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Bell's Palsy

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Bell's Palsy, Bells Palsy, Facial Nerve Paralysis, Facial Nerve Palsy

  • Definition
  1. Idiopathic, acute Facial Nerve Paralysis
  • Background
  • History
  1. Named for Sir Charles Bell (1774-1842) who first described the syndrome
  • Epidemiology
  1. Incidence: 15-30 per 100,000 per year (45,000 per year in U.S.)
  2. No gender predominance
  3. Incidence peaks at age 40-49 years
  • Pathophysiology
  1. Facial Nerve inflammation at Geniculate Ganglion (risk of ischemia, demyelination)
  2. Associated with Herpesvirus infection in 30% of cases
  • Risk Factors
  1. Diabetes Mellitus (comorbid in 10% of cases)
  2. Pregnancy (associated with 3 fold increased risk)
  3. Herpesvirus infection (comorbid in 30% of cases)
    1. Herpes Simplex Virus
    2. Varicella Zoster Virus
    3. Epstein-Barr Virus
  • History
  • Red Flags suggestive of other Facial Nerve Paralysis Cause
  1. Gradual onset over >2 weeks
    1. Suggests mass lesion
  2. Forehead not involved
    1. Suggests central nervous system cause (supranuclear lesion)
    2. Facial Nerve motor nucleus is divided
      1. Dorsal aspect (forehead innervation) and ventral aspect (lower facial innervation)
      2. Both sides of the brain provide input to the dorsal aspect (forehead)
        1. Hence lack of forehead involvement implies an Upper Motor Neuron Lesion
      3. Only one side of the brain provides input to the ventral aspect (lower face)
  3. Bilateral involvement
    1. Suggests autoimmune Polyneuropathy
  4. Recent new medications (e.g. Influenza Vaccine)
  5. Recent Tick Bite
    1. Consider Lyme Disease
  6. Fever
    1. Consider infectious cause such as Otitis Media
  7. Rash
    1. Vesicular rash (Herpes Zoster)
    2. Erythema Migrans (Lyme Disease)
  • Exam
  1. Head and neck
    1. Ear canal
    2. Tympanic Membrane
    3. Mouth and pharynx
    4. Parotid Gland
  2. Neurologic Exam
    1. Cranial Nerve Exam
      1. Test Cranial Nerve 7 bilaterally on lower face and forehead
    2. Extremity Motor Exam and Sensory Exam
  3. Skin
  • Symptoms
  1. Idiopathic Facial Nerve Paralysis
    1. Hypoesthesia or dysesthesia (80%)
      1. Glossopharyngeal Nerve dysfunction
      2. Trigeminal Nerve dysfunction
    2. Facial or retroauricular pain (60%)
    3. Dysgeusia (57%)
    4. Hyperacusis (30%)
    5. Vagal nerve motor weakness (20%)
    6. Decreased Lacrimation (17%)
    7. Trigeminal Nerve motor weakness (3%)
    8. Dyskinesis (e.g. mouth twitching while blinking, or winking while smiling)
  2. References
    1. Adour (1982) N Engl J Med 307: 348-51 [PubMed]
  1. Preserved facial sensation
  2. Mouth and nasolabial changes
    1. Loss of facial creases and nasolabial fold
    2. Corner of mouth droops
  3. Eye changes
    1. No closure or decreased closure of upper Eyelid
    2. Lower Eyelid sag
    3. Decreased tear production
  4. No furrow over forehead (forehead appears flattened)
    1. Critical to recognize when the forehead and Eyelid are not involved
    2. Lack of forehead and Eyelid involvement suggests an Upper Motor Neuron Lesion such as a CVA
  1. Grade 1: Normal Facial Nerve Function
  2. Grade 2: Mild Facial Nerve Dysfunction
    1. Gross
      1. Slight weakness on close examination
      2. Synkinesis slight
    2. Rest: Normal symmetry and tone
    3. Motor Exam
      1. Forehead: Moderate to good function
      2. Eyes: Complete closure with minimum effort
      3. Mouth: Slight asymmetry
  3. Grade 3: Moderate Facial Nerve Dysfunction
    1. Gross:
      1. Obvious difference between sides (not disfiguring)
      2. Synkinesis noticeable
    2. Rest: Normal symmetry and tone
    3. Motor Exam
      1. Forehead: slight to Moderate movement
      2. Eyes: Complete closure with effort
      3. Mouth: Slightly weak with maximal effort
  4. Grade 4: Moderately Severe Facial Nerve Dysfunction
    1. Gross
      1. Obvious weakness
      2. Disfiguring asymmetry
    2. Rest: Normal symmetry and tone
    3. Motor Exam
      1. Forehead: No motor function
      2. Eyes: Incomplete closure
      3. Mouth: Asymmetric with maximal effort
  5. Grade 5: Severe Facial Nerve Dysfunction
    1. Gross: Barely perceptible motion
    2. Rest: Asymmetry
    3. Motor Exam
      1. Forehead: No motor function
      2. Eyes: Incomplete closure
      3. Mouth: Slight movement
  6. Grade 6: Total Facial Nerve Paralysis
  7. References
    1. House (1985) Otolaryngol Head Neck Surg 93:146-7 [PubMed]
  • Differential Diagnosis
  • Labs
  1. Labs are not indicated in isolated peripheral Facial Nerve Paralysis
  2. Serum Glucose is not routinely recommended
    1. Diabetes Mellitus does not cause Bell's Palsy, is simply a predisposing factor
  3. Lyme Antibody titer is not routinely recommended
    1. Lyme peripheral facial palsy is almost always associated with other findings (e.g. Arthritis, facial swelling, rash)
