is paid for the period during which the worker is absent from work (provided this exceeds 3 days)
- medical expenses for treatment of the asthma
- permanent disablement benefits once the case is finalised after a period of two years according to the criteria mentioned in Table 4. The compensation payment is based on the percentage permanent disability and the wages of the worker. It takes the form of a lump sum payment if the percentage disability is below 30% and a monthly pension if it is more than 30%.
4. Notify the case to the Chief Inspector
*The diagnosis of an occupational disease implies that a hazard to other workers may exist, which requires investigation and action. Medical practitioners are required by the OHSA to notify all cases of suspected occupational disease to the Chief Inspector, Department of Labour (Fax: 012-309 4382). This should also be done through form WCl 22 (see section 3 above).
* The case should also be reported to the voluntary Surveillance of Work-related and Occupational Respiratory Disease (SORDSA) register (Tel/Fax: 011-725 5978).
5. Prevention of chronicity and complications
*Engineering controls: Central to management of allergic disease is avoidance of the sensitising agent. The first line of such prevention should always be substitution of the hazardous agent, ventilation extraction or some other means of reducing exposure to the agent in question. This also means decreasing the risk of sensitisation of other, as yet unaffected, workers. Contact with the workplace occupational health service, if one exists, or with the employer is necessary if the diagnosis of the case is to have an impact on control measures.
* Administrative controls: The optimal solution for the sensitised worker would be a different job without exposure to the agent at the same terms of employment. In many cases this may not be possible, and such workers may have to choose between continue working while taking anti-asthma medication or to leave their jobs.
* Respirators: Should the abovementioned option not be possible, respirators in such situations may reduce gross exposure, but are unlikely to prevent the levels that may trigger attacks in sensitised subjects. In addition, respirators may increase the work of breathing and aggravate subjective sensations of air hunger.
*Prophylactic medication: Some form of preventive medication may be necessary to block the allergic or inflammatory response. In this regard, disodium cromoglycate has been shown to inhibit both the immediate and late response in conditions such as baker’s asthma. Beclomethasone dipropionate, in contrast, seems to inhibit mainly the late response. Medication should be adjusted along the usual lines based on clinical response.
*Education and training: Workers need to be informed and educated about the health effects of the hazardous agents to which they are exposed so that they may take the necessary precautions when working with these agents. This responsibility is entrusted to the employer under OHSA legislation, who should make use of the expertise of an occupational medical practitioner.
Prognosis
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* In the case of the worker who returns to the same job (or exposure) on anti-asthma medication prognosis will depend on whether exposure can be substantially reduced; on the agent in question; and on the severity of the clinical response.
*For some compounds such as TDI and platinum salts, only small amounts are believed to trigger severe attacks in sensitive persons. Even without dire or severe acute effects, continued exposure to the allergen is likely to result in aggravation of non-specific bronchial responsiveness, generalisation of the asthmatic response to stimuli beyond the workplace and ultimate irreversibility of the asthma even were exposure to cease.
* The case should also be reported to the voluntary Surveillance of Work-related and Occupational Respiratory Disease (SORDSA) register (Tel/Fax: 011-725 5978).
*Longitudinal studies of workers where the causative agent has been removed show the mean time to the plateau of improvement for pulmonary function after removal from exposure to be two years.
* Poor prognostic features identified in workers after removal from exposure include:
1. Longer duration of symptoms before diagnosis
2. Longer period of exposure before the development of symptoms
3. Significant non-specific bronchial responsiveness at presentation
4. Low baseline FEV1 (initial lung function)
*Even with no further exposure, the prognosis is therefore uncertain, with a number of studies demonstrating permanent effects. The continuing medical costs of even moderate asthma may thus be substantial. At present the COIDA makes provision for paying medical expenses for only 24 months at which point the patient should be assessed for permanent disability. Our experience suggests that should the patient require further treatment, the claim would have to be re-opened for another 24 months following the procedures contained in Table 5.
*Some studies have suggested that while removal from exposure may be beneficial in terms of symptoms and lung function, it is inevitably associated with loss of income. It would therefore be preferable for compensation to be directed towards assisting relocation and retraining rather than providing inadequate compensation for disability, which is difficult to assess in asthmatics.
References
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1. American College of Chest Physicians. Consensus statement. Assessment of asthma in the workplace. Chest (1995);108:1084-117.
2. Chan-Yeung M, Malo J-L. Aetiological agents in occupational asthma. Eur Respir J (1994);7:346-71.
3. Rees D, Panter C, Rautenbach B. Certification of occupational asthma and the submitting doctor (letter). SAMJ (1993);83:916.
4. American Thoracic Society. Guidelines for the evaluation of impairment/disability in patients with asthma. Am Rev Resp Dis (1993);147:1056-1061.
5. Rautenbach B. Permanent disability assessment in occupational diseases. Office of the Compensation Commissioner, Pretoria. Occupational Health Southern Africa (1996); 2:30-31
6. Malo J-L, et al. Patterns of improvement of spirometry, BHR and IgE antibody levels in Occupational asthma. Am Rev Respir Dis (1988); 138:807-12.
7. Gannon PFG, Weir DC, Robertson AS. Health employment, and financial outcome in workers with occupational asthma. Br J Ind Med (1993);50:491-496.
Appendices
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Appendix 1. Referral centres for occupational asthma
Cape Town
WorkHealth Occupational Diseases Clinic, Groote Schuur Hospital (021) 404 4369
Workers’ Clinic (021) 47 8043 or 650 3508
Johannesburg
National Centre for Occupational Health (011) 720 5734
Durban
Workers’ Health Centre (031) 258 115
Occupational Medicine Clinic, King Edward Hospital (031) 25 8115 or 260 4287
Appendix 2. List of RAST available for investigating occupational agents
- Isocyanates: TDI, MDI, HDI
- Grain: Wheat, rye
- Enzymes: Alpha-amylase
- Storage mites:
- Mahogany wood
- Pthallic anhydride
- Formaldehyde/Formalin
- Ethylene oxide
- Latex, Hevea braziliensis
- Trimellitic Anhydride (TMA)
- Laboratory animals:
* Note: Other RAST can be developed by the Allergology Unit, UCT Medical School, depending on demand and availability of methods in the literature (021) 406 6147. See also Appendix in Manual on Available RAST Tests (Pharmacia immunoCAP RAST): occupational allergens.
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