Peripheral facial weakness

NOTE: This pathway is intended for use in patients presenting with a peripheral pattern of facial weakness and questions are designed to help differentiate between the different etiologies. Peripheral (lower motor neuron) facial weakness is characterized by weakness involving both the upper and lower portion of the face. This presentation localizes most commonly to the facial nerve and its branches and less commonly within the facial nucleus (within the lower portion of the dorsolateral pons), or within the subarachnoid space (within the cerebellopontine cistern). The most common cause of lower motor neuron pattern of facial weakness is Bell’s Palsy, which typically involves one side of the face and is associated with reactivation of latent herpes viruses. Many other etiologies for facial weakness exist and can be differentiated based on associated symptoms, medical history, pattern of weakness (ipsilateral versus bilateral) and other associated exam findings.