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Bell's Palsy
Aka: Bell's Palsy, Bells Palsy, Bell Palsy, Facial Nerve Paralysis, Facial Nerve Palsy, CN 7 Palsy
- See Also
- Facial Nerve Injury from Birth Trauma
- Facial Nerve Paralysis Causes
- Definitions
- Bell's Palsy (Facial Nerve Palsy)
- Idiopathic, acute Facial Nerve Paralysis
- Background: History
- Named for Sir Charles Bell (1774-1842) who first described the syndrome
- Epidemiology
- Incidence: 15-30 per 100,000 per year (45,000 per year in U.S.)
- No gender predominance
- Incidence peaks at age 40-49 years
- Pathophysiology
- Facial Nerve inflammation typically at Geniculate Ganglion (risk of ischemia, demyelination)
- Associated with Herpesvirus infection in 30% of cases
- Risk Factors
- Diabetes Mellitus (comorbid in 10% of cases)
- Pregnancy (associated with 3 fold increased risk)
- Herpesvirus infection (comorbid in 30% of cases)
- Herpes Simplex Virus
- Varicella Zoster Virus
- Epstein-Barr Virus
- History: Red Flags suggestive of other Facial Nerve Paralysis Cause
- Gradual onset over >2 weeks
- Suggests mass lesion
- Forehead not involved
- Suggests Central Nervous System cause (supranuclear lesion)
- Facial Nerve motor nucleus is divided
- Dorsal aspect (forehead innervation) and ventral aspect (lower facial innervation)
- Both sides of the brain provide input to the dorsal aspect (forehead)
- Hence lack of forehead involvement implies an Upper Motor Neuron Lesion
- Only one side of the brain provides input to the ventral aspect (lower face)
- Bilateral involvement
- Suggests autoimmune Polyneuropathy
- Lyme Disease
- Recent new medications (e.g. Influenza Vaccine)
- Lyme Disease Risk Factors (Tick Bite, endemic Lyme Disease region during peak season)
- Lyme Disease
- Fever
- Consider infectious cause such as Otitis Media
- Rash
- Vesicular rash (Herpes Zoster, Ramsay Hunt Syndrome)
- Erythema Migrans (Lyme Disease)
- Hearing Loss and Vestibular Symptoms or Ataxia
- Acoustic Neuroma
- Exam
- Head and neck
- External Ear and ear canal (e.g. Otitis Externa, Herpes Zoster, Ramsay Hunt Syndrome)
- Tympanic Membrane (e.g. Otitis Media)
- Mouth and pharynx (e.g. Herpes Simplex Virus)
- Parotid Gland
- Neurologic Exam
- Perform complete Neurologic Exam including gait
- Cranial Nerve Exam
- Test Cranial Nerve 7 bilaterally on lower face and forehead
- Extremity Motor Exam and Sensory Exam
- Skin
- Vesicular rash (Herpes Zoster, Ramsay Hunt Syndrome)
- Erythema Migrans (Lyme Disease)
- Symptoms
- Idiopathic Facial Nerve Paralysis
- Hypoesthesia or dysesthesia (80%)
- Glossopharyngeal Nerve dysfunction
- Trigeminal Nerve dysfunction
- Facial or retroauricular pain (60%)
- Dysgeusia (57%)
- Hyperacusis (30%)
- Vagal nerve motor weakness (20%)
- Decreased Lacrimation (17%)
- Trigeminal Nerve motor weakness (3%)
- Synkinesis (e.g. mouth twitching while blinking, or winking while smiling)
- References
- Adour (1982) N Engl J Med 307: 348-51 [PubMed]
- Signs: General
- Preserved facial Sensation
- Mouth and nasolabial changes
- Loss of facial creases and nasolabial fold
- Corner of mouth droops
- Eye changes
- No closure or decreased closure of upper Eyelid
- Lower Eyelid sag
- Decreased tear production
- No furrow over forehead (forehead appears flattened)
- Critical to recognize when the forehead and Eyelid are not involved
- Lack of forehead and Eyelid involvement suggests an Upper Motor Neuron Lesion such as a CVA
- Signs: Facial Nerve Grading (House-Brackman)
