Bell Palsy

Key Features

Essentials of Diagnosis

• Sudden onset of lower motor neuron facial palsy

• May have hyperacusis or impaired taste

• No other neurologic abnormalities

General Considerations

• Idiopathic lower motor neuron facial paresis

• Attributed to an inflammatory reaction of the facial nerve near the stylomastoid foramen or in the bony facial canal

• Reactivation of herpes simplex or varicella zoster virus has been postulated

• Common in pregnancy or in diabetes mellitus

Clinical Findings

Symptoms and Signs

• Generally comes on abruptly, but may worsen over 1 or 2 days

• Pain about the ear often precedes or accompanies the weakness but usually lasts for only a few days

• There may be ipsilateral restriction of eye closure and difficulty with eating and fine facial movements

• A disturbance of taste is common, owing to involvement of chorda tympani fibers, and hyperacusis due to involvement of fibers to the stapedius occurs occasionally

• Vesicles may be observed in the external ear canal in cases due to herpes zoster infection

Differential Diagnosis

• HIV-related facial neuropathies

• Lyme disease

• Sarcoidosis

• Ramsay Hunt syndrome (herpes zoster of geniculate ganglion)

• Acoustic neuroma

• Acute or chronic otitis media

• Malignant otitis externa

• Guillain-Barré syndrome

• Tumor, eg, parotid, temporal bone tumor

• Brainstem infarct

Diagnosis

• Clinical features are characteristic

• Electromyography and nerve excitability or conduction studies provide a guide to prognosis

Laboratory Tests

• To exclude other causes of facial neuropathy (see Differential Diagnosis)

Treatment

Medications

• Corticosteroids increase the chance of a complete recovery at 9–12 months by 12–15%

  • Prednisone 60 mg orally daily for 5 days followed by a 5-day taper or

  • Prednisolone 25 mg orally twice daily for 10 days

• It is helpful to protect the eye with lubricating drops (or lubricating ointment at night) and a patch if eye closure is not possible

• Acyclovir or valacyclovir is only indicated when there is evidence of herpetic vesicles in the external ear canal

Surgery

• There is no evidence that surgical procedures to decompress the facial nerve are of benefit

Therapeutic Procedures

• The management is controversial

• Approximately 60% of cases recover completely without treatment

• Physical therapy may improve facial function

Outcome

Prognosis

• Patients with clinically complete palsy when first seen are less likely to make a full recovery than those with an incomplete one

• A poor prognosis for recovery is also associated with advanced age, hyperacusis, and severe initial pain

Reference