BASICS

DESCRIPTION

• The facial nerve is the VII cranial nerve.

– Innervation:

– 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

EPIDEMIOLOGY

Incidence

11–40/100,000 per year (1)[A]; more common ages 15–45 years

Prevalence

None recently reported

RISK FACTORS

Bell’s Palsy: Pregnancy, diabetes, influenza, upper respiratory infection

Genetics

• 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

PATHOPHYSIOLOGY

Supranuclear, nuclear, infranuclear/peripheral dysfunction of the facial nerve

ETIOLOGY

Bell’s Palsy: Idiopathic, possible viral-associated inflammation and/or demyelination

COMMONLY ASSOCIATED CONDITIONS

None known; see risk factors.

DIAGNOSIS

HISTORY

• 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

PHYSICAL EXAM

• 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

Lab

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

Imaging

Initial approach

• 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

Diagnostic Procedures/Other

• 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)

Pathological Findings

Mobius syndrome: Aplasia/hypoplasia of cranial nerve nuclei

DIFFERENTIAL DIAGNOSIS

• Infectious, inflammatory/demyelinating, infiltrative, neoplastic/metastatic, compressive, traumatic, and idiopathic

– Supranuclear: Ischemia, mass lesion

– Nuclear: Pontine glioma, ischemia, hemorrhage, demyelination, vascular lesions

– Infranuclear

– 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

Pediatric Considerations

• Acute otitis media

TREATMENT

MEDICATION

• 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]

• Recommendations

– 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.

ADDITIONAL TREATMENT

General Measures

• 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.

SURGERY/OTHER PROCEDURES

• 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

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• 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.

Patient Monitoring

Diabetics: Serum glucose monitoring during steroid therapy.

PATIENT EDUCATION

Prevention and symptoms of corneal injury

PROGNOSIS

• 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.

Pediatric Considerations

• Neoplastic and congenital etiologies associated with incomplete recovery

COMPLICATIONS

• Aberrant regeneration resulting in: Motor Synkinesis or Crocodile Tears

• Hemifacial Spasm

• Treatment: Chemodenervation with botulinum toxin

Stay updated, free articles. Join our Telegram channel

Join