Multiple Chemical Sensitivity: an Unusual Case of Vocal Disorder

Abstract

RATIONALE: Multiple Chemical Sensitivity (MCS) is a phenomenon observed in patients who reported sensitivities involving any and every organ system, following exposure to environmental agents including pesticides, solvents, and others. A 39-year-old white man was accidentally exposed to an extremely high concentration of petroleum aromatic hydrocarbons (AH) vapors at his job. Since that time he developed voice disorder attacks every time he smelt gasoline or other HC vapors. These episodes delayed about one hour, and occurred at the work environment, at home or at the gas station. He had no previous history of allergy or vocal cord dysfunction. Investigational procedures for gastro-esophageal reflux and a video-laryngoscopy did not show abnormalities. METHODS: Double blind challenge tests were performed with 5 different chemical compounds supplied by the employer. He was exposed to inhalation for one minute and the results were evaluated for the occurrence of voice disorder and accompanied by video-laryngoscopy. RESULTS: Voice disorder associated with vocal cord edema was observed immediately after provocation with samples 1, 2 and 4. They were composed by a mixture of nafta derivates (ND) and at least 15% of AH. Samples 3 and 5 did not produce voice disorder or anatomic modifications on the vocal cords. They were composed by NH4OH plus Na2S, and ND plus 10% of AH, respectively. CONCLUSIONS: These results showed evidences that AH could be involved in the observed events. The voice disorders were well correlated with video-laryngoscopy findings. AH could be listed as a potential agent involved in MCS.