Bell’s Palsy
Jill C. Cash and Karen M. Kress
Definition
A.Bell’s palsy, also known as idiopathic peripheral facial palsy, is characterized by an acute onset of unilateral facial paralysis. The facial nerve affected is the seventh cranial nerve (CN), which travels in the skull beneath the ear to the muscles on each side of the face. Each facial nerve controls the muscles that control eye blinking and closing and facial expressions such as smiling and taste sensations from the tongue. Bell’s palsy affects only one of the paired facial nerves, but in rare cases, it can affect both sides.
Incidence
A.Bell’s palsy has an incidence of 40,000 Americans a year. It accounts for approximately 75% of all cases of facial paralysis. Approximately 5% of those affected experience recurrence. Both sexes are affected, as well as all ages, but most patients are in their middle years, older than 30 years. Fewer cases are noted prior to the age of 15 years and after the age of 60 years.
Pathogenesis
A.The pathogenesis of Bell’s palsy is unknown, but some possible etiologies include genetic, metabolic, autoimmune, and vascular causes. An increasing body of evidence reveals that Bell’s palsy may be a virally induced neuritis. A triggering event or stressor induces activation of a latent virus, most likely herpes simplex virus or herpes zoster virus, present within the geniculate ganglion of the facial nerve. Viral activation results in reexpression of dormant viral particles and neural inflammation, leading to entrapment, ischemia, and degeneration of the facial nerve.
Predisposing Factors
A.Diabetes.
B.Pregnancy.
C.Recent infection.
D.Positive family history.
E.Hypertension (HTN).
F.Hypothyroidism.
Common Complaints
A.Acute onset of unilateral facial weakness with inability to close one eye.
B.Sagging of one eyebrow.
C.Loss of nasolabial fold.
D.Mouth drawn to affected side.
Other Signs and Symptoms
A.Ipsilateral retroauricular pain with or preceding paralysis.
B.Hyperacusis or hypersensitivity to sound.
C.Dysgeusia, or perversion of taste, in the anterior two-thirds of the tongue.
D.Facial paresthesia.
E.Drooling.
F.Decreased tearing.
Subjective Data
A.Elicit onset, duration, and course of symptoms.
B.Have the patient describe all neurologic symptoms present.
C.Note associated symptoms such as disruption of taste and disturbances in visual function or hearing.
D.Note predisposing factors such as trauma, infection, or pregnancy.
E.Review the patient’s family history for presence of Bell’s palsy.
F.Review the patient’s medical history; especially note cerebrovascular or cardiac risk factors. A focused history should include contraindications to use of steroids.
Physical Examination
A.Check temperature (if indicated), blood pressure, pulse, and respirations.
B.Inspect:
1.Note facial appearance.
2.Observe symmetry of eyes. Check corneal reflex (decreased). Assess ears, nose, and throat; assess the skin for lesions. Assess in and behind ears for zosteriform lesions.
3.Complete ear exam to rule out infection.
4.Assess paralysis of all the muscles supplied by one facial nerve. Paralysis may be of varying degrees and need not be complete.
C.Auscultate: Auscultate the heart and lungs.
D.Neurologic exam: Perform a complete neurologic exam; test all CNs.
Subjective decreased sensation may be present in the trigeminal distribution.
Diagnostic Tests
A.Lyme titer: Positive in patients with secondary facial weakness from Lyme disease.
B.Skull radiography, CT scan, or MRI: Negative in Bell’s palsy, but may show evidence of fracture line, bony erosion by infection or neoplasm, stroke, or tumor.
C.Electromyographic (EMG) studies: Occasionally performed to predict prognosis and progression. EMG is reserved for severe cases of paralysis lasting longer than 1 week.
D.Lumbar puncture (LP): Indicated only when other conditions are suspected. Cerebrospinal fluid (CSF) should be sent for cytology.
Differential Diagnoses
A.Bell’s palsy.
B.Sjögren’s syndrome.
C.Stroke.
D.Lyme disease.
E.Sarcoidosis.
F.Ramsay Hunt syndrome, herpes zoster oticus.
G.Acoustic neuroma.
H.Middle ear disease such as purulent otitis media or neoplasms.
I.Guillain–Barré syndrome (GBS).
J.Parotid gland tumor.
K.Carcinomatous meningitis.
Plan
A.General interventions:
1.The condition is usually short term (3–4 weeks) and may be managed with steroids and acetaminophen as needed for discomfort.
2.Physical therapy may be beneficial for muscle weakness and strengthening muscles.
3.Ensure the patient gets reassurance and emotional support.
B. 
See Section III: Patient Teaching Guide Bell’s Palsy
:
1.Provide eye protection by means of the following:
a.Apply methylcellulose drops as needed and ocular lubricant (Lacri-Lube) at bedtime and as needed.
b.Tape eye closed, especially at night to avoid drying effect.
c.Wear dark glasses when outdoors to minimize light exposure. May also be helpful indoors around bright overhead lights or lamps
2.Physical therapy may be beneficial.
3.Ensure that the patient gets reassurance and emotional support.
Recovery may take 3 to 6 months or longer and is complete in approximately 80% of the cases.
C.Pharmaceutical therapy.
1.Prednisone: Adults take 80 mg every day with breakfast for first 3 days, then decrease dosage to 40 mg for 3 days, then to 20 mg daily for 3 days, then stop.
Recent studies suggest that a brief course of prednisone conveys modest benefits with minimal risks.
2.Use of oral acyclovir in conjunction with prednisone, at a dosage of 400 mg five times a day for 10 days. Consider acyclovir for patients without renal insufficiency and with no other contraindications to therapy. Valtrex 1 g twice a day for 7 to 10 days is also available.
3.Analgesics, such as acetaminophen, for ear pain or face pain.
Follow-Up
A.For patients with severe symptoms, follow up in 3 to 4 days, then again in 2 weeks.
B.If symptoms worsen or do not resolve within weeks, have the patient return to the clinic.
Consultation/Referral
A.Consult a neurologist for the following:
1.Failure to resolve significantly after 4 to 6 weeks. Only 5% to 8% report distressing residual signs and symptoms, including contracture of facial muscles at rest and synergistic mass innervation due to defective nerve regeneration, manifested as either crocodile tears secondary to abnormal secretory fibers intended for the salivary glands or ipsilateral eyelid shutting.
2.Other CN involvement or other abnormalities on neurologic exam.
3.Recurrence of facial palsy: About 5% to 7% of patients experience recurrence of symptoms. Known causes of recurrent palsy include sarcoidosis, diabetes, leukemia, and infectious mononucleosis.
4.Bilateral facial palsies.
B.Consult an ophthalmologist for persistent ocular pain or development of a corneal abrasion or ulceration.
C.Consult otolaryngologist if decompression treatment is considered.
Individual Considerations
A.Pregnancy: The incidence of Bell’s palsy is increased in pregnancy, with the highest incidence in the third trimester or immediately postpartum. May treat with prednisone during pregnancy.