The terms "vertigo" and
"dizziness" are non-interchangeable. Vertigo is defined
as "a sensation of irregular or
whirling motion, either of oneself
or of external objects." [1]
Physical signs of dizziness may be
related to vertigo, but usually
result from different causes. In short, all
manifestations of vertigo include
dizziness, but not all dizziness is
vertigo.
The actual sensation of
vertigo has a relationship with many
conditions. True vertigo is usually
related to an inner ear disorder
known as benign positional
paroxysmal vertigo (BPPV). While the
cause of this peripheral condition
is largely unknown, it is thought to
result from the dislodgement of
normal crystalline structures
located in the part of the ear
involved with sensing balance. For
some, it can follow an upper
respiratory infection or mild head
injury. Attacks last for 30-60
seconds and can be triggered when
rolling over in bed or reaching for
something. It can have
associated hearing loss and ringing
in the ears. BPPV may occur in an episodic
nature as well, with attacks
occurring over the period of a few
days and sometimes weeks. Solitary attacks may
also occur without any precipitating
factors.
It has also been
theorized that Vertigo is caused
by a condition known as Meniere's
disease. Meniere's is another condition
of the ear. This condition is
marked by a pronounced swelling in
the inner ear, and has been associated
to attacks of
vertigo. Meniere's disease has an
elusive cause. It may be related to
viral infections, injury, or
specific allergens.
Central neurologic
disorders, involving connections
between the brain stem and
cerebellum, tend to cause more
long-term bouts of vertigo but are
usually less intense than peripheral
disorders. There is no associated
hearing loss, but there could be
other concomitant symptoms, such as the
uncontrolled jerking of the eyes
back and forth (nystagmus).
Conditions such as multiple
sclerosis, epilepsy, brain
tumors, and neck injury, could cause
associated vertigo due to their
involvement in the central nervous
system.
Cervical vertigo may
be caused by damage to the nerves in
the neck. When these nerves are
damaged, the brain is challenged in
keeping track of the relative
position of the neck and trunk. Whiplash injuries, blunt injuries to
the top of the head, or severe
arthritis in the neck may cause
cervical vertigo. [2]
The brain depends on feedback
from all parts of the body
(especially for positioning) in order to
maintain balance. When this feedback
is skewed, such as in the case of
injury to the nerve plexi of the
neck, the brain has difficulty
interpreting where the body is in
space. This often results in the sensation of
vertigo.
Drugs, including
sedatives, anticonvulsants,
antipsychotics, excessive use of
alcohol, bacterial or viral
conditions in the inner ear (labyrinthitis),
Paget's disease, and some tumors can
all cause vertigo. These
causes should be kept in mind when
investigating the reasons for the
onset of vertigo symptoms. In fact,
vertigo is not necessarily a disease
process in of itself. It is most
often thought of as a symptom of some
other process that is occurring. With this in mind, it is important
for one to obtain an accurate
diagnosis prior to beginning treatment.
Diagnosis of vertigo
is based on specific questioning, diagnostic physical exams, and
possibly, imaging. The eyes are
often checked for abnormal movements, such
as nystagmus. Abnormal eye movements
suggest that a disorder is affecting the
inner ear or nerve connections in
the brain stem. In order to help
make a diagnosis, doctors
will, at times, induce nystagmus by
infecting cold
water directly into the ear. The
direction in which the eyes move
gives an indication of where the
complication may lie. If cervical vertigo
is suspected, persons are given special
glasses to wear and are then
seated in a swivel chair. Depending on their
experience of vertigo while moving
in the chair and/or severity of nystagmus, the doctor can
then make an official
diagnosis for cervical vertigo.
Computed tomography
(CT) can show fractures, infections, and tumors,
which may help to shed light
on the possible causes vertigo. Magnetic resonance imaging (MRI) can
reveal issues involving the brain
stem and cranial nerves as well. If
multiple sclerosis or a brain
infection is suspected, a spinal tap
(lumbar puncture) may be performed
to obtain a sample of cerebrospinal
fluid from the spine. If doctors
suspect that the blood supply to the
brain is decreased, angiography,
doppler ultrasonography, or magnetic
resonance angiography (MRA) of the
head, may be performed to narrow the
diagnosis. [3]
As stated above,
vertigo is a sensation of
disorientation in motion of oneself
or other external objects.
However, it can also cause
additional signs and
symptoms, including;
-
Doctors in the
Untied States reported 5,417,000
patient visits in 1991 because of
dizziness or vertigo. [4]
-
About 545,000
people in the U.S. have Meniere's
disease, with 38,250 being newly
diagnosed each year. [5]
-
The number of
people affected by BPPV each year
has been estimated to be between
10 and 64 per 100,000 people.
However, some experts believe that
even more people may be affected.[6]
-
In the general U.S.
population, which speaks to all
ages, 347,000 hospital days per
year in the United States are
incurred because of "vertiginous
syndromes;"
-
202,000 because of
labyrinthitis (otitis
interna),
-
184,000 because of 'labyrinthitis
unspecified,"
-
And several
thousands more accounted for by
other balance and dizziness
related disorders. [7]
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