Social and economic impact of neurotoxicity in hazardous waste workers in Lenoir, North Carolina.

A detailed study of workers at a hazardous waste incinerator in Lenoir, North Carolina, revealed significant financial losses resulting from health problems caused by the incinerator. The losses included approximately $3 million for 3 years of medical care for 28 workers employed at the incinerator. Future wage losses for exposed workers were projected to be from $14 million to $15 million. Loss of the incinerator as a viable employment base was a significant blow to the local economy. Third-party payers of medical costs, government and private, were also at risk of financial loss. Workers' compensation benefits ranging from $6500 to $274,000 per person were paid by insurance companies to some workers; however, these benefits did not always cover the medical expenses incurred. As a result of their illnesses, 11 of the 28 workers (39%) had to sell or give up their homes, 8 workers (36%) lost their vehicles, 19 workers (68%) began to receive Social Security Disability payments, and 11 workers (39%) obtained food stamps. One worker not included in these figures died 3 years after he settled with the state workers' compensation program. Five of the 28 interviewed workers continue to work in spite of continuing health problems. The 23 workers who cannot work will have estimated lifetime medical expenses of $25.4 million.

Evaluation of chronic neurological sequelae after acute pesticide exposure using SPECT brain scans.

A case in which SPECT brain imaging was used in the diagnosis and treatment of chronic effects from acute acetylcholinesterase inhibitor poisoning is presented. The patient was exposed to an insecticide mixture containing phosphorothiate, pyrethrin, piperonyl butoxide, and petroleum distillates, which produced symptoms consistent with acute acetylcholinesterase inhibitor poisoning as well as an upper respiratory tract irritant. Delayed sequelae of gross neurologic symptoms followed, that is, coarse tremor, intermittent hemiballistic movements of the right arm and leg, flaccid muscular tone, fasciculations of muscle groups, muscle cramps, and sensory disturbances. A brain single-photon emission computerized tomography (SPECT) scan was performed 34 mo postexposure, revealing significantly decreased blood flow to the left temporal lobe and to the right and left basal ganglia. The patient's paresthesias were treated with phenytoin, which resulted in worsening of her movement disorder. A trial of amantadine and selegiline (Deprenyl) resulted in a dramatic reduction in dysfunctional movements and ataxia. Post amantadine and selegiline therapy, brain SPECT images revealed significantly improved blood flow with minimally decreased blood flow to the right and left basal ganglia. The use of SPECT scan techniques helped to elucidate objective chronic central nervous system effects subsequent to an acute insecticide exposure and also assisted in the evaluation of the effectiveness of therapeutic intervention.

Three-dimensional brain metabolic imaging in patients with toxic encephalopathy.

Thirty-three workers, ages 24 to 63, developed clinical toxic encephalopathy after exposure to neurotoxins and were studied by SPECT brain scans. Five were exposed to pesticides, 13 were acutely exposed to mixtures of solvents, 8 were chronically exposed to mixtures of hazardous wastes that contained organic solvents, 2 were acutely exposed to phosgene and other toxins, and 5 had exposures to hydrogen sulfide. Twenty-nine had neuropsychological testing and all had a medical history and physical. Of the workers who had a clinical diagnosis of toxic encephalopathy, 31 (93.9%) had abnormal SPECT brain scans with the most frequent areas of abnormality being temporal lobes (67.7%), frontal lobes (61.3%), basal ganglia (45.2%), thalamus (29.0%), parietal lobes (12.9%), motorstrip (9.68%), cerebral hemisphere (6.45%), occipital lobes (3.23%), and caudate nucleus (3.23%). Twenty-three out of 29 (79.3%) neuropsychological evaluations were abnormal. Other modalities when performed included the following percentages of abnormals: NCV, 33.3%; CPT sensory nerve testing, 91.3%; vestibular function testing, 71.4%; olfactory testing, 89.2%; sleep EEG analysis, 85.7%; EEG, 8.33%; CT, 7.14%; and MRI brain scans, 28.6%. The complex of symptoms seen in toxic encephalopathy implies dysfunction involving several CNS regions. This series of patients adds to the previous experience of brain metabolic imaging and demonstrates that certain areas of the brain are typically affected despite differences in toxin structure, that these lesions can be globally defined by SPECT/PET brain scans, that these lesion correlate well with clinical and neuropsychological testing, and that such testing is a useful adjunct to previous methods. EEG and structural brain imaging such as CT and MRI are observed to have poor sensitivity in this type of patient. Additional metabolic imaging studies need to be done to explore dose, time, and specific toxin effects as well as mechanisms of toxicity and olfactory migration.