Magnetic resonance imaging findings in bilateral Bell's palsy.

Bell's palsy (idiopathic facial paralysis) is the most common cause of unilateral peripheral facial neuropathy. Bilateral involvement occurs in less than 10% of cases. The authors describe a 20-year-old man with bilateral idiopathic facial weakness. Brain magnetic resonance imaging (MRI) showed abnormal bilateral enhancement of the proximal intracanalicular segments of VII/VIII nerve complexes. The enhancement was most prominent in the leptomeningeal regions. There was no facial nerve swelling. Three months later he had improving residual bifacial weakness. To the authors' knowledge, this is the first report of abnormal MRI findings in bilateral Bell's palsy.