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Bell's palsy



Bell's palsy, also known as idiopathic facial paralysis, is an acute-onset, isolated, unilateral, lower motor neurone facial weakness/paralysis.
The exact cause of Bell's palsy is unknown; however, reactivation of herpes virus at the geniculate ganglion of the facial nerve has been postulated.
Disease course
The likely vascular distension, inflammation, and edema with ischemia of the facial nerve results in Bell's palsy, which presents with clinical manifestations of unilateral weakness/paralysis of upper and lower facial muscles, drooping of ipsilateral eyelids, dry eye due to inability to close eyes completely, epiphora, drooping of the corner of the mouth, ipsilateral impaired/loss of taste sensation, difficulty in eating, dribbling of saliva, altered sensation on the affected side of the face, pain in or behind the ear, hyperacusis on the affected side if stapedius muscle is involved. Spontaneous complete recovery occurs in 70-75% of untreated patients.
Prognosis and risk of recurrence
Bell's palsy is not associated with an increased risk of mortality.


Key sources

The following summarized guidelines for the evaluation and management of Bell's palsy are prepared by our editorial team based on guidelines from the French Society of Otorhinolaryngology (SFORL 2020), the American Academy of Otolaryngology-Head and Neck Surgery Foundation (AAO-HNSF 2013), and the American Academy of Neurology (AAN 2012). ...
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Screening and diagnosis

Differential diagnosis
As per SFORL 2020 guidelines:
Question the diagnosis of Bell's palsy and screen for tumoral causes in patients with peripheral facial palsy progressing beyond 72 hours after onset or showing fluctuation or recurrence or bilateral involvement.
Question the diagnosis of Bell's palsy in patients with peripheral facial palsy associated with abnormal otoscopy or parotid or cervical lymph node palpation or ipsilateral hearing loss, dizziness or other neurological signs.
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Classification and risk stratification

Severity assessment: as per SFORL 2020 guidelines, assess the severity of facial involvement on a standardized grading system (House-Brackmann classification) for inclusion in the medical file during the initial work-up of patients with Bell's palsy.
House-Brackmann facial paralysis scale
Patients characteristics
Normal facial function in all areas
Slight weakness on close inspection; mouth: slight asymmetry, forehead: moderate to good function; eye: complete closure with minimum effort; normal symmetry and tone at rest
Obvious but not disfiguring weakness between 2 sides, noticeable but not severe synkinesis, contracture, and/or hemifacial spasm; mouth: slightly weak with maximum effort, forehead: slight to moderate movement, eye: complete closure with effort; normal symmetry and tone at rest
Obvious and disfiguring asymmetry; mouth: asymmetric with maximum effort, forehead: no motion, eye: incomplete closure; normal symmetry and tone at rest
Barely perceptible motion on contraction; mouth: slight movement, forehead: no motion, eye: incomplete closure; asymmetry at rest
Complete absence of any facial movement
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Diagnostic investigations

History and physical examination
As per SFORL 2020 guidelines:
Perform a clinical examination to confirm the peripheral nature of the facial palsy.
Perform a complete clinical neurological and ear, nose and throat examination with otoscopy and parotid and cervical palpation in patients presenting for peripheral facial palsy. Screen for involvement of the superior and inferior facial areas and absence of autonomic-voluntary dissociation to confirm peripheral status. Attempt to rule out involvement of the somatosensory and motor central pathways and other cranial nerves by neurological examination.

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  • Laboratory studies

  • Diagnostic imaging

  • Electrodiagnostic testing

  • Audiometry

  • Tympanometry

Medical management

As per SFORL 2020 guidelines:
Administer prednisolone or methylprednisolone in patients with Bell's palsy as early as possible - ideally, within 72 hours.
Use one of the following regimens for corticosteroids:
1 mg/kg/day for 7-10 days
2 mg/kg/day for 10 days in severe cases (House-Brackmann grade V or VI) unless contraindicated (Expert opinion)

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  • Antiviral therapy

Nonpharmacologic interventions

Eye care: as per SFORL 2020 guidelines, advise eye care including local care, nocturnal occlusion and provide patient education, as early as possible. Refer patients with painful red eye to an ophthalmologist. Perform ophthalmologic monitoring for several weeks once recovery has begun.

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  • Acupuncture

  • Physical therapy

  • Physical therapy

Therapeutic procedures

Intratympanic corticosteroids: as per SFORL 2020 guidelines, do not offer intratympanic corticosteroids as a sole treatment for patients with Bell's palsy.

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  • Hyperbaric oxygen therapy

Surgical interventions

Facial nerve decompression: as per SFORL 2020 guidelines, insufficient evidence to support facial nerve decompression in patients with acute Bell's palsy.
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Specific circumstances

Patients with Ramsay-Hunt syndrome: as per SFORL 2020 guidelines, complete a 7-day therapy with prednisolone or methylprednisolone in addition to antiviral treatment, initiated as early as possible, in patients with Ramsay-Hunt syndrome.

Follow-up and surveillance

Indications for specialist referral: as per AAO-HNSF 2013 guidelines, reassess or refer to a facial nerve specialist patients with Bell's palsy who meet any of the following criteria:
new or worsening neurologic findings at any point
ocular symptoms developing at any point
incomplete facial recovery 3 months after initial symptom onset.

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  • Follow-up surveillance