Reactive airways dysfunction syndrome after exposure to dinitrogen tetroxide.

Abstract

Reactive airways dysfunction syndrome (RADS) is characterized by persistent bronchial hyperreactivity and asthmatic symptoms in a previously healthy individual after a single intense exposure to an irritant fume, vapor, or gas. On October 23, 1995, a cloud of dinitrogen tetroxide (N2O4) escaped from a railroad tanker car in Bogalusa, Louisiana, exposing an estimated 4,000 citizens to the gas. A sample of 234 patients with respiratory complaints after the spill received a complete history and physical examination, a symptom questionnaire, and pulmonary function tests. Patients whose previously undocumented asthma-like symptoms persisted for 3 months after exposure to N2O4 had methacholine challenge testing. Of the 234 patients evaluated, six met the criteria for a diagnosis of RADS. The distance of these six patients from the source of the leak, their durations of exposure, and initial symptoms were not different from those of the sample patients who did not have RADS. After evaluation of 234 symptomatic patients who were exposed to N2O4, we diagnosed six cases of RADS. There were no demographic characteristics or initial symptoms that identified patients who were at risk of having this syndrome. We believe we are the first to report cases of RADS due to N2O4 exposure.