A case of persistent hemifacial weakness.

: Hemifacial weakness, or palsy, results from disruption of communication between cortical motor centres and the facial musculature along the course of the facial nerve. Bell's palsy has a typical presentation of sudden onset, mild otalgia, altered facial sensation and/or taste, with no obvious prodrome. It represents over half of hemifacial weakness cases in primary care. However, as a diagnosis of exclusion, there are a number of key clinical features of more sinister diagnoses that must be considered. Acute hemifacial weakness secondary to isolated facial nerve palsy must be differentiated from acute cerebrovascular accident. The latter results in sparing of the brow musculature due to the bilateral innervation of the frontalis. Altered facial sensation and mild otalgia are common in Bell's palsy, however severe pain is suggestive of Ramsay Hunt syndrome. Recent facial or head trauma and surgery should also be excluded in causation. Patients with the following conditions should be referred: lagophthalmos if the weakness persists beyond a few days or ocular damage is suspected; Ramsay Hunt syndrome (immunocompromised patients, those with significant pain, and where intraoral vesicles prohibit oral intake); and palsy secondary to trauma or surgery. A parotid mass with facial palsy implies malignant change and must be referred within the two-week wait pathway. A history of progressive hearing loss and tinnitus with palsy also requires urgent referral to neuro-otology for assessment of cerebellopontine angle tumours. All cases of facial palsy associated with infective otological symptoms should be discussed with ENT.