- Grade 1: Normal Facial Nerve Function
- Grade 2: Mild Facial Nerve Dysfunction
- Gross
- Slight weakness on close examination
- Synkinesis slight
- Rest: Normal symmetry and tone
- Motor Exam
- Forehead: Moderate to good function
- Eyes: Complete closure with minimum effort
- Mouth: Slight asymmetry
- Grade 3: Moderate Facial Nerve Dysfunction
- Gross:
- Obvious difference between sides (not disfiguring)
- Synkinesis noticeable
- Rest: Normal symmetry and tone
- Motor Exam
- Forehead: slight to Moderate movement
- Eyes: Complete closure with effort
- Mouth: Slightly weak with maximal effort
- Grade 4: Moderately Severe Facial Nerve Dysfunction
- Gross
- Obvious weakness
- Disfiguring asymmetry
- Rest: Normal symmetry and tone
- Motor Exam
- Forehead: No motor function
- Eyes: Incomplete closure
- Mouth: Asymmetric with maximal effort
- Grade 5: Severe Facial Nerve Dysfunction
- Gross: Barely perceptible motion
- Rest: Asymmetry
- Motor Exam
- Forehead: No motor function
- Eyes: Incomplete closure
- Mouth: Slight movement
- Grade 6: Total Facial Nerve Paralysis
- References
- House (1985) Otolaryngol Head Neck Surg 93:146-7 [PubMed]
- Differential Diagnosis
- See Facial Nerve Paralysis Causes
- Labs
- Labs are not indicated in isolated peripheral Facial Nerve Paralysis
- Serum Glucose is not routinely recommended
- Diabetes Mellitus does not cause Bell's Palsy, and is simply a predisposing factor
- Lyme Antibody titer is not routinely recommended
- Lyme peripheral facial palsy is almost always associated with other findings (e.g. Arthritis, facial swelling, rash)
- Isolated Facial Nerve Palsy is not typically due to Lyme Disease
- However, consider lymes test with risk factors
- Bilateral Facial Nerve involvement (high risk, treat as Lyme Disease while testing)
- Known recent deer Tick Bite
- Erythema Migrans (diagnostic without Lyme Titer)
- Peak season in endemic Lyme Disease region
- References
- Kuiper (1992) Arch Neurol 49(9): 940-3 [PubMed]
- Imaging: MRI Head
- Benefits
- MRI Identifies central causes (Schwannoma, Hemangioma, meningioma and Cholesteatoma)
- MRI offers prognostic information based on nerve contrast enhancement
- Indications
- Suspected central cause (see Red Flags above)
- Persistent or progressive peripheral Facial Nerve Palsy lasting >2 months
- Facial twitching or spasm
- Management: Loss of Blink Reflex
- Rewetting the eye
- Frequent use of preservative-free artificial tears (every 15 to 30 minutes)
- Refresh PM ointment six times daily
- Protective glasses with side pieces
- Use in outdoors, drafty, dusty areas
- Alternatively can use eye shield or cup
- Avoid grinding, sanding, or sawing
- At night:
- Apply bland ointment (Refresh PM, Lacri-Lube)
- Tape eye shut
- Ophthalmology Consultation indicated for incomplete Eyelid closure persisting for weeks
- Risk of permanent ocular injury from drying
- Management: Corticosteroids and Antivirals
- Approach
- Start Corticosteroid within 72 hours of onset
- Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
- Consider Lyme Disease management if suggested by history or exam
- Doxycycline (preferred) 100 mg bid or Amoxicillin 500 mg tid for 14-21 days
- High dose Corticosteroids: Prednisone or Prednisolone (primary intervention)
- Adult: 60-80 mg orally daily for 7 days
- Child: 2 mg/kg/day (up to adult dosing) for 7 days
- Salinas (2010) Cochrane Database Syst Rev (3):CD001942 +PMID:20238317 [PubMed]
- Antiviral agents (optional)
- Mechanism
