AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Background

Bell palsy is an acute, idiopathic, unilateral, peripheral, lower-motor-neuron facial-nerve paralysis that gradually resolves over time in 80-90% of cases. Its cause is unknown, though it appears to be a polyneuritis with possible viral, inflammatory, autoimmune, and ischemic etiologies. Increasing evidence implicates herpes simplex type I and herpes zoster virus reactivation from cranial-nerve ganglia.

Determining whether facial-nerve paralysis is peripheral or central is a key step in the diagnosis. A lesion involving the central motor neurons above the level of the facial nucleus in the pons causes weakness of the lower face alone. Thorough history taking and examination, including the ears, nose, throat, and cranial nerves, must be performed. If the clinical findings are doubtful or if paralysis lasts longer than 6-8 weeks, further investigations, including gadolinium-enhanced MRI of the temporal bones and pons, should be considered.

Bell palsy is more common in adults, in people with diabetes, and in pregnant women than in others. Bell palsy recurs in 3-10% of patients, either on the same side or on the opposite side of the face. Recurrent or bilateral disease should suggest myasthenia gravis.

Treatment overview

Treatment of Bell palsy should be conservative and guided by the severity and probable prognosis in each particular case. However, the relationship with the herpes simplex virus has become even more apparent, and antiviral treatment combined with corticosteroids has become accepted for treating patients with milder degrees of Bell palsy. Electrodiagnostic tests (eg, stapedius reflex test, evoked facial-nerve electromyography [EMG], audiography) may help improve the accuracy of prognosis in difficult cases.

Topical ocular therapy is useful in all cases, except for those in which the condition is severe or prolonged. In these cases, surgical management is best. Several procedures are aimed at protecting the cornea from exposure and achieving facial symmetry. These procedures help eliminate the need for constant use of lubrication drops or ointments, they improve cosmesis, and they preserve vision on the affected side.

Anatomy

The facial nerve travels a 30-mm interosseous course through the internal auditory canal (with the eighth cranial nerve) and through the internal fallopian canal in the petrous temporal bone. This bony confinement limits the amount that the nerve can swell and thereby cause acute paralysis.

The facial nerve arises from its nucleus in the pons and exits at the cerebellopontine angle, where the nervus intermedius (which is responsible for lacrimation, salivation, and taste) and the nerve to the stapedius muscle joint are. The facial nerve travels with the vestibulocochlear nerve through the internal auditory canal and the facial (fallopian) canal in the temporal bone. The parasympathetic fibers directed toward the pterygopalatine ganglion and lacrimal gland exit at the geniculate ganglion as the greater petrosal nerve.

While coursing through the temporal bone, a branch leaves to the stapedius and proceeds distally as the chorda tympani to supply the salivary glands.

The facial nerve exits the stylomastoid foramen and divides into 5 branches in the parotid gland to innervate the facial muscles.

Pathophysiology

By definition, Bell palsy is idiopathic. Possible etiologies include infections, particularly herpes simplex (but also herpes zoster, Lyme disease, syphilis, Epstein-Barr viral infection, HIV, and mycoplasma); inflammation alone; and microvascular disease (diabetes mellitus and hypertension).

Frequency

United States

The rate is 20-30 cases per 100,000 population.

International

The rate worldwide is approximately 10-30 cases per 100,000 population.

Mortality/Morbidity

• This condition is 4.5 times more common in people with diabetes, 3.3 times more common in pregnant women, and more common in people with immunocompromise or preeclampsia than in others.
• Indicators of a poor prognosis are age older than 60 years, no recovery by 3 weeks, complete facial palsy, severe pain, and severe degeneration of the facial nerve (as assessed by means of evoked EMG testing).

Sex

The incidences are roughly equal in men and women.

Age

Bell palsy is rare in children. Peak ages are 20-40 years. The disease also occurs in elderly persons aged 70-80 years.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

History

See Physical.

