Peripheral neuropathy

In medicine, neuropathy is abnormal function of one or more nerves of the peripheral nervous system.

Classification

Mononeuropathy

Mononeuropathy is "disease or trauma involving a single peripheral nerve in isolation, or out of proportion to evidence of diffuse peripheral nerve dysfunction. mononeuropathy multiplex refers to a condition characterized by multiple isolated nerve injuries. Mononeuropathies may result from a wide variety of causes, including ischemia; traumatic injury; compression; connective tissue diseases; cumulative trauma disorders; and other conditions." Multiple mononeuropathies that occur at the same time are called mononeuropathy multiplex or mononeuritis multiplex.

Polyneuropathy

Polyneuropathies are "diseases of multiple peripheral nerves simultaneously. Polyneuropathies usually are characterized by symmetrical, bilateral distal motor and sensory impairment with a graded increase in severity distally. The pathological processes affecting peripheral nerves include degeneration of the axon, myelin or both. The various forms of polyneuropathy are categorized by the type of nerve affected (e.g., sensory, motor, or autonomic), by the distribution of nerve injury (e.g., distal vs. proximal), by nerve component primarily affected (e.g., demyelinating vs. axonal), by etiology, or by pattern of inheritance."

Axonal degeneration may be caused by diabetes, alcohol, uremia, or porphyria. These tend to affect longer axons. These show reduced amplitude on nerve conduction testing.

Demyelination may be caused by autoimmune diseases (such as Guillain-Barre syndrome) and hereditary neuropathies. These tend to affect motor axons. These show reduced velocity on nerve conduction testing.

Causes include chronic inflammatory polyradiculoneuropathy and neurpahty secondary to paraproteinemias.