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Bell Palsy
Irina Pechenko, MD
Jeffrey B. Lanier, MD, FAAFP
image BASICS
DESCRIPTION
A peripheral lower motor neuron facial palsy, usually unilateral, which arises secondary to inflammation and subsequent swelling and compression of cranial nerve VII (facial) and the associated vasa nervorum
EPIDEMIOLOGY
  • Affects 0.02% of the population annually
  • Predominant sex: male = female
  • Median age of onset is 40 years but affects all ages.
  • Accounts for 60-75% of all cases of unilateral facial paralysis
  • Occurs with equal frequency on the left and right sides of the face
  • Most patients recover, but as many as 30% are left with facial disfigurement and pain.
Incidence
  • 20 to 30 cases per 100,000 people in the United States per year
  • Lowest in children ≤10 years of age; highest in adults ≥70 years of age
  • Higher among pregnant women
Prevalence
Affects 40,000 Americans every year
ETIOLOGY AND PATHOPHYSIOLOGY
  • Results from damage to the facial cranial nerve (VII)
  • Inflammation of cranial nerve VII causes swelling and subsequent compression of both the nerve and the associated vasa nervorum.
  • May arise secondary to reactivation of latent herpesvirus (herpes simplex virus [HSV] type 1 and herpes zoster virus) in cranial nerve ganglia or due to ischemia from arteriosclerosis associated with diabetes mellitus
Genetics
May be associated with a genetic predisposition, but it remains unclear which factors are inherited
RISK FACTORS
  • Pregnancy, specially associated with severe preeclampsia (1)[A]
  • Diabetes mellitus
  • Age >30 years
  • Exposure to cold temperatures
  • Upper respiratory infection (e.g., coryza, influenza)
  • Chronic HTN (1)[A]
  • Obesity (1)[A]
  • Migraine headache (2)[A]
COMMONLY ASSOCIATED CONDITIONS
  • HSV
  • Lyme disease
  • Diabetes mellitus
  • Hypertension
  • Herpes zoster virus
  • Ramsay-Hunt syndrome
  • Sjögren syndrome
  • Sarcoidosis
  • Eclampsia
  • Amyloidosis
image DIAGNOSIS
PHYSICAL EXAM
  • Neurologic
    • Determine if the weakness is caused by a problem in either the central or peripheral nervous systems.
    • Flaccid paralysis of muscles on the affected side, including the forehead
      • Impaired ability to raise the ipsilateral eyebrow
      • Impaired closure of the ipsilateral eye
      • Impaired ability to smile, grin, or purse the lips
      • Bell phenomenon: upward diversion of the eye with attempted closure of the lid
    • Patients may complain of numbness, but no deficit is present on sensory testing.
    • Examine for involvement of other cranial nerves.
  • Head, ears, eyes, nose, and throat
    • Carefully examine to exclude a space-occupying lesion.
    • Perform pneumatic otoscopic exam.
  • Skin: Examine for erythema migrans (Lyme disease) and vesicular rash (herpes zoster virus).
DIFFERENTIAL DIAGNOSIS
Etiologies include the following:
  • Infectious
    • Acute or chronic otitis media
    • Malignant otitis externa
    • Osteomyelitis of the skull base
  • Cerebrovascular
    • Brainstem stroke involving anteroinferior cerebellar artery
    • Aneurysm involving carotid, vertebral, or basilar arteries
  • Neoplastic (Onset of palsy is usually slow and progressive and accompanied by additional cranial nerve deficits and/or headache.)
    • Tumors of the parotid gland
    • Cholesteatoma
    • Skull base tumor
    • Carcinomatous meningitis
    • Leukemic meningitis
  • Traumatic
    • Temporal bone fracture
    • Mandibular bone fracture
  • Other
    • Multiple sclerosis
    • Myasthenia gravis (should be considered in cases of recurrent or bilateral facial palsy)
    • Guillain-Barré syndrome (may also present with bilateral facial palsy)
    • Sjögren syndrome
    • Sarcoidosis
    • Amyloidosis
    • Melkersson-Rosenthal syndrome
    • Mononeuritis or polyneuritis
DIAGNOSTIC TESTS & INTERPRETATION
Initial Tests (lab, imaging)
  • Blood glucose level (if diabetes a consideration)
  • Lyme titer, ELISA, and Western blot for immunoglobulin (Ig) M, IgG for Borrelia burgdorferi
  • ESR
  • Consider CBC.
  • Consider rapid plasma reagin test.