- Based on reactivated HSV hypothesis
- Indications
- Findings consistent with Herpes Zoster, herpes simplex or Ramsay Hunt Syndrome (e.g. vesicular rash)
- Antiviral may be considered in moderate to severe cases (House-Brackman Grade 4 and above)
- Efficacy of empiric antiviral use (excluding cases of herpetic, vesicular rashes which should be treated)
- Original studies showed synergistic benefit with antivirals in combination with Corticosteroids
- More recent studies show primary improvement with Corticosteroids
- Only marginal added benefit with antivirals
- Reasonable to offer antivirals in moderate to severe cases
- However patients should be counseled on low efficacy of antivirals
- Agents
- Acyclovir
- Adult: 400 mg five times per day for 7 days
- Child (>2 years): 80 mg/kg daily (max: 3200 mg/day) divided every 6 hours for 5 days
- Valacyclovir
- Age >12 years: 1 gram orally three times daily for 7 days
- References
- Gronseth (2012) Neurology 79(22): 2209-13 [PubMed]
- Adour (1996) Ann Otol Rhinol Laryngol 105:371-8 [PubMed]
- Hato (2007) Otol Neurotol 28: 408-13 [PubMed]
- Hato (2003) Otol Neurotol 24: 948-51 [PubMed]
- Management: Associated Conditions
- Otitis Media or Mastoiditis Complications
- IV antibiotics
- Otolaryngology Consultation for possible wide incision of Tympanic Membrane
- Herpes Zoster Oticus (Ramsay Hunt Syndrome)
- See Herpes Zoster for antiviral agents
- May be associated with Tinnitus and Hearing Loss
- High dose Corticosteroids (1 mg/kg/day)
- Avoid in Diabetes Mellitus, peptic ulcer, Glaucoma
- Management: Referral Indications
- Otitis Media complications
- Mastoiditis complications
- Signs of secondary cause
- Intracranial lesion or nerve impingement
- Incomplete Eyelid closure persisting for weeks
- Risk of permanent ocular injury from drying
- Referral to ophthalmology for management beyond artificial tears
- Other procedure referrals not routinely recommended
- Facial Nerve decompression surgery (may rarely be indicated)
- Physical Therapy (no evidence of benefit in Bell's Palsy)
- Prognosis: Factors associated with poor prognosis
- Worse Prognosis with time needed for recovery
- No recovery by 3 weeks suggests worse prognosis (15% of cases)
- Further recovery occurs over 3-5 months
- Hyperacusis
- Diabetes Mellitus
- Hypertension
- Pregnancy
- Facial Nerve with severe degeneration by EMG
- Decreased tearing
- Age over 60 years
- Ramsay Hunt Syndrome (Herpes ZosterVirus)
- Severe pain
- Aural pain
- Anterior facial pain
- Radicular pain
- Complications
- Corneal Ulceration
- Permanent Eyelid weakness
- Permanent facial asymmetry
- Prognosis
- Early recovery (85%) within 3 weeks
- Prolonged recovery (15%) over 3-5 months
- Slight residual deficit: 12%
- Mild residual deficit: 13%
- Severe residual deficit: 4%
- Facial weakness
- Contracture or spasm
- Recurrence: 8% of cases
- Higher risk of recurrence in Diabetes Mellitus
- Course
- Maximal weakness at 3-7 days after onset
- Most cases (85%) improve within 3 weeks even without treatment
- Additional improvement may require up to 5 months
- Prolonged recovery duration required for nerve regeneration
- References
- Herbert et al in Herbert (2015) EM:Rap 15(11): 3-4
- Zalvan (1999) Consultant 39(1):39-48
- Zvonar and Welsh (2021) Crit Dec Emerg Med 35(2): 25
- Albers (2014) Am Fam Physician 89(3): 209-12 [PubMed]
- Gilden (2004) N Engl J Med 351:1323-31 [PubMed]
- Holland (2004) BMJ 329:553-7 [PubMed]
- Tiemstra (2007) Am Fam Physician 76:997-1002 [PubMed]