Diagnosis of Asbestosis in Japan

                                                                                         MD. M.Med. OM Tran Anh Thanh,

                                                                                                         HEMA, MoH

            Exposure to asbestos induces asbestosis in lung parenchyma and pleural plaque, benign asbestos pleurisy or diffuse pleural thickening as non-neoplastic diseases, and lung cancer or mesothelioma as neoplastic diseases.

            In Japan we have established the compensation system for victims by occupational exposure since 1948, but the relief system for the victims by non-occupational exposure has not been established until 2006. In the former system, the objective diseases include asbestosis, benign asbestos pleurisy, diffuse pleural thickening, lung cancer and mesothelioma, while in the latter system those include lung cancer and mesothelioma at the start and in this year, asbestosis and diffuse pleural thickening have been added.

            Diagnosis of Asbestosis in Japanis summarized and showed as below:

1) Occupational asbestos exposure

2) Irregular opacities in the lower lung field in chest X-ray

3) Impairment of lung capacity by pulmonary function test

4) Fine crackle audible in the lower lung field at inhalation

5) Elimination of other similar diseases and excepting asbestos induced diseases

            Asbestosis usually induced by high dense asbestos exposure. Therefore, minute occupational histories and HRCT examinations are essential.

            Difficulties in Asbestosis diagnosis in Japan:

1) There are some cases of asbestosis who can not be differentiated from idiopathic interstitial  pneumonia

2) A cases of Interstitial pneumonia with pleural plaques is not always asbestosis

3) Asbestosis appeared by high dense asbestos exposure with more than 25 fibers/mL・year.

4) The pathological findings (lung fibrosis with more than  2 asbestos bodies/cm²) are not always consistent with the radiological findings.

5) From the ILO classification, profusion rates of more than 1/1 are diagnosed asbestosis, but some radiologists diagnosed asbestosis by the findings of CT scanning.

            Therefore, Asbestosis cases in Japanwith failure in lung function test and compilation with other pneumoconiosis are compensated.