RT Book, Section A1 Amato, Anthony A. A1 Barohn, Richard J. A2 Kasper, Dennis A2 Fauci, Anthony A2 Hauser, Stephen A2 Longo, Dan A2 Jameson, J. Larry A2 Loscalzo, Joseph SR Print(0) ID 1138108436 T1 Peripheral Neuropathy T2 Harrison's Principles of Internal Medicine, 19e YR 2014 FD 2014 PB McGraw-Hill Education PP New York, NY SN 9780071802154 LK accesspharmacy.mhmedical.com/content.aspx?aid=1138108436 RD 2019/12/06 AB Peripheral nerves are composed of sensory, motor, and autonomic elements. Diseases can affect the cell body of a neuron or its peripheral processes, namely the axons or the encasing myelin sheaths. Most peripheral nerves are mixed and contain sensory and motor as well as autonomic fibers. Nerves can be subdivided into three major classes: large myelinated, small myelinated, and small unmyelinated. Motor axons are usually large myelinated fibers that conduct rapidly (approximately 50 m/s). Sensory fibers may be any of the three types. Large-diameter sensory fibers conduct proprioception and vibratory sensation to the brain, while the smaller-diameter myelinated and unmyelinated fibers transmit pain and temperature sensation. Autonomic nerves are also small in diameter. Thus, peripheral neuropathies can impair sensory, motor, or autonomic function, either singly or in combination. Peripheral neuropathies are further classified into those that primarily affect the cell body (e.g., neuronopathy or ganglionopathy), myelin (myelinopathy), and the axon (axonopathy). These different classes of peripheral neuropathies have distinct clinical and electrophysiologic features. This chapter discusses the clinical approach to a patient suspected of having a peripheral neuropathy, as well as specific neuropathies, including hereditary and acquired neuropathies. The inflammatory neuropathies are discussed in Chap. 460.