Management of Bell's palsy.

Bell's palsy or idiopathic palsy is the most common disorder affecting the facial nerve. Diagnosis is primarily one of exclusion. There is typically an acute unilateral facial paresis that evolves in 24 to 48 hours. Etiology and pathophysiology are heavily disputed, and as of yet unknown. The natural history of Bell's palsy is favorable. Eight-four percent show satisfactory recovery without any treatment, however 16% suffer moderate to severe sequelae. Prognosis is influenced by degree of paresis, age of patient, and time until first signs of recovery. Prognostic testing currently involves various electrophysiological tests. More than 90% degeneration of the facial nerve carries a poor prognosis for recovery; these are the patients who may benefit from facial nerve decompression surgery. If surgery is performed it should be done early (< 21 days from onset of palsy) and should include a middle cranial fossa decompression. Steroids are generally agreed to be beneficial. Acyclovir would seem to be a promising drug; however studies have not adequately assessed its use.