Bell's Palsy: Symptoms, Causes, and Treatment

• Bell's palsy is an acute, idiopathic peripheral facial nerve (CN VII) palsy
• Results in unilateral facial weakness or paralysis
• It is the most common cause of facial paralysis
• Symptoms develop abruptly over 48-72 hours
• While often self-limiting, incomplete recovery occurs in about 30% of cases, meaning prompt intervention is needed
• Early treatment with corticosteroids improves outcomes and reduces complications, such as synkinesis
• Bell's palsy causes sudden, temporary weakness in your facial muscles
• This makes half of your face droop
• Your smile becomes one-sided, and your eye on the affected side resists closing
• Can occur at any age
• The exact cause is unknown
• Believed to be the result of swelling and inflammation of the CN VII (facial nerve) that controls the muscles on one side of your face
• In most cases the disease is temporary
• Symptoms improve in a few weeks with complete recovery in 6 months
• A few people have long-term symptoms and rarely it recurs
• The Facial Nerve (CN VII) passes through a narrow corridor of bone on its way to your face.
• Facial weakness or paralysis may cause one corner of your mouth to droop, and you may have trouble retaining saliva on that side of your mouth.
• It may also make it difficult to close the eye on the affected side of your face.

Etiology

• Arises from inflammation and compression of the facial nerve within the bony facial canal
• Likely triggered by viral reactivation (e.g., HSV-1)
• Ischemia from microvascular dysfunction (e.g., diabetes, hypertension) may exacerbate nerve injury
• Autoimmune mechanisms and environmental factors (e.g., pregnancy, cold exposure) may also contribute
• Secondary causes like Lyme disease or tumors must be excluded
• In acute, there is inflammation of the facial nerve with mononuclear cells, consistent with an infectious or immune cause
• Herpes simplex virus (HSV) type 1 DNA was frequently detected in endoneurial fluid and posterior auricular muscle, suggesting reactivation of this virus
• Reactivation of varicella-zoster virus is associated with the disease in up to one-third of cases and may represent the second most frequent cause
• A variety of other viruses have also been implicated less commonly
• can be observed in the setting of human immunodeficiency virus (HIV) seroconversion

Incidence

• Annual incidence: 15-30 cases per 100,000
• 40,000 cases per year in the U.S.
• Higher rates in pregnancy (third trimester) and individuals with diabetes
• Lifetime risk: 1 in 60

Risk Factors

• Diabetes: Microvascular ischemia increases nerve vulnerability
• Pregnancy: Hormonal changes and fluid retention elevate risk
• Hypertension: Linked to poorer recovery and recurrence
• The exact cause remains unknown
• Often related to a Viral illness

Viral Illnesses Common

• Herpes simplex (I and II)
• Herpes zoster
• Epstein-Barr
• Cytomegalovirus
• Adenovirus
• Mumps
• Rubella
• Influenza B
• Coxsackievirus
• Lyme's disease (bacterial)

Prevention

• Manage chronic conditions (diabetes, hypertension)
• Avoid cold exposure and viral triggers
• No specific immunizations, though HSV vaccination research is ongoing

Clinical Manifestations

• Sudden unilateral facial weakness: Inability to close the eye, smile symmetrically, or raise the eyebrow (House-Brackmann Grade II-VI)
• Lagophthalmos: Incomplete eyelid closure causing corneal dryness
• Hyperacusis: Sound sensitivity due to stapedius muscle dysfunction
• Loss of taste: Anterior 2/3 of the tongue (chorda tympani involvement)
• Post-auricular pain: Precedes paralysis in 60% of cases
• Sudden onset of mild weakness to total paralysis on one side of the face
• Drooling
• Postauricular pain - pain around the jaw or in or behind the ear on the affected side
• Headache
• A decrease in taste
• Changes in the production of tears and saliva
• The onset is fairly abrupt, with maximal weakness being attained by 48 hours as a general rule
• Pain behind the ear may precede the paralysis for a day or two
• Taste sensation may be lost unilaterally, and hyperacusis may be present
• In some cases, there is mild cerebrospinal fluid lymphocytosis
• MRI may reveal swelling and uniform enhancement of the geniculate ganglion and facial nerve and, in some cases, entrapment of the swollen nerve in the temporal bone
• Approximately 80% of patients recover within a few weeks or months
• Electromyography may be of some prognostic value: evidence of denervation after 10 days indicates there has been axonal degeneration, that there will be a long delay (3 months as a rule) before regeneration occurs, and that it may be incomplete
• The presence of incomplete paralysis in the first week is the most favorable prognostic sign
• Recurrences are reported in about 7% of cases