Physical

• Early symptoms
• • Weakness of the facial muscles
  • Poor eyelid closure
  • Aching of the ear or mastoid (60%)
  • Alteration of taste (57%)
  • Hyperacusis (30%)
  • Tingling or numbness of the cheek/mouth
  • Epiphora
  • Ocular pain
  • Blurred vision
• Early ocular complications
• • Lagophthalmos
  • Paralytic ectropion of the lower lid
  • Corneal exposure
  • Brow droop
  • Upper eyelid retraction
  • Decreased tear output/poor tear distribution
  • Loss of nasolabial fold
  • Corneal erosion, infection, and ulceration (rare but may occur)
• Late ocular manifestations
• • Mild, generalized mass contracture of the facial muscles, rendering the affected palpebral fissure narrower than the opposite one (after several months)
  • Aberrant regeneration of the facial nerve with motor synkinesis
  • • Reversed jaw winking (ie, contracture of the facial muscles with twitching of the corner of the mouth or dimpling of the chin occurring simultaneously with each blink)
    • Autonomic synkinesis (ie, crocodile tears-tearing with chewing)
  • Rare, permanent, disfiguring facial paralysis
• Classification for facial nerve deficits

1. Normal 
2. Mild dysfunction (normal symmetry at rest, ability to close lids with minimal effort and slight asymmetry, ability to move mouth with maximal effort)
3. Moderate dysfunction (mild asymmetry, no functional impairment, ability to close lids and move mouth with maximal effort) 
4. Moderately severe dysfunction (obvious asymmetry, no movement of brows, unable to close lids completely, inability to move corner of mouth) 
5. Severe dysfunction (only barely perceptible motion, obvious asymmetry with droop of mouth and absent nasolabial fold, slight movement of eyelids)
6. Total paralysis

Causes

By definition, Bell palsy is idiopathic. Possible etiologies include infections (herpetic, Lyme disease, Epstein-Barr viral infection, HIV, and mycoplasma), inflammation, and microvascular disease (diabetes mellitus and hypertension).

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Other Problems to be Considered

Facial nerve schwannoma
Leukemia/lymphoma
Mycoplasma
Nasopharyngeal carcinoma
Parotid gland tumor
Geniculate ganglion infection
Pontine lesions
Cerebellopontine angle disorders
Otitis media
Parotid gland disease
Congenital malformation
Melkersson-Rosenthal syndrome
Guillain-Barré syndrome
Trauma

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Lab Studies

• No specific diagnostic tests are available for Bell palsy.
• In consideration of the differential diagnosis, the following tests may be beneficial:
• • Determination of the Lyme titer
  • Rapid plasma reagin (RPR) and/or venereal disease research laboratory (VDRL) test or fluorescent treponemal antibody absorption (FTA-ABS) test
  • HIV screening by means of enzyme-linked immunosorbent assay (ELISA) and/or Western blot
  • CBC determination
  • Determination of the erythrocyte sedimentation rate

Imaging Studies

• Perform gadolinium-enhanced MRI when findings are atypical or when the facial-nerve paralysis appears central to rule out a tumor or vascular compression.

Other Tests

• Perform careful clinical examination to evaluate for possible causes of facial paralysis.
• • Bell palsy rarely occurs with other cranial-nerve palsies or brainstem signs.
  • In children, facial palsy may be caused by pontine glioma, whereas in young and middle-aged adults, facial palsy can be an early sign of a cerebellopontine tumor.
• Time must also be taken to examine the patient's skin for signs of squamous cell carcinoma, which can invade the facial nerve, and parotid gland disease.

