[What is a peripheral neuropathy?].

Peripheral neuropathies may be classified according to the localisation of symptoms and signs. This step necessitates a good knowledge of the peripheral nervous system anatomy. The diagnostic strategy relies on this classification and allows, thanks to the neurophysiological exam to establish the pathogenic mechanism of the neuropathy. These data are important to limit the possible aetiologies to a reasonable number in order to use the appropriate paraclinical work-up. Laboratory examinations may be simple or sophisticated and their use may require the help of an expert center. In a limited number of cases, nerve biopsy is still a very useful tool to determinate the mechanism of peripheral neuropathy and to guide the treatment.