Diagnosis of chronic neuropathy.

Chronic neuropathy is the most frequent condition affecting the peripheral nervous system. It includes symmetrical polyneuropathies, multifocal mononeuropathies, mononeuropathies and radiculopathies. Mononeuropathies are mainly due to compression or entrapment and are not discussed in this review, which focuses on polyneuropathies and multifocal mononeuropathies with a chronic course, lasting for more than 2 months. Their diagnosis requires a systematic approach including clinical, electrophysiological, biological, and sometimes pathological investigations. The search for an etiological diagnosis may involve a very wide panel of hereditary and acquired diseases. Despite progress in the understanding and diagnosis of many chronic neuropathies, some of them remain unresolved.