Review Of Systems

• Neurological: Facial asymmetry, difficulty blinking, speech changes
• Ophthalmological: Dry eye, excessive tearing
• Otolaryngological: Ear pain, hyperacusis
• Gastrointestinal: Altered taste, drooling
• Dermatological: Flattened nasolabial fold

Physical Assessment Findings

• Unilateral facial drooping: Asymmetric smile and forehead wrinkling
• Bell's phenomenon: Upward eye deviation on attempted closure
• Reduced corneal reflex: Due to orbicularis oculi weakness
• Taste impairment: Tested with sweet/salty substances on anterior tongue
• Intact forehead movement: Differentiates from central causes (e.g., stroke)

Assessment Tools & Grading

• Observe for facial asymmetry including smile, nasolabial folds, blinking
• General Exam including otoscopy, palpation of masses near neck and face, and skin exam
• Assessment of Motor Function -
• Raise eyebrows, close eyes tightly, smile, puff out cheeks, purse lips, grimace (show upper and lower teeth)
• Assess sensory function measuring sensation of the face and ears, taste sensation to the anterior 2/3rd of tongue
• Assess Reflexes - Orbicularis reflex: tap the glabella and observe for asymmetry in blink pattern; Bell Phenomenon: observe upward movement of eyes during forced eye closure
• House-Brackmann Scale: Grades severity from I (normal) to VI (total paralysis)
• Sunnybrook Facial Grading System: Quantifies symmetry and movement

High Yield Questions to Ask Patient

• Did symptoms develop suddenly (≤72 hours)?
• Any recent viral illness, tick exposure, or trauma?
• Pain behind the ear before weakness?
• Difficulty closing one eye or tasting food?
• History of diabetes, hypertension, or pregnancy?
• Prior episodes of facial weakness?
• Recent weight loss, fever, or rash (e.g., Lyme, Ramsay Hunt)?
• Exposure to loud noises worsening symptoms?
• Current medications (e.g., antivirals, steroids)?
• Family history of autoimmune disorders?

Clinical Algorithms

• Acute Evaluation:
• Rule out stroke (forehead sparing? MRI/CT)
• Check for vesicular rash (Ramsay Hunt) or tick exposure (Lyme serology)
• Assess House-Brackmann grade
• Management:
• Start steroids within 72 hours
• Add antivirals if HSV/VZV suspected
• Refer refractory cases to neurology

Treatment Prioritization

• Corticosteroids: Prednisone 60 mg/day × 5 days, then 5-day taper
• Eye protection: Artificial tears, nighttime ointment, patching
• Antivirals: Valacyclovir 1 g TID × 7 days if HSV/VZV suspected
• Physical therapy: Facial exercises to prevent contractures
• Symptomatic measures:
• The use of paper tape to depress the upper eyelid during sleep and prevent corneal drying
• Artificial tears
• Massage of the weakened muscles
• A course of glucocorticoids, given as prednisone 60-80 mg daily during the first 5 days and then tapered over the next 5 days, modestly shortens the recovery period and improves the functional outcome
• Large and well-controlled randomized trials found no added benefit of the antiviral agents valacyclovir (1000 mg daily for 5-7 days) or acyclovir (400 mg five times daily for 10 days) compared to glucocorticoids alone
• Either of these agents should be used if vesicular lesions are observed in the palate or external auditor canal
• For patients with permanent paralysis from the disease, a number of cosmetic surgical procedures have been used to restore a relatively symmetric appearance to the face

