Facial nerve paralysis

A loss or severe reduction of voluntary motor function in muscles innervated by the seventh cranial nerve (facial nerve), typically causing unilateral flaccid facial weakness with impaired facial expression, eye closure, and oral competence.

Causes

• Idiopathic facial nerve palsy (Bell's palsy)

• Viral and infectious causes

  • Herpes simplex virus (HSV)

  • Varicella-zoster virus (VZV)

  • Epstein-Barr virus (EBV)

  • Cytomegalovirus (CMV)

  • Lyme disease

  • Meningitis

• Neurological disorders

  • Stroke

  • Guillain-Barré syndrome

  • Multiple sclerosis

  • Sarcoidosis

• Trauma-related causes

  • Skull fracture

  • Temporal bone fracture

• Tumors and structural causes

  • Facial nerve neuroma

  • Vestibular schwannoma (acoustic neuroma)

  • Parotid gland tumors

• Iatrogenic facial nerve injury: Surgery involving the parotid gland or the temporal bone