REACTIVE AIRWAYS DYSFUNCTION SYNDROME AND TOXIC ASTHMA

The recently identified Brooks syndrome or RADS is an authentic form o f asthma only induced by acute inhalation of high concentrations of ir ritant gas, smoke, or vapour. Its integration into the occupational ca tegory of the asthma classification is still a subject of debate. Anal ysis of three clinical cases illustrates the main features of this syn drome. Two of these cases involved substances which had not been previ ously reported in this disease: ethylene oxide and an organophos phoru s insecticide, dichlorvos. A review of the literature demonstrates the multiplicity of published cases and the increasing number of recogniz ed aetiological agents of RADS. The proposed pathophysiological mechan isms directly incriminate the action of the irritant substance on the bronchial epithelium. The frequency of RADS after acute irritant inhal ation is unknown and the presence of prognostic factors has yet to be determined, emphasizing the need for early and prolonged respiratory m onitoring of exposed subjects. There appears to be a recent increase i n the prevalence of asthma in the general population Environmental che mical pollutants are partly responsible when they induce RADS or a ''i rritant asthma'' following repeated exposure to moderate doses of toxi c gases.