Respiratory pathology in vibroacoustic disease: 25 years of research

Respiratory pathology induced by low frequency noise (LFN, < 500 Hz, including infrasound) is not a novel subject given that in the 1960's, within the context of U.S. and U.S.S.R. Space Programs, other authors have already reported its existence. Within the scope of vibroacoustic disease (VAD), a whole-body pathology caused by excessive exposure to LFN, respiratory pathology takes on specific features. Initially, respiratory pathology was not considered a con- sequence of LFN exposure; but today, LFN can be regarded as a major agent of disease that targets the respiratory system. The goal of this report is to put forth what is known to date on the clinical signs of respiratory pathology seen in VAD patients.

Data from the past 25 years of research will be taken together and presented.

In persons exposed to LFN on the job, respiratory complaints appear af- ter the first 4 years of professional activity. At this stage, they disappear during vacation periods or when the person is removed form his /her workstation for other reasons. With long-term exposure, more serious situations can arise, such as, atypical pleural effusion, respiratory insufficiency, fibrosis and tumours. There is no correlation with smoking habits. In LFN-exposed animal models, morphological changes of the pleura, and loss of the phagocytic ability of pleural mesothelial cells (explaining the atypical pleural effusions). Fibrotic lesions and neo-vascularization were observed along the entire respiratory tract. Fibrosis lesions and neovascularisation were observed through- out the respiratory tract of the animals seen. Pre-malignant lesions, metaplasia e displasia, were also identified.

LFN is an agent of disease and the respiratory tract is one of its preferential targets. The respiratory pathology associated with VAD needs further in-depth studies in order to achieve a greater understanding, and develop methods of pharmaco- logical intervention.