Bell's palsy: a summary of current evidence and referral algorithm

Abstract

Spontaneous idiopathic facial nerve (Bell's) palsy leaves residual hemifacial weakness in 29% which is severe and disfiguring in over half of these cases. Acute medical management remains the best way to improve outcomes. Reconstructive surgery can improve long term disfigurement. However, acute and surgical options are time-dependent. As family practitioners see, on average, one case every 2 years, a summary of this condition based on common clinical questions may improve acute management and guide referral for those who need specialist input. We formulated a series of clinical questions likely to be of use to family practitioners on encountering this condition and sought evidence from the literature to answer them. The lifetime risk is 1 in 60, and is more common in pregnancy and diabetes mellitus. Patients often present with facial pain or paraesthesia, altered taste and intolerance to loud noise in addition to facial droop. It is probably caused by ischaemic compression of the facial nerve within the meatal segment of the facial canal probably as a result of viral inflammation. When given early, high dose corticosteroids can improve outcomes. Neither antiviral therapy nor other adjuvant therapies are supported by evidence. As the facial muscles remain viable re-innervation targets for up to 2 years, late referrals require more complex reconstructions. Early recognition, steroid therapy and early referral for facial reanimation (when the diagnosis is secure) are important features of good management when encountering these complex cases.

Keywords: Bell’s palsy; Herpes simplex; corticosteroids; cross facial nerve graft; facial nerve palsy; facial nerve paralysis; idiopathic; meatal segment..