[Polyneuropathy: diagnosis and treatment]

Polyneuropathy is a common disorder with heterogenic clinical presentation and many possible etiologies. This review presents diagnostic clues for physicians and neurologists without specialist competence in neuromuscular disorders. Diagnostic procedure of polyneuropathy include cerebrospinal fluid examination, electrophysiological examinations, and sural nerve biopsy. Although pathologic examinations using biopsied sural nerve rarely reach specific diagnosis and are recently seem to be underestimated, careful scrutiny of the morphology of each myelinated nerve fiber as well as evaluation of clinical/pathological correlation may be powerful tools to reach proper diagnosis. Polyneuropathy presents symmetric motor and sensory impairment with "gloves and stockings" distribution. This characteristic clinical presentation is based on two different types of pathophysiology. One, neuronal malfunction which leads to inability in keeping homeostasis of axonal endings; the other, the "sum" of scattered focal lesions throughout the peripheral nervous system: longer axons have more chances to get local injuries. The former pathomechanism is shared by most of hereditary neuropathies and toxic neuropathies, and the latter includes inflammatory neuropathies as well as some vasculitic neuropathy, and possibly, diabetic neuropathy. Hence, we should keep in mind that the exact lesion site does not necessarily present at sural nerve, especially in inflammatory neuropathies and vasculitic neuropathies.