Bell's palsy causes sudden facial paralysis on one side of the face. Symptoms include numbness, pain, an asymmetrical smile, tearing eye, or changes in taste or hearing. A neurological exam checks for weakness in facial expressions and other cranial nerves. Most cases recover fully within a few weeks with corticosteroids or antivirals if caused by herpes. Reassurance of the high recovery rate is important, while ruling out other causes like tumors that require different treatment.

1. Bell's palsy (Idiopathic Facial Paralysis)
Presentation
This condition creates a very frightening facial disfigurement. An adult
complains of sudden onset of "numbness," a feeling of fullness or
swelling, pain or some other change in sensation on one side of the face; a
crooked smile, mouth "drawing" or some other asymmetrical weakness of
facial muscles; an irritated, dry or tearing eye; drooling out of the corner of
the mouth; or changes in hearing or taste. Often there will have been a viral
illness one to three weeks before. Upon initial observation of the patient, it is
immediately apparent that he is alert and oriented, with a unilateral facial
paralysis that includes one side of the forehead.
What to do:
• Perform a thorough neurological examination of cranial and upper
cervical nerves, and limb strength, noting which are involved, and
whether unilaterally or bilaterally. Ask the patient to wrinkle the
forehead, close the eyes forcefully, smile, puff the cheeks and whistle,
observing closely for facial assymetry. Central or cerebral lesions result
in relative sparing of the forehead. Check tearing, ability to close the
eye and protect the cornea, corneal dessication, hearing, and, when
practical, taste. Examine the ear canals for herpetic vesicles and the
tympanic membrane for signs of otitis media or cholesteatoma.
Patients presenting with facial paralysis accompanied by acute otitis
media, chronic suppurative middle ear disease, otorrhea or otitis
externa require otolaryngologic consultation.
• If the cornea is dry or injured from the patient's inability to make tears
and blink, protect it by patching. If patching is not necessary, then
recommend wearing eyeglasses and applying methylcellulose artificial
tears regularly during the day and using a protective bland ointment at
night.
• If there is a history of head trauma, obtain a CT scan of the head
(including the skull base) to rule out a temporal bone fracture.
• If the diagnosis is clearly an early idiopathic cranial nerve palsy not
caused or complicated by trauma, infection, or diabetes, try to
ameliorate symptons with a short course of corticosteroids (e.g.,
prednisone 60mg qd, tapering after 5 days.)
• Send a serum specimen for acute phase Lyme disease titers, if
available, because this is another treatable disorder which can present
as a facial neuropathy. In areas where Lyme disease is endemic, a 10
day course of tetracycline or doxycycline may be indicated.
• If the etiology appears to be zoster-varicella (e.g., grouped vesicles on
the tongue) prescribe acyclovir or famcyclovir as for shigles.

2. • Reassure the patient that 70-80% of cases of Bell's palsy recover
completely in a few weeks, but provide for definite followup and
reevaluation.
• Provide appropriate specialty referral when there is a mass in the head
or neck or a history of any malignancy.
What not to do:
• Do not forget alternate causes of facial palsy which require different
treatment, such as cerebrovascular accidents and cerebellopontine
angle tumors (which usually produce weakness in limbs or defects of
adjacent cranial nerves), multiple sclerosis (which is usually not painful,
spares taste, and often produces intranuclear ophthalmoplegia),
Ramsay Hunt syndrome (or herpes zoster of the geniculate ganglion,
which causes decreased hearing, pain, and vesicles in the ear canal),
and polio (which presents as fever, headache, neck stiffness, and
palsies).
• Do not order a CT unless there is a history of trauma or the symptoms
are atypical and include such findings as vertigo. central neurological
signs, or severe headache.
• Do not make the diagnosis of Bell's palsy in patients who report
gradual onset of facial paralysis over several weeks or facial paralysis
that has persisted 3 months or more. These patients need further
evaluation by a neurologist or otolaryngologist.
Discussion
Idiopathic nerve paralysis is a common malady. It affects 20 per 100,000
people a year. Although Bell's palsy was described classically as a pure facial
nerve lesion, and physicians have tried to identify the exact level at which the
nerve is compressed, the most common presenting complaints are related to
trigeminal nerve involvement. The mechanism is probably a spotty
demyelination of several nerves at several sites, caused by a viral infection.
Diabetics and pregnant women have increased incidence of Bell's palsy.