Bell Palsy The 5 Minute Pediatric Consult


	Bell Palsy

Debra Boyer

Database
Differential Diagnosis
Data Gathering
Physical Examination
Laboratory Aids
Therapy
Follow-Up
Common Questions and Answers
Bibliography

DATABASE

DEFINITION

An acute, unilateral palsy of the upper and lower musculature of the face due to involvement of the facial nerve.

Many cases are likely secondary to a virally induced neuritis. Causative agents include herpes simplex virus (HSV), varicella-zoster virus (VZV), Epstein-Barr virus (EBV), and coxsackie, influenza, and mumps viruses.
Other cases may occur as a result of trauma or Lyme disease.
Ramsay Hunt syndrome: characterized by unilateral facial paralysis and severe otalgia, associated with the appearance of a periauricular/auricular vesicular eruption (12% of all facial paralysis).

PATHOPHYSIOLOGY

Facial nerve (Cranial Nerve VII) has motor, sensory, and autonomic components.
In viral infections, viral reactivation followed by replication within the ganglion cells leads to inflammation of Schwann cells. Ultimately, an autoimmune response leads to demyelinization and hypofunction of the involved nerve.
Blunt trauma to the temporal bone/mastoid area can also directly injure the facial nerve.

EPIDEMIOLOGY

Incidence is 2.7 per 100,000 in children less than 10 years of age; and 10.1 per 100,000 in children 10 to 20 years of age.
In children 10 to 20 years of age, girls are affected twice as much as boys.
Less than 1% of cases are bilateral.
The recurrence rate is 10%.

COMPLICATIONS

Corneal abrasions
Keratitis
Facial contractures
Synkinesis
Facial tics
Gustatory tearing (crocodile tears)
Recurrent facial palsy (should cause one to reconsider the diagnosis)

PROGNOSIS

More than 60% of children will recover completely.
Improvement in symptoms usually begins within 2 to 4 weeks, and reaches its maximum within 6 to 12 months.
Facial paralysis associated with Ramsay Hunt syndrome has a worse prognosis. In patients with complete paralysis, only 10% will recover normal facial function. Among those with incomplete paralysis, only 66% will recover completely. The simultaneous onset of paralysis and the vesicular eruption is a negative prognostic sign.

DIFFERENTIAL DIAGNOSIS

CONGENITAL

Möbius syndrome
Congenital unilateral lower-lip paralysis (CULLP)
Hemifacial microsomia
Aural atresia/microtia
Chiari malformation

ENVIRONMENTAL

Teratogenesis (drugs, infectious agents)

INFECTIOUS

Acute otitis media
Chronic otitis media
Lyme disease
Epstein-Barr virus
Mycoplasma pneumoniae infection
Mastoiditis: bacterial, tuberculosis
Osteomyelitis of the skull

TRAUMA

Birth trauma, including damage due to forceps assistance
Temporal bone fractures
Penetrating head/neck wounds
Iatrogenic injury during otologic surgery

NEOPLASTIC

Astrocytoma
Medulloblastoma
Pontine glioma
Parotid gland tumors

METABOLIC

Hyperparathyroidism
Hypothyroidism
Osteopetrosis
Idiopathic infantile hypercalcemia

IMMUNOLOGIC/INFLAMMATORY

Guillain-Barré syndrome
Sarcoidosis
Multiple sclerosis
Myasthenia gravis

MISCELLANEOUS

Melkersson-Rosenthal syndrome: recurrent swelling of the lips/face, intermittent facial nerve paralysis, and fissured tongue (lingua plicata)

DATA GATHERING

HISTORY

Birth history: mode of delivery, associated trauma?
Ask about preceding viral illness.
Early symptoms may include facial numbness, watery eyes or decreased tearing, facial pain, impairment of taste, and hyperacusis.
Difficulty hearing
History of trauma
Acute versus chronic onset (Bell palsy is usually acute)
Tick exposures

PHYSICAL EXAMINATION

Differentiate central from peripheral facial nerve palsy. The forehead muscles are innervated by both cerebral hemispheres via nerve fibers traveling in each peripheral facial nerve. Therefore, central lesions will cause paralysis of only the lower face. Peripheral lesions will involve both the upper and the lower face.
Involvement of other cranial nerves
Complete neurologic examination
Rash (periauricular vesicles seen in Ramsay Hunt syndrome)
Evaluate for acute/chronic otitis media

LABORATORY AIDS

Lyme titers, especially if living in an endemic area
Lumbar puncture: usually not indicated with an isolated CN VII palsy. However, should be performed if neurologic examination is abnormal (aside from CN VII) or if meningitis/encephalitis is suspected.

