• The facial nerve is the VII cranial nerve.
– Muscles of facial expression
– Sympathetic efferents to lacrimal and salivary glands
– Sensory afferents from tongue, external ear, and palate
– Taste afferents from anterior two-thirds of tongue
– Motor dysfunction causes ipsilateral facial paralysis
• Bell’s Palsy (Idiopathic): Most common cause of unilateral facial paralysis
– Acute to subacute (hours to days) onset of unilateral upper and lower facial weakness with variable symptoms of hyperacusis, dysgeusia, and dysfunctional lacrimation and salivation.
• Initial determinations:
– Peripheral versus central
– Accompanying clinical signs and symptoms indicating a non-idiopathic etiology
Non-isolated & central VII nerve palsy requires work-up
Bilateral facial nerve palsy and concomitant additional cranial neuropathies require special attention.
11–40/100,000 per year (1)[A]; more common ages 15–45 years
None recently reported
Bell’s Palsy: Pregnancy, diabetes, influenza, upper respiratory infection
• Bell’s Palsy: Sparse reports of familial cases
• Mobius syndrome: Congenital facial diplegia + variable abducens nerve palsy; sporadic
• Myotonic dystrophy: Autosomal dominant trinucleotide (CTG) repeat expansion on 19q13.3
Supranuclear, nuclear, infranuclear/peripheral dysfunction of the facial nerve
Bell’s Palsy: Idiopathic, possible viral-associated inflammation and/or demyelination
COMMONLY ASSOCIATED CONDITIONS
None known; see risk factors.
• Bell’s Palsy: Isolated, acute to subacute onset of unilateral upper and lower facial weakness with variably manifested hyperacusis, dysgeusia, and dysfunctional lacrimation and salivation
– Assess: Dysarthria, dysphagia, change of hearing and taste, ear and eye pain, diplopia, vertigo, ataxia, gait dysfunction, limb weakness, rashes, facial numbness, and pain
– Myasthenia Gravis (MG): Variable ptosis and diplopia, fatigable extremity weakness
– Demyelination/multiple sclerosis (MS): History of prior focal neurological deficits
– Guillain-Barré Syndrome (GBS): Preceding GI or upper respiratory infection
– Additional history: Trauma, neoplasia, ischemia, demyelinating disease
– Guides appropriate work-up for secondary causes
– Pain is atypical for Bell’s Palsy
– Consider Ramsay-Hunt Syndrome: HZV with vesicular eruption
– Systemic symptoms
• Determine if palsy is central or peripheral and if palsy exists in isolation
– At rest: Note asymmetry of muscle tone, blink pattern, widened palpebral fissure, flattened nasolabial fold, and lagophthalmus
• Motor activity: Smile and forced eyelid closure
– Note decreased function on affected side; Bell’s phenomenon
– Asses forehead/frontalis function
Ask patient to raise/furrow eyebrows and brow
Central palsies do not affect function of forehead/frontalis; peripheral palsies do
• Examine corneal sensation and reflex
• Examine other cranial nerves: V, VI, and VIII are of particular importance for anatomic localization.
• Examine for long tract signs, for example, extremity weakness.
DIAGNOSTIC TESTS & INTERPRETATION
Initial lab tests
Serum glucose, syphilis serology, CBC, Lyme titer, ACE, HgbA1c
Follow-up & special considerations
Consider: ESR, CRP, ANA, anti-acetylcholine receptor Abs, mono spot test, ANCA, HIV, CSF analysis, serology/stool culture for C. jejuni
• MRI is modality of choice to rule out secondary causes except in trauma cases (CT)
• Presentations requiring imaging
– Slow or insidious onset of palsy
– Central and bilateral nerve palsies
– Multiple cranial neuropathies
– Associated hearing loss and vertigo
– Attention: Ischemia (diffusion weighted images), masses, CP angle, pachymeningeal enhancement (sarcoid), meningoencephalitis (Lyme), skull base, and brainstem
Follow-up & special considerations
Disease specific for secondary causes
• EMG: GBS & MG; include repetitive stimulation, consider single fiber EMG
• CSF: Pleocytosis (infectious/inflammatory), albuminocytologic dissociation (GBS), Lyme, Ig index and oligoclonal bands (MS), ACE (sarcoid) and infectious work-up as appropriate
• Edrophonium test and Ice test (MG)
• Chest x-ray (sarcoid related adenopathy)
Mobius syndrome: Aplasia/hypoplasia of cranial nerve nuclei
• Infectious, inflammatory/demyelinating, infiltrative, neoplastic/metastatic, compressive, traumatic, and idiopathic
– Supranuclear: Ischemia, mass lesion
– Nuclear: Pontine glioma, ischemia, hemorrhage, demyelination, vascular lesions
– Cerebellopontine (CP) angle: Acoustic schwannoma, meningioma, choleastoma, glomus jugulare tumor (can involve cranial nerves VII – XII)
