FACIAL PARALYSIS
FACIAL PARALYSIS: Excerpt from Differential Diagnosis in Primary Care
A facial palsy is usually considered to be Bell palsy and it frequently
is. Nevertheless, the clinician who begins treatment without ruling out
other possibilities will eventually get burned. Anatomy is the key to
recalling these possibilities before the patient leaves the office. Follow
the facial nerve from its origin along its pathway to its termination, and
all the causes should come to mind.
Origin. Diseases of the brain and brainstem are considered here.
They are usually distinguished from Bell palsy by the presence of other
neurologic findings. The mnemonic ANITA will help recall them in an
organized fashion.
A—Arterial diseases include aneurysms, emboli, thromboses, and
hemorrhages. Occlusion of the posterior inferior cerebellar artery will
cause a peripheral facial palsy, but it can easily be distinguished from
Bell palsy by the presence of a Horner syndrome, hoarseness, ataxia, and
crossed hemianalgesia.
N—Neoplasms include gliomas and the cerebellopontine angle tumor or
acoustic neuroma.
I—Inflammation suggests neurosyphilis, tuberculosis, brain abscess,
and encephalitis.
T—Trauma helps recall skull fractures and epidural and subdural
hematomas.
A—Autoimmune disease suggests multiple sclerosis, the collagen
diseases, and early Guillain–Barré syndrome.
Pathway. The facial nerve has a long pathway, and along
that path it can be destroyed by the following:
A—Arterial aneurysms
N—Neoplasms such as acoustic neuromas and parotid gland tumors
I—Inflammatory conditions like herpes zoster, petrositis,
mastoiditis, and cholesteatomas
T—Trauma such as basilar skull fractures and otologic surgery
A—Autoimmune disease such as Bell palsy, or uveoparotid fever
Termination. The site of termination of the facial nerve
should suggest myasthenia gravis, muscular dystrophy, and facial
hemiatrophy. These rarely present with an isolated facial palsy.
Approach to the Diagnosis
The clinical picture will frequently help to determine the cause of
facial paralysis. Peripheral facial palsy as occurs in Bell palsy involves
the forehead muscles and there is difficulty in closing the eyelid, whereas
central facial palsy involves the face and lips and there is often
associated hemiplegia or monoplegia. When there is exclusively a peripheral
facial palsy without hearing loss or other neurologic signs, Bell palsy
should be strongly suspected, although diabetes and myasthenia gravis need
to be excluded. A bilateral peripheral nerve palsy should make one consider
Guillain–Barré syndrome; be on the lookout for paralysis of the
extremities as well. Bilateral facial palsy is also seen in myotonic
dystrophy and myasthenia gravis. A “Bell palsy” with hearing loss and an
aural discharge should prompt consideration of mastoiditis and petrositis.
If there is hearing loss without a discharge, the possibility of an acoustic
neuroma or cholesteatoma must be entertained. The association of a central
facial palsy with hemiplegia brings up a host of possibilities including
subdural hematoma, brain abscess, brain tumor, and cerebrovascular accident.
The workup of these conditions is considered on page 222.
If the patient has clinical Bell palsy, one could start a therapy without a
workup, but it is wise to get an x-ray of the skull and mastoids to rule out
mastoiditis and petrositis and a glucose tolerance test to rule out
diabetes. An acetylcholine receptor antibody titer or Tensilon test would
only be ordered if the palsy were intermittent or there were other cranial
nerve signs. If a middle ear infection or acoustic neuroma is suspected, the
patient needs x-ray of the mastoids and petrous bones and a CT scan or MRI
of the brain and auditory canal.
Other Useful Tests
-
CBC (ear infection)
-
Sedimentation rate (ear infection)
-
Venereal disease research laboratory (VDRL) test (neurosyphilis)
-
Cultures of ear discharge (otitis)
-
Audiogram and caloric tests (petrositis, acoustic neuroma)
-
Posterior fossa myelogram (acoustic neuroma)
-
Electromyogram (EMG) (Bell palsy)
-
Lyme disease antibody titer (Lyme disease)
-
Blood lead level (lead neuropathy)
-
Spinal tap (Guillain–Barré syndrome)
Pictures
Book Source Details
- Book Title: Differential Diagnosis in Primary Care
- Author(s): R. Douglas Collins MD, FACP
- Year of Publication: 2007
- Copyright Details: Differential Diagnosis in Primary Care, Copyright © 2007 Lippincott Williams & Wilkins.
More About Tropical Spastic Paraparesis
More Medical Textbooks Online about Tropical Spastic Paraparesis
Review other book chapters online related to Tropical Spastic Paraparesis:
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
» Next page: WEAKNESS OR PARALYSIS OF ONE OR MORE EXTREMITIES (Differential Diagnosis in Primary Care)
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