SUMMARY:

Bell’s palsy is a temporary facial weakness or paralysis resulting from dysfunction of the VII^th cranial nerve. It almost always presents as rapid unilateral facial nerve paralysis which leads to partial or complete loss of voluntary facial muscle movement. It can also lead to oral incompetence and incomplete closure of the eyelid (lagopthalmos) which predisposes to eye injury. Bell’s palsy is the most common cause of unilateral facial paralysis affecting nearly 40,000 people in the US every year.  While the precise cause is unknown, onset is often related to viral infection (e.g., flu, adenoviruses, CMV, herpes simplex, herpes zoster)

KEY POINTS:

Clinical Presentation

• Unilateral facial nerve paralysis
  • There is loss of facial creases and nasolabial fold
  • Forehead unfurrows
  • Corner of the mouth droops
  • Eyelids cannot close and the lower lid sags
  • Bell’s phenomenon: When an attempt is made to close the eye, the eye rolls upward
• NOTE: If the patient can furrow their brow, suspect central lesion because of dual innervation to the  1^st branch of the facial nerve
• Rapid onset: Usually 72 hours from onset to maximum weakness
• Common age group: 15 to 45 years (both men and women)
• Pain: May be associated with ipsilateral pain surrounding the ear and face
• Differential (facial paralysis)
  • Systemic and infectious diseases: Lyme disease, sarcoidosis, zoster
  • CNS: Tumors, CVA
  • Non-CNS tumors: Parotid gland, infratemporal fossa, cancer involving the facial nerve

Risk Factors

• Pregnancy has been associated with Bell’s palsy
  • Also associated with severe preeclampsia
• Obesity
• Hypertension
• Diabetes
• Upper respiratory ailments

Testing

• There is no indication for routine laboratory testing
• Based on the clinical setting, Lyme disease can account for up to 25% of cases and serologies may be helpful
• Routine use of brain imaging is not recommended
  • However, if paralysis is inconsistent with Bell’s palsy, consider imaging to rule out CNS and other potential masses and lesions

Treatment

• Prednisone is recommended if started in 72 hours for patients ≥16 years
  • 50 to 60 mg daily for total of 10 days | Full dose for the first 5 days then taper over the next 5 days
  • Acyclovir or valacyclovir is optional to start and use together with steroids
• Eye protection
  • Can use eye patching or taping to prevent corneal abrasions, keratitis, and ulcerations

Follow-Up

• 85% of patients show partial recovery within three weeks of onset
• Complete recovery occurs in 70% of patients in 6 months
• Refer to specialist if
  • New or worsening neurologic symptoms appear at any time
  • Incomplete resolution at 3 months
  • Ocular complications

Learn More – Primary Sources:

American Academy of Otolaryngology Head and Neck Surgery Foundation Clinical practice guideline: Bell’s palsy

BMJ: Bell’s Palsy

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