    2. Isolated Facial Nerve Palsy is not typically due to Lyme Disease
    3. However, consider lymes test in bilateral Facial Nerve involvement
    4. Kuiper (1992) Arch Neurol 49(9): 940-3 [PubMed]
  1. Benefits
    1. MRI Identifies central causes (Schwannoma, Hemangioma, meningioma and Cholesteatoma)
    2. MRI offers prognostic information based on nerve contrast enhancement
  2. Indications
    1. Suspected central cause (see Red Flags above)
    2. Persistent or progressive peripheral Facial Nerve Palsy lasting >2 months
    3. Facial twitching or spasm
  1. Rewetting the eye
    1. Frequent use of preservative-free artificial tears (every 15 to 30 minutes)
    2. Refresh PM ointment six times daily
  2. Protective glasses with side pieces
    1. Use in outdoors, drafty, dusty areas
    2. Alternatively can use eye shield or cup
  3. Avoid grinding, sanding, or sawing
  4. At night:
    1. Apply bland ointment (Refresh PM, Lacri-Lube)
    2. Tape eye shut
  5. Ophthalmology Consultation indicated for incomplete Eyelid closure persisting for weeks
    1. Risk of permanent ocular injury from drying
  1. Approach
    1. Start Corticosteroid within 72 hours of onset
    2. Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
    3. Consider Lyme Disease management if suggested by history or exam
      1. Doxycycline (preferred) 100 mg bid or Amoxicillin 500 mg tid for 14-21 days
  2. High dose Corticosteroids: Prednisone (primary intervention)
    1. Adult: 60-80 mg orally daily for 7 days
    2. Child: 2 mg/kg/day (up to adult dosing) for 7 days
    3. Salinas (2010) Cochrane Database Syst Rev (3):CD001942 +PMID:20238317 [PubMed]
  3. Antiviral agents (optional)
    1. Mechanism
      1. Based on reactivated HSV hypothesis
    2. Indications
      1. Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
    3. Efficacy
      1. Original studies showed synergistic benefit with antivirals in combination with Corticosteroids
      2. More recent studies show primary improvement with Corticosteroids and only marginal added benefit with antivirals
      3. Reasonable to offer antivirals in moderate to severe cases, but patients should be counseled on low efficacy
    4. Agents
      1. Acyclovir
        1. Adult: 400 mg five times per day for 7 days
        2. Child (>2 years): 80 mg/kg daily (max: 3200 mg/day) divided every 6 hours for 5 days
      2. Valacyclovir
        1. Age >12 years: 1 gram orally three times daily for 7 days
    5. References
      1. Gronseth (2012) Neurology 79(22): 2209-13 [PubMed]
      2. Adour (1996) Ann Otol Rhinol Laryngol 105:371-8 [PubMed]
      3. Hato (2007) Otol Neurotol 28: 408-13 [PubMed]
      4. Hato (2003) Otol Neurotol 24: 948-51 [PubMed]
  • Management
  • Associated Conditions
  1. Otitis Media or Mastoiditis Complications
    1. IV antibiotics
    2. Otolaryngology Consultation for possible wide incision of Tympanic Membrane
  2. Herpes Zoster Oticus (Ramsay Hunt Syndrome)
    1. See Herpes Zoster for antiviral agents
    2. May be associated with Tinnitus and Hearing Loss
    3. High dose Corticosteroids (1 mg/kg/day)
      1. Avoid in Diabetes Mellitus, peptic ulcer, Glaucoma
  • Management
  • Referral Indications
  1. Otitis Media complications
  2. Mastoiditis complications
  3. Signs of secondary cause
    1. Intracranial lesion or nerve impingement
  4. Incomplete Eyelid closure persisting for weeks
    1. Risk of permanent ocular injury from drying
    2. Referral to ophthalmology for management beyond artificial tears
  5. Other procedure referrals not routinely recommended
    1. Facial Nerve decompression surgery (may rarely be indicated)
    2. Physical Therapy (no evidence of benefit in Bell's Palsy)
  • Prognosis
  • Factors associated with poor prognosis
  1. Worse Prognosis with time needed for recovery
    1. No recovery by 3 weeks suggests worse prognosis (15% of cases)
    2. Further recovery occurs over 3-5 months
  2. Hyperacusis
  3. Diabetes Mellitus
  4. Hypertension
  5. Pregnancy
  6. Facial Nerve with severe degeneration by EMG
  7. Decreased tearing
  8. Age over 60 years
  9. Ramsay Hunt Syndrome (Herpes ZosterVirus)
  10. Severe pain
    1. Aural pain
    2. Anterior facial pain
    3. Radicular pain
  • Complications
  1. Corneal Ulceration
  2. Permanent Eyelid weakness
  3. Permanent facial asymmetry
  • Prognosis
  1. Early recovery (85%) within 3 weeks
  2. Prolonged recovery (15%) over 3-5 months
    1. Slight residual deficit: 12%
    2. Mild residual deficit: 13%
    3. Severe residual deficit: 4%
      1. Facial weakness
      2. Contracture or spasm
  3. Recurrence: 8% of cases
    1. Higher risk of recurrence in Diabetes Mellitus
  • Course
  1. Maximal weakness at 3-7 days after onset
  2. Most cases (85%) improve within 3 weeks even without treatment
    1. Additional improvement may require up to 5 months
    2. Prolonged recovery duration required for nerve regeneration