RADIOGRAPHIC AND OTHER STUDIES

Head magnetic resonance imaging (MRI): only indicated if neurologic examination is abnormal aside from CN VII palsy.
Electrodiagnostic testing (nerve excitability, facial nerve latency, and electroneuronography) can determine the rate/severity of neural degeneration distal to the site of injury. It is most often used after a traumatic facial nerve injury to determine the timing of surgical exploration. It must be done more than 72 hours from the development of paralysis.
Modified tear test: used to determine the ability for tear production, between the affected and unaffected eye. Involves a 1-minute filter paper measurement of tear production after ammonia fume exposure. It is indicated if spontaneous tear production is not witnessed.
Stapedial reflex: only useful if the tympanic membrane is normal. Impedance is measured after an intense sound stimulation. An intact stapedial reflex indicates paralysis is incomplete, predicting a better prognosis.

THERAPY

Prednisone (2 mg/kg/day): the mainstay of therapy. Studies have shown better prognosis when steroids are used in both idiopathic Bell palsy and HSV-related facial nerve palsy. Prognosis is better with earlier onset of therapy. Most would treat with a 10-day course, with a tapering dose over the last few days. Reevaluate the patient after 5 to 6 days to ensure that the symptoms are not progressing.
Acyclovir (p.o.): should be started in patients with Ramsay Hunt syndrome, usually as a 10-day course. Some studies advocate its use in all cases of idiopathic Bell palsy, in conjunction with p.o. prednisone.
Antibiotics: to treat otitis media, Lyme disease, if applicable
Eye care: the eye must be protected during the day with “artificial tears,” (e.g., Tears Naturale) and with an ointment (e.g., Lacri-Lube) at night.
Facial nerve decompression: not often recommended, because Bell palsy is not an entrapment syndrome.
Electrotherapy: electrical stimulation of the paralyzed muscles is not recommended. It may actually slow the growth of neurofibrils.

FOLLOW-UP

Patients should be reevaluated on days 5 to 6. If progression of the paralysis has occurred, the diagnosis of Bell palsy should be reconsidered.
Stapedial reflex: returns less than 3 weeks after onset of the paralysis; indicates that facial nerve function is returning.
Maximal nerve excitability stimulation test: can be used to help indicate prognosis. It is only useful during the first few weeks; thereafter, degeneration occurs, making the test inaccurate.

PITFALLS

Waiting to start therapy (prednisone/acyclovir). If therapy is delayed, a patient with severe disease may develop irreversible nerve damage.
Failing to consider a different diagnosis with either prolonged or recurrent facial paralysis.

PREVENTION

Currently, there are no preventative strategies for Bell palsy.

COMMON QUESTIONS AND ANSWERS

Q: Should acyclovir be started only in those patients with vesicular eruptions?
A: Certainly, acyclovir should be given to all children with facial palsy and a periauricular vesicular eruption. In addition, severe pain may be an indication of zoster, and acyclovir should be given. Studies have also indicated that empiric treatment with prednisone and acyclovir in idiopathic facial palsy did result in a better return of facial function.

Q: What should be considered with recurrent facial palsy?
A: Recurrent, unilateral facial palsy requires the physician to search for an alternate diagnosis. Neoplasms, vascular malformations, sarcoidosis, diabetes, and infectious mononucleosis should all be considered. One should also consider Melkersson-Rosenthal syndrome with recurrent paralysis.

ICD-9-CM 351.0

BIBLIOGRAPHY

Adour K. Medical management of idiopathic (Bell’s) palsy. Otolaryngol Clin North Am 1991;24(3):663–673.

Bauer C, Coker N. Update on facial nerve disorders. Otolaryngol Clin North Am 1996;29(3):445–454.

Orobello P. Congenital and acquired facial nerve paralysis in children. Otolaryngol Clin North Am 1991;24(3):647–651.

Smith S. Pediatric neurologic diseases, 2nd ed. St. Louis: Mosby, 1994.

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