– Temporal bone/Skull base: Osteopetrosis, trauma, masses, Ramsay-Hunt syndrome, hemangioma, naso-pharyngeal carcinoma
– Subarachnoid space: Carcinomatous meningitis, GBS, TB, sarcoid, Lyme
– Other: MG, syphilis, parotid tumors, amyloid, sarcoma, diabetic mononeuropathy, HIV, lymphoma/leukemia, demyelination/MS, Paget’s disease, arteriovenous malformation
• Bilateral VII Nerve palsy: Lyme disease, sarcoidosis, carcinomatous or infectious meningitis, GBS/Miller Fisher Syndrome, myasthenia gravis, leprosy, leukemia/lymphoma
• Acute otitis media
• Bell’s Palsy: Antiviral agents (most commonly acyclovir or valacyclovir)
– Incomplete facial motor function recovery at 1 year:
Antivirals versus (vs.) placebo: No significant difference: Relative Rate (RR): 0.88 (1)[A]
Antivirals and corticosteroids versus placebo: Significantly better outcomes: RR: 0.56 (1)[A]
Adverse events (antivirals vs placebo): No significant differences: RR: 1.06
Conclusions: Antivirals versus placebo: Do not enhance complete functional recovery (high quality); antivirals versus corticosteroids: Significantly less likely to produce complete recovery (moderate quality) (1)[A]
• Bell’s Palsy: Corticosteroids
– Incomplete facial motor function recovery ≥6 months:
Corticosteroids 23%, Placebo 33%; RR 0.71 (2)[A]
Motor synkinesis was significantly reduced with corticosteroids versus placebo: RR 0.6 (2)[A]
Conclusion: Evidence reveals significant benefit from corticosteroids (2)[A]
– Early initiation of corticosteroids is of benefit:
Sullivan et al. (3)[A]: Prednisolone 25 mg b.i.d for 10 days
Engstrom et al. (4)[A]: Prednisolone 60 mg daily × 5 days followed by 10 mg/day taper over 5 days
Antiviral therapy has no proven benefit; some practitioners recommend use in severe or complete palsies.
• Ophthalmic concerns: Prevention of exposure keratitis and corneal injury
– Lubrication: Artificial tears, methylcellulose-based ointment, eye patching, and/or moisture chamber qhs.
– Surgical management required with potential or ongoing corneal injury.
Issues for Referral
• Corneal exposure
• Acute nerve trauma or transection: Consider primary neurorrhaphy
COMPLEMENTARY & ALTERNATIVE THERAPIES
Acupuncture and physical therapy lack adequate evidence.
• Facial nerve decompression lacks sufficient evidence (5)
• Surgical management: Corneal sequela
– Gold weight implant (upper lid) or tarsorrhaphy
For incomplete eyelid closure
Prevents and treats corneal injury
• Idiopathic/uncomplicated cases: 1–2 weeks, thereafter as appropriate.
• Corneal exposure requires ophthalmic monitoring.
– Corneal status dictates frequency: Initial daily follow-up required for corneal breakdown or ulceration.
Diabetics: Serum glucose monitoring during steroid therapy.
Prevention and symptoms of corneal injury
• Bell’s Palsy: Functional recovery excellent in >80%
– Improved functional outcomes with incomplete palsies and early onset recovery (<3 weeks)
– More complete palsies: Higher likelihood of incomplete recovery and aberrant regeneration
– Poorer prognosis: Hyperacusis, decreased tearing, hypertension, age >60 years, diabetes, psychiatric disease, pregnancy
• Recovery dependent on site and extent of nerve injury
• EMG and nerve conduction studies: Preservation of motor amplitudes indicates axonal continuity and suggests good prognosis for recovery.
• Neoplastic and congenital etiologies associated with incomplete recovery
• Aberrant regeneration resulting in: Motor Synkinesis or Crocodile Tears
• Hemifacial Spasm
• Treatment: Chemodenervation with botulinum toxin
1. Lockhart P, Daly F, Pitkethly M, et al. Antiviral treatment for Bell’s palsy (idiopathic facial paralysis). Cochrane Database Syst Rev 2009; (4): CD001869. [A]
2. Salinas RA, Alvarez G, Daly F, et al. Corticosteroids for Bell’s palsy (idiopathic facial paralysis). Cochrane Database Syst Rev 2010;(3):CD001942. [A]
3. Sullivan FM, Swan IRC, Donnan PT, et al. Early treatment with prednisolone or acyclovir in Bell’s Palsy. N Engl J Med 2007;357:1598–1607. [A]
4. Engstrom M, Berg T, Stjernquist-Desatnik A, et al. Prednisolone and valaciclovir in Bell’s palsy: A randomised, double-blind, placebo-controlled, multicentre trial. Lancet Neurol 2008;7:993–1000. [A]
5. Grogan P, Gronseth GS. Practice parameter: Steroids, acyclovir, and surgery for Bell’s Palsy (an evidence-based review): Report of the Quality Standards Subcommittee of the AAN. Neurology 2001;56: 830–836.