Texas EMS Magazine, Volume 33, Number 6, November/December 2012 Page: 29
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condition, diabetics are also more likely to
be the ones who will not have a complete
resolution of symptoms, and they are more
likely to experience a recurrence of the
disorder.'2 The peak age for Bell's palsy onset
is during the third and fourth decades of life
(between 20 and 40 years of age). A person
with a recent history of the flu, a cold or an
upper respiratory tract infection is also more
likely to develop Bell's palsy; this is consistent
with the theory that Bell's palsy is linked to a
viral infection.' Finally, the disorder is more
likely to manifest in the winter months, which
could be due to the increased diagnosis of
influenza during this same time period. 2
Signs and symptoms
Bilateral paralysis due to Bell's palsy
is very rare. Only 1 percent of Bell's palsy
patients will have bilateral facial paralysis;
also, out of all cases of bilateral facial paralysis
only 23 percent can be attributed to Bell's
palsy."2 The most common presentation
for Bell's palsy is unilateral facial paralysis
affecting the upper and lower portions of the
face. The fact that it affects the forehead,
eyes and mouth are important and will help
with differentiating Bell's palsy from a
cerebrovascular accident (CVA). This occurs
because with Bell's palsy the peripheral facial
nerve is damaged, not the central nerve.
During a CVA the central nerve, the nerve
running from the cortex to the brain stem, is
damaged, resulting in only the lower half of
the face being affected. To simplify matters,
think of the brain being divided into left and
right halves, then divide those halves again
into top left, bottom left, top right and bottom
right. The motor neuron tracts that control
the forehead muscles originate from the brain
stem; they divide and only one branch crosses
over to the other side of the body just prior
to leaving the brain. The tracts that control
the lower half do not divide in this manner.
This means motor control of the forehead is
supplied by tracts coming from both sides
of the brain. Injury in the brain to the central
nerves will manifest as paralysis on the lower
portion of the opposite side of the face; a CVA
in the left hemisphere causes lower facial
paralysis on the contralateral (right) side. If the
injury is to the peripheral nerves, the crossoverand division has already occurred and the
nerves serving that side of the face will be
affected no matter which side of the brainstem
they originated from. This is what happens
with Bell's palsy, and it explains why the
paralysis occurs on the same side as the lesion
or injury and involves the entire side of the
face (forehead included). This nerve structure
also explains why a patient suffering from a
CVA will typically not have trouble closing
both eyes and furrowing the brow-the nerve
damage affects only the lower half.
Another differentiating factor is that Bell's
palsy is a condition only of the VII nerve-no
other area of the body should be affected.
Gait, grip strength, pronator drift and other
tests used to determine weakness should be
normal for that patient. The patient history will
include an acute onset of the paralysis. Facial
drooping should be evident and patients may
complain of pain. The muscles controlling
the mouth will be affected; this may lead to
drooling and a loss of taste. Since the facial
paralysis includes the muscles surrounding
the eye, patients will often not be able to close
their eyes. This leads to dryness, irritation and
possible corneal abrasions. However, fluid
may be coming from the eye because patients
are unable to blink and hold back the normal
fluid. Besides the acute onset of unilateral
facial paralysis, patients with Bell's palsy may
complain of pain behind the ear on the affected
side.'
Diagnosis
Bell's palsy is a diagnosis of exclusion; all
other possible causes of facial paralysis must
be ruled out. These include Lyme disease,
Guillain-Barre syndrome, Ramsay Hunt
syndrome, meningitis and sarcoidosis. Ramsay
Hunt syndrome is caused by an infection of
the cranial nerves by the varicella zoster virus.
Symptoms include a painful rash around the
ears. A thorough patient history and assessment
will help rule out many of these other
possibilities and should include discussion of
recent exposure to ticks, rash, fever, history of
viral infection and the presence of ear pain.
Treatment
Bell's palsy is usually a transient condition
that begins suddenly and whose symptomsNovember/December 2012 Texas EMS Magazine 29
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Texas. Department of State Health Services. Texas EMS Magazine, Volume 33, Number 6, November/December 2012, periodical, November 2012; Austin, Texas. (https://texashistory.unt.edu/ark:/67531/metapth541925/m1/29/: accessed July 18, 2024), University of North Texas Libraries, The Portal to Texas History, https://texashistory.unt.edu; crediting UNT Libraries Government Documents Department.