[Evaluation of the plasma endothelin levels in facial nerve paralysis]

The etiology of so-called Bell's palsy is still unknown. Based on the hypothesis that endothelin, with its potent vasoconstricting action, is in some way involved in the etiological mechanism of facial nerve paralysis, we measured the blood endothelin levels of 62 patients with Bell's palsy in the acute stage (within one week following onset). The measurements were extended to include 10 patients with Ramsay Hunt syndrome and 14 patients with zoster sine herpete. To determine endothelin content, blood samples were drawn into blood collecting tubes, containing EDTA-2Na+aprotinin at any time desired during the day. The samples were immediately chilled and centrifuged to separate the plasma portion, and 2ml of this plasma sample was preserved by freezing. ET-1 was extracted using silica-ODS and analyzed by RIA using anti-ET 1 antibody. An age-matched comparison between the Bell's palsy patients and 36 normal individuals using the Mann-Whitney U test showed a significant difference (p < 0.01). The patients with Ramsay Hunt syndrome and zoster sine herpete also tended to have elevated endothelin levels. This finding suggests that disorders of the microcirculatory system in which endothelin is in some way involved may play a role in the pathogenesis of facial nerve paralysis.