Toxic neuropathy

Peripheral neuropathies caused by toxic agents are often misdiagnosed. To make the diagnosis of a toxic neuropathy, the physician must have a high index of clinical suspicion and pursue the history to identify the offending agent. In many cases, there is no specific diagnostic test, and diagnosis relies on the clinical and electrodiagnostic evaluation. Given the very large number of peripheral nerve toxins, it is not possible to review all of them, and this chapter focuses on the most common toxins that cause clinically relevant peripheral neuropathy. Characteristic features of each disorder as well as general principles of neurotoxicology are emphasized. The toxins are organized into three categories: occupational and environmental exposures, recreational substance abuse, and iatrogenic exposures. Historically, occupational and environmental exposures provided the greatest risk of toxic neuropathy. However, with improving work conditions and careful precautions, these have become less frequent. Currently, the principal source of toxic neuropathies is prescription medication. Because of the users’ socio-economic status, neuropathies from recreational substances have been more difficult to study in a systematic fashion.