  • Consider HIV test.
  • In appropriate clinical circumstances, consider titers for varicella-zoster virus, cytomegalovirus, rubella, hepatitis A, hepatitis B, and hepatitis C.
Follow-Up Tests & Special Considerations
  • CSF analysis
    • CSF protein is elevated in 1/3 of cases.
    • CSF cells show mild elevation in 10% of cases with a mononuclear cell predominance.
    • Not routinely indicated
  • Salivary polymerase chain reaction for HSV1 or herpes zoster virus (largely reserved for research purposes)
  • Facial radiographs
    • In the setting of trauma, evaluate for fracture.
  • IV contrast-enhanced head CT
    • Evaluate for fracture.
    • Evaluate for stroke, if stroke is in the differential.
  • IV contrast-enhanced brain MRI
    • Evaluate for central pontine, temporal bone, and parotid neoplasms.
    • Not routinely indicated
Diagnostic Procedures/Other
  • Electromyograph: Nerve conduction on affected and nonaffected sides can be compared to determine the extent of nerve injury, especially if there is dense palsy or no recovery after several weeks.
  • Electroneurography: Evoked potentials of affected and nonaffected sides can be compared.
Test Interpretation
Invasive diagnostic procedures are not indicated because biopsy could further damage cranial nerve XII.
image TREATMENT
GENERAL MEASURES
  • Artificial tears should be used to lubricate the cornea.
  • The ipsilateral eye should be patched and taped shut at night to avoid drying and infection.
MEDICATION
  • Corticosteroids decrease inflammation and limit nerve damage, thereby reducing the number of patients with residual facial weakness.
  • P.121

  • Routine use of antiviral medication is not recommended. Antiviral agents targeting herpes simplex, when administered concurrently with corticosteroids, may further reduce the risk of unfavorable outcomes in patients with a dense Bell palsy (3)[A]:
    • Antivirals alone are less likely to produce full recovery than corticosteroids.
    • A combination of valacyclovir and steroids provides only minimal added benefit over steroid use alone (4)[B].
  • Corticosteroids
    • Prednisolone: total of 500 mg over 10 days, 25 mg PO BID
      • Treatment with prednisolone within 48 hours of palsy onset has shown higher complete recovery rates and less synkinesis compared with no prednisolone (5)[B].
      • Antivirals in combination with corticosteroids
        • Valacyclovir: 1,000 mg TID for 7 days plus prednisolone 60 mg/day for 5 days; then tapered by 10 mg/day for total treatment length of 10 days (4)[B].
      • Steroids are recommended for all cases of Bell palsy.
      • Controversial whether antiviral treatment is necessary with steroids
        • American Academy of Otolaryngology-Head and Neck Surgery recommends antiviral treatment in all cases of Bell palsy cases (6)[A].
      • There is a strong recommendation to use corticosteroids for all patients with Bell palsy and strong recommendation against of antiviral treatment alone (6)[A].
  • Contraindications
    • Documented hypersensitivity
    • Preexisting infections, including tuberculosis (TB) and systemic mycosis
  • Precautions: Use with discretion in pregnant patients and those with peptic ulcer disease and diabetes.
  • Significant possible interactions: measles-mumps-rubella, oral polio virus vaccine, and other live vaccines
Pregnancy Considerations
Steroids should be used cautiously during pregnancy; consult with an obstetrician.
ISSUES FOR REFERRAL
Patients may need to be referred to an ear, nose, and throat specialist or a neurologist.
ADDITIONAL THERAPIES
  • Physical therapy: strong evidence that physical therapy combined with drug treatment has positive effect on grade and time of recovery compared with drug treatment only (7,8,9)[A].
  • Electrostimulation and mirror biofeedback rehabilitation have limited evidence of effect (10)[C].
  • Acupuncture with strong stimulation has shown some therapeutic promise.
  • Routine use of eye-protective measures for patients with incomplete eye closure is recommended (6)[A].
SURGERY/OTHER PROCEDURES
  • Surgical treatment of Bell palsy remains controversial and is reserved for intractable cases.
  • There is an insufficient evidence to decide whether surgical intervention is beneficial or harmful in the management of Bell palsy (11)[B].
  • In those cases where surgical intervention is performed, cranial nerve XII is surgically decompressed at the entrance to the meatal foramen where the labyrinthine segment and geniculate ganglion reside.
  • Decompression surgery should not be performed >14 days after the onset of paralysis because severe degeneration of the facial nerve is likely irreversible after 2 to 3 weeks.