Procedures

• Possible facial-nerve EMG
• Lumbar puncture with analysis

TREATMENT

Section 6 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Medical Care

• Systemic therapy
• • The use of corticosteroids for Bell palsy is still controversial. However, a short course of high-dose corticosteroids in the first week of onset may be effective in improving the patient's prognosis. Despite this possibility, the use of corticosteroids alone did not have a significant benefit in randomized controlled trials.
  • Although the use of oral antiviral agents (eg, acyclovir, valacyclovir) is also controversial, these drugs are used in the early treatment of Bell palsy. Despite conflicting findings overall, a couple randomized controlled trials have shown benefit with combined corticosteroids and antiviral therapy, with outcomes such as improved return of muscle motion and shortened recovery times. Many physicians treat Bell palsy in the first week of onset (ideally within the first 72 h) with a 1-week course of combined steroid and antiviral treatment.
• Local therapy
• • In most cases, topical ocular lubrication (with artificial tears during the day and lubricating ophthalmic ointment at night, or occasionally ointment day and night) is sufficient to prevent the complications of corneal exposure.
  • Occluding the eyelids by using tape or by applying a patch for 1 or 2 days may help to heal corneal erosions. Care must be taken to prevent worsening the abrasion with the tape or a patch by ensuring that the eyelid is securely closed.
  • External eyelid weights are available to improve mechanical blink. The weights are attached to the upper lid with an adhesive and are available in different skin tones.
  • Clear plastic wrap, cut to 8 X 10 cm and applied with generous amounts of ointment as a nighttime occlusive bandage, may be required.
  • Lower-lid ectropion or droop can temporarily be helped by applying tape below the lid margin in the center of the lower lid; pull the lid laterally and upward to anchor on the orbital rim.
  • Punctal plugs may be helpful if dryness of the cornea is a persistent problem.
  • Botulinum toxin can be injected transcutaneously or subconjunctivally at the upper border of the tarsus and aimed at the levator muscle to produce complete ptosis and to protect the cornea.
  • Botulinum toxin may help in relaxing the facial muscles after they have developed mass contraction, though the results are not as satisfying as in patients with Bell palsy as in patients with idiopathic hemifacial spasm.

Surgical Care

Surgery to decompress the facial nerve is controversial when performed in patients with complete Bell palsy that has not responded to medical therapy and with greater than 90% axonal degeneration, as shown on facial-nerve EMG within 3 weeks of the onset of paralysis. The problem must be localized with MRI; then, the surgeon can decide if the maxillary segment should be decompressed externally or if the labyrinthine segment and geniculate ganglion should be decompressed by way of a middle-fossa craniotomy.

• Procedures to correct lower lid droop and ectropion  
• • The suborbicularis oculi fat (SOOF) lift is designed to lift and suspend the midfacial musculature. The SOOF is deep to the orbicularis oculi muscle and superficial to the periosteum below the inferior orbital rim. Lifting the SOOF may also elevate the upper lip and the angle of the mouth to improve facial symmetry. A SOOF lift is commonly done in conjunction with a lateral tarsal strip procedure to tighten the eyelid.
  • A lateral tarsal strip procedure is performed to correct horizontal lower-lid laxity and to improve apposition of the lid to the globe. First, lateral canthotomy and cantholysis is performed. Then, the anterior lamella is removed, and the lateral tarsal strip is shortened and attached to the periosteum at the lateral orbital rim.
• Procedures to correct lagophthalmos
• • Implantable devices have been used to restore dynamic lid closure in cases of severe, symptomatic lagophthalmos. These procedures are best for patients with poor Bell phenomenon and decreased corneal sensation. Gold or platinum weights, a weight-adjustable magnet, or palpebral springs can be inserted into the eyelids. Pretarsal gold-weight implantation is most commonly performed. The weight allows the upper eyelid to close with gravity when the levator palpebrae is relaxed. Therefore, patients must sleep with their head slightly elevated. The implants are inert and composed of 99.99% pure gold or platinum. Sizes range from 0.6-1.8 g. They are easily removed if nerve function returns. Complications include migration of the implant, inflammation, allergic reaction, or extrusion.
  • Tarsorrhaphy decreases horizontal lid opening by fusing the eyelid margins together to improve support of the precorneal lake of tears and to improve coverage of the eye during sleep. The procedure can be done in the office and is particularly suitable for patients who are unable or unwilling to undergo other surgery. Tarsorrhaphy can be performed laterally, centrally, or medially. The lateral procedure is most common; however, it can restrict the monocular temporal visual field. Central tarsorrhaphy offers good corneal protection, but it occludes vision and can be cosmetically unacceptable. Medial or paracentral tarsorrhaphy is performed lateral to the lacrimal puncta and can offer good lid closure without substantially affecting the visual field. The procedures can be completed as temporary or permanent measures. Permanent tarsorrhaphy is done if nerve recovery is not expected.
  • Transposition of the temporalis muscle can be used to reanimate the face and to provide lid closure by using the fifth cranial nerve. Strips from the muscle and fascia are placed in the upper and lower lids as an encircling sling. Patients initiate movement by chewing or clenching their teeth.
  • Reinnervation of the facial nerve by means of facial nerve grafting or hypoglossal-facial nerve anastomosis can be used in cases of clinically significant permanent paralysis to help restore relatively normal function to the orbicularis oculi muscle or eyelids.
• Brow ptosis is repaired with a direct brow lift. Care should be taken in the presence of corneal decompensation because lifting the brow can cause worsening of lagophthalmos, especially if lid closure is poor. A gold-weight implant can be placed or lower-lid resuspension can be performed simultaneously to prevent this complication.
• In the author's experience, surgical repair by using a combination of procedures tailored to the patients' clinical findings works well for improving symptoms and exposure. Most patients who have had severe corneal exposure due to lagophthalmos with or without paralytic ectropion received a combination of lateral tarsal strip placement, SOOF lift, and gold-weight implantation. Patients without severe exposure have received a single procedure or combinations of procedures.

