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Bell's Palsy
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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
Gene
ral
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
Corticosteroid
s 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
Corticosteroid
s:
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
Corticosteroid
s
More recent studies show primary improvement with
Corticosteroid
s
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
Corticosteroid
s (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 Zoster
Virus
)
Severe pain
Aural pain
Anterior facial pain
Radicular pain
Complications
Corneal Ulcer
ation
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]
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