Facial paralysis

Background

Bilateral course of facial nerve. Note that the forehead muscles receive innervation from both hemispheres of the brain, which is why there is forehead sparing for stroke but not Bell's palsy (or other peripheral facial nerve injury).

• Key to distinguish between central and peripheral facial nerve palsy

Causes

• Central
  • CVA
• Peripheral
  • Idiopathic (Bell's palsy)
  • Lyme disease
  • Varicella-zoster
  • HSV
  • Facial trauma

Clinical Features

A person attempting to show his teeth and raise his eyebrows with Bell's palsy on his right side; notice how the forehead is NOT spared).

Patient with stroke (forehead sparing).

Central Process

• Forehead "sparing" or normal muscle tone of the forehead

Peripheral Process

• Weakness of forehead muscles

Central and Peripheral

• Unable to close eye
• Loss of nasolabial fold
• Asymmetric smile

Differential Diagnosis

Facial paralysis

• Bell's palsy
• CVA
• Trigeminal neuralgia
• Tick paralysis
  • Lyme disease
• Herpes zoster oticus (Ramsay Hunt syndrome)
• CNS tumor
  • Acoustic neuroma or other cerebellopontine angle lesions
  • Meningioma
  • Cerebellar pontine angle
  • Facial nerve schwannoma
  • Parotid
  • Sarcoma
• Anesthesia nerve blocks
• Cerebral Aneurysms (vertebral, basilar, or carotid)

Evaluation

Central Process

• CT

Peripheral Process

• No labs or imaging routinely necessary
• Consider lyme serologies if endemic area

Management

Central Process

• Treat underlying pathology

Peripheral Process

• Prednisone (unless diagnosed Lyme disease)
• Empiric doxycycline if high suspicion for Lyme disease
• Consider valacyclovir for severe presentation if Lyme is negative
• Artificial tears
• Consider neurology follow-up

See Also

• Facial swelling