Facial Paralysis: Etiology, Diagnosis, and Medical Treatment

Abstract

Knowledge of nerve anatomy as well as clinical signs of diseases affecting the facial nerve is essential in diagnosing and treating facial nerve disorders. This chapter reviews the more common causes of peripheral facial paralysis and discusses medical treatment strategies.

A central (upper motor neuron) lesion of the voluntary facial cortical representation due to thrombosis, hemorrhage, tumor, or trauma weakens the lower contralateral face. In a peripheral (lower motor neuron) facial lesion, both the lower and upper face are weakened ipsilateral to the injury.

Acute idiopathic peripheral facial palsy (Bell’s palsy) is the most common form of unilateral palsy (50–70%). Trauma, herpes zoster oticus, benign and malignant tumors, ear infection, Melkersson–Rosenthal syndrome, sarcoidosis (Heerfordt’s syndrome), Lyme disease, central nervous disease, and congenital (birth trauma or developmental) are other conditions affecting the facial nerve.

Bell’s palsy presents as rapid unilateral weakness of the face with no identifiable cause and some recovery within 3–6 months. Eye care to protect the cornea needs to be initiated. Recommended treatment is peroral prednisolone within 72 h and additional antivirals may be offered. About 70% of Bell’s palsy patients recover completely. Sequelae are facial muscle weakness, contracture, and synkinesis.

Simultaneous bilateral peripheral facial palsy is uncommon and requires a careful diagnostic evaluation. The most common causes are Guillain–Barré syndrome, Lyme disease, “bilateral Bell’s palsy,” Melkersson–Rosenthal syndrome, sarcoidosis (Heerfordt’s syndrome), Epstein–Barr and cytomegalovirus, HIV, meningitis, leukemia, and lymphoma. Trauma with skull base fracture and congenital Möbius syndrome are other causes.

In children, Bell’s palsy is the leading etiology of acquired acute peripheral facial palsy (about 40–50%) but is less frequent than in adults. Lyme disease as cause of palsy is more common in children. The most common cause of unilateral congenital palsy is birth-related trauma. The spontaneous recovery rate is approximately 90%, while developmental facial palsy in general will not improve. Bilateral palsy, cranial deficits/other malformations and/or family history of congenital facial palsy indicates a developmental origin as found in Möbius syndrome, Goldenhar syndrome, CHARGE syndrome, and congenital unilateral lower lip palsy.