Toxic encephalopathy.

Neurotoxic exposures are common. Although there are myriad substances that can cause encephalopathy, this review focuses on common environmental neurotoxins, such as select heavy metals, organic industrial toxins, and pesticides. The central nervous system is susceptible to toxic injury, and many environmental neurotoxins are capable of causing encephalopathy. When a patient presents with toxic encephalopathy, the differential diagnosis is initially broad. The clinical presentation after exposure to a toxin varies in severity among patients. Arriving at the correct diagnosis is often a diagnostic challenge. The importance of taking a good history and performing a comprehensive examination cannot be overemphasized. Neuroimaging and neurophysiologic testing typically play ancillary roles. Confirmatory laboratory testing is available for some toxins. Treatment of most toxic encephalopathies is not supported by clinical trials; additional research is needed in the field.