BACKGROUND AND METHODS: Mass @entity221 may be difficult to differentiate from illness caused by bioterrorism, rapidly spreading infection, or toxic substances. We investigated symptoms attributed to exposure to toxic gas at a high school in Tennessee. In November 1998, a teacher noticed a 'gasoline-like' smell in her classroom, and soon thereafter she had a @entity10 , @entity390 , @entity1353 , and @entity1296 . The school was evacuated, and 80 students and 19 staff members went to the emergency room at the local hospital; 38 @entity1 were hospitalized overnight. Five days later, after the school had reopened, another 71 @entity1 went to the emergency room. An extensive investigation was performed by several government agencies. RESULTS: We were unable to find a medical or environmental explanation for the reported illnesses. The @entity1 who reported symptoms on the first day came from 36 classrooms scattered throughout the school. The most frequent symptoms (in this group and the group of @entity1 who reported symptoms five days later) were @entity10 , @entity1296 , @entity390 , and drowsiness. Blood and urine specimens showed no evidence of @entity1223 , volatile organic compounds, pesticides, @entity3215 , @entity6453 , or @entity349 . There was no evidence of toxic compounds in the environment. A questionnaire administered a month later showed that the reported symptoms were significantly associated with female sex, seeing another ill @entity1 , knowing that a classmate was ill, and reporting an unusual odor at the school. CONCLUSIONS: The illness attributed to toxic exposure had features of mass @entity221 - notably, widespread subjective symptoms thought to be associated with environmental exposure to a toxic substance in the absence of objective evidence of an environmental cause. Alleviation of the @entity148 surrounding an episode of mass @entity221 requires prompt recognition and a detailed investigation.

Mass XXXX attributed to toxic exposure at a high school.

@entity1 :: ('9606', 'Species') :: ['people', 'person', 'persons'] @entity6453 :: ('MESH:D010269', 'Chemical') :: ['paraquat'] @entity390 :: ('MESH:D009325', 'Disease') :: ['nausea'] @entity1223 :: ('MESH:D002248', 'Chemical') :: ['carbon monoxide'] @entity1353 :: ('MESH:D004417', 'Disease') :: ['shortness of breath'] @entity349 :: ('MESH:D008628', 'Chemical') :: ['mercury'] @entity148 :: ('MESH:D001008', 'Disease') :: ['anxiety'] @entity3215 :: ('MESH:D011078', 'Chemical') :: ['polychlorinated biphenyls'] @entity1296 :: ('MESH:D004244', 'Disease') :: ['dizziness'] @entity10 :: ('MESH:D006261', 'Disease') :: ['headache'] @entity221 :: ('MESH:D005334', 'Disease') :: ['psychogenic illness']
@entity221 :: (MESH:D005334,Disease) :: ['psychogenic illness']
