الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Work related asthma is one of the most common morbidities in occupational field generally and one of the most respiratory diseases in occupational settings specifically at steel plants as declared recently by the World health Organization (WHO). WRA either occupational asthma (OA) or work exacerbated asthma (WEA) in its two pathophysiological types; sensitizers induced asthma (SIA) or irritants induced asthma (IIA) leads to partial/total, temporary/ permanent disabilities if misdiagnosis or even underdiagnosis occurred due to lacking of diagnostic standards by occupational physicians and chest specialists. The medical, psychological and social burden of this impairments and disabilities is very high and needs collaboration from all employers, employees, health organizations and all the concerned community.
In Iron and Steel industries, workers are exposed in the workplace to several chemical hazards including vapors, fumes and different dust particulates from continues melting, casting and rolling processes in addition to several physical hazards as changes in temperature. WRA is one of the most common respiratory diseases affecting the workers in different sections, so the present study selected 160 workers from Steel plant in Alexandria Governorate to investigate WRA among their workers. 80 workers were selected from administrative section and quality control section as (group I) of non-exposed workers in comparison to another 80 workers who were selected from steel melting section and rolling mill section as (group II) of exposed workers.
For proper diagnosis of WRA, all available tools should be utilized in stepwise approach to reach the precise diagnosis. It is primarily based on diagnosis of asthma first then relate the disease with work. This was achieved in this study by answering the main related questions by fully taken detailed asthma and occupational history, in which asthma symptoms (dyspnea, chest tightness, cough and wheezes) which vary in duration and intensity according to GINA guidelines, were increased with increase work durations, improve away from work at weekends or long vacations except for late irreversible stages and other co-workers were suffering from the same disease.
On the way to continue the diagnosis of asthma, full general and chest examination should be done, then higher steps should be taken by using physiological tests (PFT) for diagnosis of asthma severity and reversibility. FEV1 was measured and it was lower in exposed group (53.68%) versus (66.20%) in non-exposed workers, FVC was also lower in exposed group (88.78%) versus (92.20%) in non-exposed workers and finally FEV1/FVC ratio was lower in group II (59.68%) versus (70.36%) in group I.
Additional steps after spirometry should be followed, as for radiological imaging in which routine chest x-ray is not useful except in late complicated stages, but using HRCT enabled us to view more detailed airway and parenchymal pathological changes and estimated these changes as regard its reversibility. Bronchial wall thickening (BWT), bronchial dilatation and mucous impaction were reflecting airway changes, while mosaic pattern, emphysema, atelectasis and air trapping were the most important parenchymal pathological changes. For BWT, bronchial dilatation, atelectasis and air trapping were all statistically significant in exposed workers than non-exposed workers. Mucous impaction, mosaic pattern and emphysema were not statistically significant between both groups. However, generally the endpoint HRCT changes were higher in group II (93.8 %) versus (80%) in group I.
For evaluation of airway inflammation, serum biomarkers were another remarkable tool in asthma diagnosis and identifying its phenotypes. As regard eosinophilic or non-eosinophilic asthma phenotype, eosinophils percentage and levels of IgE were measured. IL-5 is cytokine representing T2-high endotype asthma, which has a key role in eosinophil differentiation, survival, activation, and migration into the lungs. For T2-low endotype, TNF-α is another proinflammatory cytokine which plays a major role in inflammation by inducing a general inflammatory response and facilitating the migration of eosinophils and neutrophils which leads to chronic inflammation and remodeling. All these biomarkers were significantly higher in exposed group II workers in comparison to non-exposed group I workers. In the current study severalpositive significant correlations were found between increasing the duration of work, increasing pathological changes by HRCT and increasing levels of all biomarkers. Interestingly, all these parameters were showing inverse correlation with PFT results.
According to the results of this study, it was proved that continuous exposure in the work place to different allergens is the main cause in exaggerated physiological, pathological and inflammatory changes in exposed workers when compared with non-exposed workers. Also, the current study is showing the importance of early detection of any pathological changes by radiological imaging HRCT specially BWT as proved by ROC curve, and inflammatory changes by measuring the level of some serum biomarkers in specific IL-5 as proved by ROC curve too, in addition to TNF-α beside the routinely used eosinophils, CRP and IgE.
Finally, highly effective preventive measures will not eliminate the occurrence of WRA, will not prohibit the disease chronicity and will not stop the disease progress to unwanted impairments or disabilities. Therefore, legal issues are hitting strongly industrial organizations and the cost in fact is very high, this cost is paid financially and economically from these organizations, and also, it is paid from workers in terms of illness, loss of job, low income and low socioeconomic standards. The only way to avoid these consequences is the use of newly effective investigations to detect the disease even in asymptomatic patients, HRCT and serum biomarkers are promising to achieve this goal, even with a little bit higher cost but the fact that the cost of health less than the cost of illness should be the basic concept in handling this worldwide problem.
Conclusions and recommendations
1. Work related asthma is a very common respiratory disease in occupational medicine but it is likely under-recognized by chest consultants. It is highly curable and preventive disease, so early recognition of aetiological factors, early diagnosis and management of the disease will reduce its morbidity.
2. The diagnosis of WRA is to be confirmed while the patient is still working, the diagnosis after leaving the suspected job is very hard. However, early removal from exposure to a sensitizer or irritant increases the chances of recovery.
3. In the present study most of clinical, physiological, pathological and inflammatory findings were more among the workers in steel melting section and rolling mill section with continuous exposure at the work place to different allergens, than non- exposed workers in quality control department and administrative department who were not exposed to any allergen in their work places.4. The diagnosis of WRA should be confirmed by objective tools, Pulmonary function tests are still one of the most important guiding tools for diagnosis and assessing the obstruction severity and reversibility. As more severe irreversible cases, or combined with restrictive elements will be highly recommended for medicolegal issues.
5. Imaging of airways by HRCT provides the great opportunity to extend the understanding of asthma heterogenicity. MDCT imaging has enabled us to study the large and small airways architecture in details and assess the parenchymal structure.
6. Pathological findings by HRCT were related with asthma severity and long-lasting disease but there are some asthmatics that also present early abnormalities, even in milder asymptomatic forms.7.This study found that bronchial wall thickening (BWT) as proved by ROC curve is significantly important as sensitive and specific parameter in diagnosis of WRA by HRCT. 8.Biomarkers are broadly available in asthma diagnosis; it is also associated with disease severity and prolonged duration of work.9.High levels of eosinophils, CRP, IgE, IL-5 and TNF-α were found in asthmatic participants with continuous exposure than non-exposure conditions and in mild asymptomatic cases. 10. IL-5 as proved by ROC curve is significantly important as sensitive and specific biomarker parameter in diagnosis of WRA.
11. HRCT and studied biomarkers (eosinophils, CRP, IgE, IL-5 and TNF- α) may contribute to the development of a scale that can more accurately assess temporary and permanent impairments or disabilities due to WRA. A scale based not only on physiological parameters (PFT) but also on information’s obtained from assessment of inflammation from HRCT and biomarkers.
12. Both HRCT and Serum biomarkers are recommended if possible, economically, to be used in routine investigations as periodic examinations of steel workers for early detection of the disease and early avoidance of any unwanted medicolegal issues. 13. Correct management of cases in early reversible stages is the main health and legal purpose to stop the disease progress and avoid expensive compensations.The relationships between HRCT indices and biomarkers of inflammation are an important area for additional investigations and further studies.