  • A routine surgical decompression is not recommended (6)[B].
image ONGOING CARE
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
  • Patients should start steroid treatment immediately and be followed for 12 months.
  • Patients who do not recover complete facial nerve function should be referred to an ophthalmologist for tarsorrhaphy.
PATIENT EDUCATION
American Academy of Family Physicians: http://www.aafp.org/afp/2007/1001/p1004.html
PROGNOSIS
  • Most patients achieve complete spontaneous recovery within 2 weeks. >80% recover within 3 months.
  • 85% of untreated patients will experience the first signs of recovery within 3 weeks of onset.
  • 16% are left with a partial palsy, motor synkinesis, and autonomic synkinesis.
  • 5% experience severe sequelae, and a small number of patients experience permanent facial weakness and dysfunction.
  • Poor prognostic factors include the following:
    • Age >60 years
    • Complete facial weakness
    • Hypertension
    • Ramsay-Hunt syndrome
  • The Sunnybrook and House-Brackmann facial grading systems are clinical prognostic models that identify Bell palsy patients at risk for nonrecovery at 12 months.
  • Treatment with prednisolone or no prednisolone and the Sunnybrook score are significant factors for predicting nonrecovery at 1 month (12)[C].
  • Patients with no improvement or progression of symptoms should be referred to ENT (6)[A] and may require neuroimaging to rule out neoplasms (6)[A].
REFERENCES
1. Katz A, Sergienko R, Dior U, et al. Bell's palsy during pregnancy: is it associated with adverse perinatal outcome? Laryngoscope. 2011;121(7): 1395-1398.
2. Peng KP, Chen YT, Fuh JL, et al. Increased risk of Bell palsy in patients with migraine: a nationwide cohort study. Neurology. 2015;84(2):116-124.
3. Thaera GM, Wellik KE, Barrs DM, et al. Are corticosteroid and antiviral treatments effective for bell palsy? A critically appraised topic. Neurologist. 2010;16(12):138-140.
4. Worster A, Keim SM, Sahsi R, et al. Do either corticosteroids or antiviral agents reduce the risk of long-term facial paresis in patients with new-onset Bell's palsy? J Emerg Med. 2010; 38(4):518-523.
5. Madhok V, Falk G, Fahey T, et al. Prescribe prednisolone alone for Bell's palsy diagnosed within 72 hours of symptom onset. BMJ. 2009;338:b255.
6. de Almeida JR, Guyatt GH, Sud S, et al. Management of Bell palsy: clinical practice guideline. CMAJ. 2014;186(12):917-922.
7. Teixeira LJ, Valbuza JS, Prado GF. Physical therapy for Bell's palsy (idiopathic facial paralysis). Cochrane Database Syst Rev. 2011;(12):CD006283.
8. Ferreira M, Marques EE, Duarte JA, et al. Physical therapy with drug treatment in Bell palsy: a focused review. Am J Phys Med Rehabil. 2015; 94(4):331-340.
9. Pourmomeny AA, Asadi S. Management of synkinesis and asymmetry in facial nerve palsy: a review article. Iran J Otorhinolaryngol. 2014; 26(77):251-256.
10. Alakram P, Puckree T. Effects of electrical stimulation on House-Brackmann scores in early Bell's palsy. Physiother Theory Pract. 2010;26(3): 160-166.
11. Axelsson S, Berg T, Jonsson L, et al. Prednisolone in Bell's palsy related to treatment start and age. Otol Neurotol. 2011;32(1):141-146.
12. Marsk E, Bylund N, Jonsson L, et al. Prediction of nonrecovery in Bell's palsy using Sunnybrook grading. Laryngoscope. 2012;122(4):901-906.
See Also
Amyloidosis; Diabetes Mellitus, Type 1; Diabetes Mellitus, Type 2; Herpes Simplex; Herpes Zoster (Shingles); Lyme Disease; Sarcoidosis; Sjögren Syndrome
Codes
ICD10
G51.0 Bell's palsy
Clinical Pearls
  • Initiate steroids immediately following the onset of symptoms.
  • Look closely at the voluntary movement on the upper part of the face on the affected side; in Bell palsy, all of the muscles are involved (weak or paralyzed); whereas in a stroke, the upper muscles are spared (because of bilateral innervation).
  • Protect the affected eye with lubrication and taping.
  • In areas with endemic Lyme disease, Bell palsy should be considered to be Lyme disease until proven otherwise.