Facial Nerve Palsy

Definition and Clinical Presentation

The American Academy of Otolaryngology-Head and Neck Surgery defines facial paralysis as the complete inability to move the face, while facial paresis indicates incomplete ability to move the face 1, 3
Bell's palsy, the most common form of facial nerve palsy, is defined as acute unilateral facial nerve paresis or paralysis with onset in less than 72 hours and without an identifiable cause 1, 4
Symptoms of facial nerve palsy typically develop rapidly and may include inability to close the eyelid, oral incompetence, dryness of the eye or mouth, taste disturbance, hyperacusis, and sagging of the eyelid or corner of the mouth 1, 2, 5

The exact mechanism of Bell's palsy is currently unknown, but a viral etiology is suspected, with facial paresis or paralysis thought to result from facial nerve inflammation and edema 2, 5

The American Academy of Otolaryngology-Head and Neck Surgery reports that Bell's palsy can affect men, women, and children, but is more common in those 15 to 45 years old, with higher incidence in patients with diabetes, upper respiratory ailments, compromised immune systems, and during pregnancy 1, 6

Other conditions that may cause facial paralysis include stroke, brain tumors, tumors of the parotid gland or infratemporal fossa, cancer involving the facial nerve, and systemic and infectious diseases such as Herpes zoster and Lyme disease 1

The American Academy of Otolaryngology-Head and Neck Surgery recommends that Bell's palsy be diagnosed by exclusion, with careful elimination of other causes, and that red flags such as advanced age, bilateral facial weakness, and new or worsening neurologic findings require further investigation 4, 6

The American Academy of Otolaryngology-Head and Neck Surgery recommends oral steroids within 72 hours of symptom onset, and that antiviral therapy alone is not recommended, but may be offered in combination with oral steroids 4, 7

The American Academy of Otolaryngology-Head and Neck Surgery reports that Bell's palsy is typically self-limited, with most patients beginning to show recovery within 2-3 weeks, and complete recovery typically occurring within 3-4 months 1, 7
Without treatment, facial function is completely restored in approximately 70% of patients with complete paralysis within 6 months, and up to 94% of patients with incomplete paralysis 7