Nonpharmacological Management

• Eye care: Lubricating drops hourly, moisture chamber goggles
• Facial massage: Prevents muscle atrophy
• Neuromuscular retraining: Improves symmetry
• Eye protection
• MOST IMPORTANT: Eye patch at night, lubricant eye drops every 2 hours, protective glasses; Physical therapy to restore muscle strength
• Facial Massage – warm moist compresses
• Acupuncture

Pharmacological Management

• 1st Line: Prednisone or prednisolone 60-80 mg PO daily × 5 days, taper by 10mg/day for at least 10 days
• 2nd Line: Valacyclovir 1 g PO TID × 7 days (if HSV/VZV suspected)
• Adjuncts: Artificial tears (carboxymethylcellulose), lubricating ointment (lanolin)
• Steroids (maximum benefit when started within 72 hours - Prednisone or Prednisolone 60-80mg for 5 days with taper by 10mg/ day for a total of at least 10 days
• Antivirals (in conjunction with Steroids)
• Tapered dosage of corticosteroids (must be initiated within 3 days of onset or little benefit)
• Studies are limited for treatment in children younger than 16 years
• Children have higher rates of spontaneous recovery than adults
• Valacyclovir is first line due to superior bioavailability and ease of administration
• Oral antiviral agents plus oral corticosteroids for patients with House-Brackmann grade IV or higher
• Eye Care:
• Artificial tears (liquid or gel): applied every hour while awake
• Ointment with mineral oil and white petrolatum (e.g., Soothe) applied at night
• Aspirin, acetaminophen, ibuprofen for pain relief
• Cautious use of steroids in pregnancy
• Monitor blood pressure for hypertensive disorder

Differentiation

• Guilian-Barré presents with Ascending paralysis and areflexia -- Diagnostic test is Lumbar puncture, EMG
• Lyme Disease presents with Erythema migrans, bilateral palsy -- Diagnostic test is Lyme serology
• Ramsay Hunt Syndrome presents with Vesicular rash, ear pain -- Diagnostic test is VZV PCR
• Stroke presents with Forehead sparing, focal deficits -- Diagnostic test is MRI brain
• Parotid Tumor presents with Progressive weakness, mass on imaging -- Diagnostic test is CT/MRI with contrast

Consultation/Referral

• Neurology: Atypical features or no improvement at 3 weeks
• Ophthalmology: Persistent lagophthalmos/corneal ulceration
• ENT: Surgical decompression if refractory (rare)
• Ophthalmology – eye complications i.e.: corneal abrasion
• Neurology - for CNS involvement or if suspected
• Neurosurgery - decompressive surgery for those with 90% nerve compression
• Otolaryngology – Botox injections if not resolved in 3 months

Initial Diagnosis Patient Guidance

• Reassure 70% recover fully within 6 months
• Eye care: Demonstrate artificial tears and patching
• Medication adherence: Stress steroid taper completion
• Follow-up: Schedule at 1 and 3 weeks

Risk Stratification

• Low risk: House-Brackmann Grade II-III, no comorbidities
• High risk: Grade IV-VI, diabetes, or pregnancy

Follow Up

• 1 week: Assess steroid response, eye integrity
• 1 month: EMG if no improvement
• 3-6 months: Evaluate for synkinesis

Expected Course

• 85% show improvement within 3 weeks
• Full recovery in 70% by 6 months
• 5% of patients will have severe sequalae which can include:
• Facial asymmetry
• Vision loss
• Hearing loss
• Tinnitus
• Poorer prognosis with complete paralysis, age >60, or hypertension

Possible Complications

• Corneal ulceration: From exposure keratopathy
• Synkinesis: Aberrant nerve regeneration causing involuntary movements
• Chronic facial asymmetry: Affects 5-10%

Key Pearls

• "Forehead sparing” suggests central pathology (e.g., stroke)
• Steroids within 72 hours improve recovery by 14%
• House-Brackmann Grade ≥IV predicts incomplete recovery