Diagnosis
When evaluating a patient with facial paresis/paralysis for Bell's palsy, the
following should be considered:
Î Bell's palsy is rapid in onset (<72 hours).
Î Bell's palsy is diagnosed when no other medical etiology is identified as a
cause of the facial paresis/paralysis.
Î Bilateral Bell's palsy is rare.
Î Currently, no cause for Bell's palsy has been identified.
Î Other conditions may cause facial paresis/paralysis, including stroke, brain
tumors, tumors of the parotid gland or infratemporal fossa, cancer involving
the facial nerve, and systemic and infectious diseases, including varicella
zoster, sarcoidosis, and Lyme disease.
Î Bell's palsy is typically self-limited. Most patients with Bell's palsy
show some recovery without intervention within 2-3 weeks after onset of
symptoms and completely recover within 3-4 months.
Î Bell's palsy may occur in men, women, and children but is more common
in persons 15-45 years old; individuals with diabetes, upper respiratory
ailments, or compromised immune systems; and during pregnancy.
Table 1. Abbreviations and Definitions of Common Terms
Term Definition
Acute Occurring in <72 h
Bell's palsy Acute unilateral facial nerve paresis/paralysis with onset in <72
h and without identifiable cause
EMG testing A test in which a needle electrode is inserted into affected
muscles to record both spontaneous depolarizations and the
responses to voluntary muscle contraction
ENoG testing
(neurophysiologic studies)
A test used to examine the integrity of the facial nerve, in which
surface electrodes record the electrical depolarization of facial
muscles following electrical stimulation of the facial nerve
Facial paralysis Inability to move the facial muscles
Facial paresis Impaired ability to move the facial muscles
