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Résumé La paralysie faciale périphérique a frigore ou idiopathique, dite encore de paralysie de Charles Bell chez les anglo-saxons, représente plus de la moitié des causes de paralysies faciales périphériques de l'adulte. S'il s'agit d'une pathologie dite bénigne, son retentissement fonctionnel et psychologique peut être important. L'hypothèse physiopathologique principale est celle d'une réactivation du virus HSV-1 dans le ganglion géniculé à l'origine d'un œdème du nerf facial et sa compression dans l'aqueduc de Fallope, canal osseux inextensible. La symptomatologie, un déficit moteur d'intensité variable intéressant les muscles faciaux ipsilatéraux des territoires supérieur et inférieur, cesse de progresser le plus souvent en moins de 24 heures et toujours en moins de trois jours. Fréquemment, elle est précédée ou accompagnée de douleurs rétro-auriculaires et/ou de sensation d'engourdissement de l'hémiface concernée. Le diagnostic est clinique et s'appliquera à éliminer les diagnostics différentiels représentés par les paralysies faciales de cause centrale ou périphérique secondaire (infections, néoplasies, pathologies auto-immunes). Dans les trois-quarts des cas, l'évolution est spontanément satisfaisante avec une récupération complète. Une corticothérapie orale de courte durée instaurée précocement (dans les 72 heures) améliore encore les taux de récupération complète, alors que l'intérêt de l'associer à un traitement antiviral n'est pas démontré. Des spasmes hémifaciaux (contractions involontaires des muscles de l'hémiface) ou des syncinésies (contractions involontaires accompagnant une contraction volontaire en lien avec un phénomène de réinnervation aberrante) peuvent émailler son évolution. L'électroneuromyographie peut montrer le bloc de conduction, la perte axonale, puis la réinnervation, et aider au diagnostic des complications. Abstract Idiopathic peripheral facial palsy, also named Bell's palsy, is the most common cause of peripheral facial palsy in adults. Although it is considered as a benign condition, its social and psychological impact can be dramatic, especially in the case of incomplete recovery. The main pathophysiological hypothesis is the reactivation of HSV 1 virus in the geniculate ganglia, leading to nerve edema and its compression through the petrosal bone. Patients experience an acute (less than 24 hours) motor deficit involving ipsilateral muscles of the upper and lower face and reaching its peak within the first three days. Frequently, symptoms are preceded or accompanied by retro-auricular pain and/or ipsilateral face numbness. Diagnosis is usually clinical but one should look for negative signs to eliminate central facial palsy or peripheral facial palsy secondary to infectious, neoplastic or autoimmune diseases. About 75% of the patients will experience spontaneous full recovery, this rate can be improved with oral corticotherapy when introduced within the first 72 hours. To date, no benefit has been demonstrated by adding an antiviral treatment. Hemifacial spasms (involuntary muscles contractions of the hemiface) or syncinesia (involuntary muscles contractions elicited by voluntary ones, due to aberrant reinnervation) may complicate the disease's course. Electroneuromyography can be useful at different stages: it can first reveal the early conduction bloc, then estimate the axonal loss, then bring evidence of the reinnervation process and, lastly, help for the diagnosis of complications. [ABSTRACT FROM AUTHOR]

Abstract: Purposes. – Neuropathies are defined as dysfunction of peripheral nerves, which may show motor, sensory and autonomic symptoms. Although most neuropathies are symmetric, it is important to distinguish a polyneuropathy from a mononeuropathy, a multiple mononeuropathy or a polyradiculoneuropathy. Electrophysiological procedures are helpful in determining the pathological process which may be either an axonopathy, a myelinopathy or a neuronopathy. Main points. – Major progresses have been made in the ten past years in the management and diagnostic approaches of peripheral neuropathy. The history and the physical examination are the first steps to the evaluation of patients with peripheral neuropathy. Electrodiagnostic studies and then laboratory tests are the next step in the diagnostic procedures of peripheral neuropathies. These will lead to a proper identification of the cause of neuropathy, allowing to develop a specific treatment for the patient. However, even after a careful work-up of a patient with neuropathy, 25 to 40% of patients with polyneuropathies remain undiagnosed. Perspectives. – Further development are focused in better understanding the pathogenesis and molecular mechanisms of peripheral nerve diseases in order to provide a specific and adequate treatment for each neuropathy. [Copyright &y& Elsevier]