Participação das vias aéreas centrais na doença vibroacústica Involvement of central airways in vibroacoustic disease patients

No abstract

Epidemiological studies indicate that squamous cell carcinomas account for approximately 40% of all lung tumours in men. It seems to be highly relevant that all VAD patient respiratory tract tumours are squamous cell carcinomas. It is not surprising that helicopter pilots are the ones who are affected the earliest because previous studies have shown that helicopter pilots exhibited the highest values for the frequency of sister chromatid exchanges. Generally, epidemiological tumor studies do not take histological tumor type into account, but given the results herein, it would seem of the utmost importance to begin specifiying the exact histological type of tumor in all statistical studies.

In the involuntary response to increased PCO2 levels, central chemoreceptors are responsible for 70% of the ventilatory stimulus. In VAD patients, this dysfunction may originate in the brainstem. This is corroborated by the fact that VAD patients register abnormal values for auditory brainstem evoked potentials, and disclose lesions with magnetic resonance imaging. The neurological control of breathing is compromised in VAD patients. The P0.1 (CO2) index may be a useful clinical indicator for VAD diagnosis and follow-up.

Data is in accordance with what was observed in LFN-exposed animal models and also in 8 VAD patients who developed lung tumours. Collagen disruption and degeneration was also observed in electron microscopy images of the respiratory tract of LFN-exposed rodents. Thickened blood and lymphatic vessel walls have been consistently seen in images of VAD patients and of LFN-exposed rodents. During bronchoscopy performed by other reasons, this sort of structural aspects is not frequently seen. Taken together, it is strongly suggested that these findings could be VAD-specific.