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Bell's Palsy, Emergency Medicine

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 prognosisPartial 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 neededEye 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 onsetNo clear proven benefitMay 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 faceIf 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)