BELL’S PALSY/ FACIAL PARALYISIS
Idiopathic, unilateral weakness or paralysis of the facial muscles is referred to as Bell’s palsy. This disorder occurs when an inflammatory neuritis secondary to a viral infection affects the lower motor neurons of cranial nerve VII. Symptoms usually begin to resolve after one week. The majority of affected patients can expect complete recovery. Bell’s palsy is usually not a recurrent phenomenon. In patients who suffer more than one relapse, consider an alternative diagnosis.
Patients often present complaining of an acute onset of unilateral facial paralysis and an inability to close the ipsilateral eye lid. Associated symptoms may include pain behind the ipsilateral ear or along the jaw line and excessive tearing or an inability to produce tears. Loss of taste, gustatory lacrimation (crocodile tears), and hyperacusis may also occur but do so less frequently. Localization of the site of damage of cranial nerve VII is inferred by the symptoms. If the patient suffers paralysis of the musculature of both the upper and lower face, then the lesion is at or distal to the styloid mastoid foramen. If there is associated impairment in taste of the anterior portion on the ipsilateral side of the tongue, then the damage is proximal to the branch of the chordi-tympani. If there is associated hyperacusis, then the site of the lesion is in the internal auditory meatus. If symptoms are bilateral an alternative diagnosis should be considered. If there is an inability to form tears upon stimulation (performed by placing a paper strip in the lower conjunctival sac) then the lesion is at or above the geniculate ganglion. If there is severe periauricular pain associated with vesicular lesions and unilateral facial paralysis, consider the Ramsey Hunt syndrome secondary to herpes zoster (reactivation of varicella zoster virus infection). Facial nerve paralysis may also be associated with HIV infection.
The diagnosis is made clinically based on the characteristic findings after considering other possible causes. Since Bell’s palsy is the most common cause of facial paralysis, no further work up is required. In cases where an alternative diagnosis is suspected, the work up may include antibody levels to Borrelia burgdorferi (Lyme disease), HIV testing, syphilis serologies, and MRI examination (rule out granulomatous infiltration or tumors).
Treatment is controversial. Some physicians believe no therapy is needed other than supportive treatment to include saline eye drops and taping the eye lid shut during sleep to prevent corneal drying. Others advocate the use of corticosteroids (40-80 mg daily X 4 days then tapering over the next 6-8 days). Corticosteroids may be given alone or in combination with an agent effective against herpes virus (acyclovir, valciclovir, or famvir). As stated above, if symptoms are bilateral or recurrent consider another diagnosis.