Snapshot A 22-year-old man presents to his physician with facial drooping. He reports these symptoms began approximately 1 day prior to presentation. He denies any trauma to the face and past medical history is noncontributory. On physical examination, there is facial drooping of the right side of the face. The right nasolabial fold is absent and he is unable to close his right eye or raise the right side of his forehead. The rest of the neurologic exam is normal. Introduction Clinical definition a neurologic defict secondary to weakness of the facial nerve Epidemiology incidence 11-40 per 100,000 population demographic 15-45 years of age Etiology idiopathic herpes simplex virus varicella-zoster virus lyme disease sarcoidosis malignancy diabetes mellitus Pathogenesis facial nerve palsy may result from inflammatory or infectious insults to the facial nerve Prognosis most patients recover Anatomy The facial nerve is a mixed nerve that arises from the pontomedullary junction and contains motor fiber input to the facial muscles parasympathetic fibers to the lacrimal glands submandibular glands sublingual salivary glands afferent fibers from the taste receptors of the anterior two-thirds of the tongue external auditory canal and pinna Presentation Symptoms and physical exam unilateral facial weakness eye brow sagging inability to close the eye absence of the nasolabial fold corner of the mouth droops decreased tearing hyperacusis loss of taste sensation of the anterior two-thirds of the tongue Peripheral (lower motor neuron) vs central (upper motor neuron) lesion a lower motor neuron lesion involves the forehead a upper motor neuron lesion spares the forehead Studies Diagnostic criteria a clinical diagnosis Differential Stroke Multiple sclerosis Myasthenia gravis Guillain-Barre syndrome Treatment Medical glucocorticoids indication oral glucocorticoids is the mainstay of pharmacologic treatment in patients with acute idiopathic Bell's palsy Complications Ocular manifestations corneal drying and abrasion