Neuropathic Disorders by K. G. Braund; B0241.0203

Neuropathic Disorders The peripheral nervous system (PNS) comprises the cranial nerves, spinal nerve roots, dorsal root ganglia, the peripheral nerve trunks (motor and sensory nerves), the terminal branchings of motor nerves as they innervate skeletal muscle, and the peripheral autonomic system [1]. Disorders of the parent cell bodies located in the spinal cord (and/or brainstem) are discussed under motor neuron diseases. In people, dorsal root ganglion degenerations are described as sensory neuropathies, while in animals such disorders are sometimes called ganglionopathies or sensory neuronopathies. In the chapter on Localization, I have arbitrarily classified small animal neuropathies into hereditary/degenerative and developmental disorders, and acquired toxic, traumatic, metabolic, inflammatory/infectious, neoplastic/paraneoplastic, and vascular disorders (see neuropathic syndrome). Peripheral nerve disorders are common and usually well-recognized in dogs and cats, although in some instances problems may arise in distinguishing neuropathies from diffuse muscle disease, certain CNS disorders, or skeletal problems. In general, most acquired neuropathies are seen in both dogs and cats, although hereditary disorders are more commonly reported in dogs. Both sophisticated electrodiagnostic testing and qualitative/quantitative pathological studies have further defined peripheral nerve disease in small animals. Despite these advances, the etiology of many neuropathies in dogs and cats continues to be uncertain, in contrast with the situation in people, in whom approximately 10 to 15% of neuropathies remain cryptogenic [2].