Facial nerve palsy

Abstract

Facial neuropathy is the most common cranial neuropathy, due to its extensive course and multiple sites of potential injury. The causes of facial neuropathy are many, but 70% are diagnosed as Bell’s palsy, an idiopathic syndrome but increasingly being associated with herpes simplex virus infection as the cause of the majority of cases. Ramsay Hunt syndrome (herpes zoster oticus) is the second most common cause. Facial neuropathy causes weakness of the muscles of facial expression on the ipsilateral side, and can be distinguished from a central, or upper motor neuron, caused by the involvement of forehead muscles. Taste, hearing, salivation, lacrimation, and sensation over the ipsilateral ear and the face may also be disturbed. Diagnosis can be confirmed by electrodiagnostic testing or MRI but is often not necessary. Treatment is directed at the underlying cause. In cases of Bell’s palsy a short course of steroids has been shown effective, if started within 72 h of onset. Treatment with antiviral agents against herpes virus is probably best reserved for patients with severe or complete facial neuropathy or those with Ramsay Hunt syndrome.