Evaluating computed tomography and broncho alveolar lavage in early diagnosis of pulmonary asbestosis

Forty-eight male asbestos workers were studied with clinical interrogation and examination, chest radiograph, lung function, body box studies, blood gases at rest and after exercise, BAL and in 40 cases by CT scan. Mean age was 40:1 (+/- 5.2) and work exposure 18.1 (+/- 4.0) years. There were 52% smokers. We found rales in 93%. Lung functions and clinical picture were not related to smoking (FEV1 was lower). There was evidence of airway obstruction by FEV1/FVC% (58% as below 80%), bronchodilator improvement (18% as over 10%), Raw (45% as over 2 cm H2O/l/sec) or RV/TLC% (39.5% as above 40%). Arterial pO2 decreased (over 2 mm) on exercise in 18%. By ILO classification chest radiographs were up to 1/1 in 10 (21%) and 2/2 or above in 19 (40%). Pleural abnormalities were seen by X-ray in 20 (42%) and by CT Scan in 26 (54%). The scan was abnormal in 92%. Lung function was not related to radiographic ILO grading but was lower with abnormal CT scan. BAL revealed normal (or low) cell counts, fewer macrophages (35%) and more polymorphs (23%) and lymphocytes (29%) over values for controls reported earlier (8); only 9 (19%) showed high cell counts. Asbestos body count was high (28.4) and was unrelated to other abnormalities. In some departments asbestos (respirable) fibre load was high (mean 0.61 to 3.12: maximum 0.84 to 6.78). It is concluded that in a proportion, early asbestosis can be diagnosed by CT scanning and high asbestos body count in BAL.