[Diagnostic approach]

Multiple mononeuropathies and peripheral polyneuropathies are due to a large variety of causes, and they frequently raise difficult diagnostic problems. Clinical examination has lost nothing of its value, but electrophysiological techniques and, in some cases, neuromuscular biopsy provide a better approach to the diagnosis of peripheral neuropathies. These neuropathies can now be classified according to their acute, subacute or chronic course and to the axonal or demyelinating nature of the physiopathological process involved.