Consultations

Depending on the workup results and clinical course, consultations with the following specialists may be indicated:

• Neurologist: An evaluation with a neurologist may be indicated for patients with a prolonged course, abnormal imaging studies, or inconsistencies in the findings on neurologic examination.
• Infectious disease specialist: An evaluation by a specialist in infectious disease may be indicated if results of laboratory studies are positive for Lyme disease, syphilis, or HIV infection.
• Ear, nose, and throat specialist: An evaluation with an otolaryngologist may be indicated for patients with a prolonged course for the consideration of surgical decompression of the facial nerve.

MEDICATION

Section 7 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

The goal of pharmacotherapy is to reduce morbidity by shortening the recovery time and preventing long-term complications.

Drug Category: Corticosteroids

The use of corticosteroids is controversial, but they may be beneficial in decreasing swelling and inflammation of the facial nerve. They have anti-inflammatory properties and cause profound and varied metabolic effects. In addition, these agents modify the body's immune response to diverse stimuli.

Drug Category: Antiviral agents

Use of these agents is controversial, but many cases of Bell palsy may be correlated with herpes simplex infection; therefore, an antiviral may be beneficial.

FOLLOW-UP

Section 8 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Further Outpatient Care

• Close follow-up care is needed to monitor the patient's ocular health.

In/Out Patient Meds

• See Medication.

Prognosis

• The prognosis for complete recovery in mild cases is almost universally good and occurs within days to weeks.
• In cases of severe paralysis, recovery may be prolonged for several months, especially in elderly patients. In 15-25% of patients with severe involvement, permanent facial weakness and aberrant regeneration of the facial nerve may result.

Patient Education

• The most important information to tell a patient is that the eye on the affected side of the face must be protected from excessive exposure.
• Depending on the severity of ocular exposure, necessary therapies range from frequent lubrication to surgical intervention.
• For excellent patient education resources, visit eMedicine's Brain and Nervous System Center. Also, see eMedicine's patient education article Bell Palsy.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

Medical/Legal Pitfalls

• Corneal exposure and possible corneal ulcer can occur if the patient is not instructed to keep the eye lubricated.

ACKNOWLEDGMENTS

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

The authors and editors of eMedicine gratefully acknowledge the contributions of previous coauthors, Zinaria Y Williams, MD, and Maxwell A Snead III, MD, to the development and writing of this article.

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Acknowledgments
• References

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• Bauer CA, Coker NJ. Update on facial nerve disorders. Otolaryngol Clin North Am. Jun 1996;29(3):445-54. [Medline].
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• Davies R. Facial nerve palsy. In: Levine M, ed. Manual of Oculoplastic Surgery. 2003. Butterworth-Heinemann: Boston, MA; 197-202.
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• Julian GG, Hoffmann JF, Shelton C. Surgical rehabilitation of facial nerve paralysis. Otolaryngol Clin North Am. Oct 1997;30(5):701-26. [Medline].
• Lee V, Currie Z, Collin JR. Ophthalmic management of facial nerve palsy. Eye. Dec 2004;18(12):1225-34. [Medline].
• Murphy TP. MRI of the facial nerve during paralysis. Otolaryngol Head Neck Surg. Jan 1991;104(1):47-51. [Medline].
• Olver JM. Raising the suborbicularis oculi fat (SOOF): its role in chronic facial palsy. Br J Ophthalmol. Dec 2000;84(12):1401-6. [Medline].
• Seiff SR, Chang J. Management of ophthalmic complications of facial nerve palsy. Otolaryngol Clin North Am. Jun 1992;25(3):669-90. [Medline].
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Article Last Updated: Feb 22, 2008