Basics
Description
- Acute, idiopathic peripheral CN VII (facial nerve) palsy
- Complete recovery in 85% of cases without treatment
- Degree of deficit correlates with prognosis:
- Complete lesions have poorest prognosis
- Partial lesions often have excellent results
- Recovery usually begins within 2 wk (often taste returns 1st) and is complete by 2-3 mo:
- Advanced age and slow recovery are poor prognosticators
- Affects men and women equally
- Age predominance between the 3rd and 5th decade (may occur at any age)
- Diabetes and pregnancy increase risk
- Incidence 15-40 per 100,000 per year
- The most common cause of facial nerve palsy in children
Etiology
- Idiopathic by definition, but viral cause (particularly herpes simplex) suspected
- Lyme disease, infectious mononucleosis (Epstein-Barr virus [EBV] infection), varicella-zoster infections, and others may cause peripheral 7th nerve palsy
- Mechanism: Edema and nerve degeneration within stylomastoid foramen
- Innervation to each side of forehead is from both motor cortices:
- Unilateral cortical processes do not completely disrupt motor activity of forehead
- Only peripheral or brainstem lesion can interrupt motor function of just 1 side of forehead
Diagnosis
Signs and Symptoms
History
Sudden onset of unilateral facial droop, incomplete eyelid closure, and loss of forehead muscle tone:
- Maximal deficit by 5 days in almost all cases (2 days in 50%)
- Tearing (68%) or dryness of eye (16%) and less frequent blinking on affected side
- Subjective "numbness" of the affected side
- Abnormal taste, drooling
- Hyperacusis (sensitivity to loud sounds)
- Fullness or pain behind mastoid
- Viral prodrome frequently reported
Physical Exam
- Unilateral facial palsy including the forehead
- If forehead muscle tone is not lost, a central lesion is strongly implied (i.e., this is not Bells palsy)
- Motor weakness isolated to 7th nerve distribution:
- Involves both upper and lower face
- An otherwise normal neurologic exam including all cranial nerves and extremity motor function
- The Bell phenomenon (upward rolling of the eye on attempted lid closure) may be seen
Essential Workup
Diagnosis is clinical and based on history and physical exam
Diagnosis Tests & Interpretation
Lab
- Not helpful in diagnosis of Bells palsy
- Lyme titers are useful when Lyme disease is suspected or in endemic area
- Tests for mononucleosis (CBC, monospot) if EBV infection suspected
Imaging
- Not helpful in diagnosis of Bells palsy unless a parotid tumor, mastoiditis, etc. are suspected
Differential Diagnosis
- Brainstem events (mass, bleed, infarct) affecting CN VII almost always involve CN VI (abnormal EOM) and may affect long motor tracts:
- There have been (rare) case reports of isolated CN VII palsy from brainstem disease.
- Lyme disease: History of tick bite, erythema migrans rash, or endemic area
- Zoster (Ramsay Hunt syndrome): Look for herpetic vesicles, inquire about tinnitus or vertigo
- Infectious mononucleosis: Look for pharyngitis, posterior cervical adenopathy
- Tumors: Parotid, bone, or metastatic masses, acoustic neuroma (deafness)
- Trauma: Skull fracture or penetrating facial injury may damage CN VII
- Middle ear or mastoid surgery or infection, cholesteatoma
- Meningeal infection
- Guillain-Barr © syndrome: Other neurologic deficits are present (e.g., ascending motor weakness or diminished deep tendon reflexes [DTRs])
- Basilar artery aneurysm; other CN deficits should be present
- Bilateral peripheral CN VII palsy: Consider multiple sclerosis, sarcoidosis, leukemia, and Guillain-Barr ©. Idiopathic (Bells) palsy may be bilateral in rare cases
- Early HIV infection
- Bell's palsy may reoccur; treatment is unchanged
Treatment
Pre-Hospital
None
Initial Stabilization/Therapy
Patients with an isolated peripheral CN VII palsy are stable.
Ed Treatment/Procedures
- Corneal damage may result from incomplete eyelid closure:
- Lubricating and hydrating ophthalmic preparations are often needed
- Eye patching at night
- Oral steroids may hasten recovery if started within 1 wk of onset (preferably w/in 72 hr):
- Complications of therapy are rare
- Antiviral therapy (acyclovir or valacyclovir) with steroids may be effective in improving functional nerve recovery:
- Initiate within 72 hr of symptom onset
- No clear proven benefit
- May be indicated for severe palsy
- Suspected Lyme disease should be treated with doxycycline or amoxicillin
- Surgical decompression may be indicated for complete lesions that do not improve; this is controversial
Medication
First Line
- Lacri-Lube or artificial tears: At bedtime and PRN; dryness/irritation in affected eye (or equivalent)
- Prednisone: 30-40 mg PO BID for 7 days, (peds: 2 mg/kg/d PO [max. 60 mg])
Second Line
Valacyclovir 1 g PO TID for 7 days (peds: 20 mg/kg TID) may be useful in severe cases.
Follow-Up
Disposition
Admission Criteria
Isolated peripheral CN VII palsy does not require admission.
Discharge Criteria
Isolated peripheral CN VII palsy may be treated on outpatient basis.
Followup Recommendations
Follow-up should be within 1 wk.
Pearls and Pitfalls
- Motor weakness isolated to 7th nerve distribution:
- Involves both upper and lower face
- If tone is NOT lost on the forehead, it is not Bells palsy.
- Otherwise normal neurologic exam including all cranial nerves and extremity motor function
- Protect the eye
- Steroids beneficial, antivirals controversial
Additional Reading
- de Almeida JR, Al Khabori M, Guyatt GH, et al. Combined corticosteroid and antiviral treatment for Bells palsy: A systematic review and meta-analysis. JAMA. 2009;302:985-993.
- Engstr ¶m 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.
- Gilden DH. Bell's palsy. N Engl J Med. 2004;351:1323-1331.
- Gilden DH, Tyler KL. Bell's palsy-Is glucocorticoid treatment enough? N Engl J Med. 2007;357:1653-1655.
- Hato N, Yamada H, Kohno H, et al. Valacyclovir and prednisolone treatment for Bell's palsy: A multicenter, randomized, placebo-controlled study. Otol Neurotol. 2007;28:408-413.
- Sullivan FM, Swan IR, Donnan PT, et al. Early treatment with prednisolone or acyclovir in Bell's palsy. N Engl J Med. 2007;357:1598-1607.
- Wang CH, Chang YC, Shih HM, et al. Facial palsy in children: Emergency department management and outcome. Pediatr Emerg Care. 2010;26:121-125.
Codes
ICD9
351.0 Bells palsy
ICD10
G51.0 Bells palsy
SNOMED
- 193093009 Bells palsy (disorder)