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Overview
Vertigo and dizziness are symptoms
that individuals may experience, and not diseases
in themselves. Many different underlying problems
may cause the sensation of dizziness or vertigo.
Vertigo refers to the subjective
sensation of movement. There is often, but not
always some sensation of spinning that may occur.
Many people feel either that they, or the
environment may be moving around them. Others feel
that they are being pulled or are in some state of
imbalance. Dizziness is usually the term that
people use to describe the feeling that they may
feel inside. It often refers to a wider range of
symptoms including lightheadedness, imbalance,
disorientation and fainting.
These disorders may signify some
problem with the vestibular system, which is
responsible for integrating all the sensory
stimuli we see, hear and feel with regard to head
and body movement.
Vestibular Anatomy
The vestibular system monitors all the forces and
direction of movement of the head, transmits these
signals to specialized organs inside the ear, and
then relays the information to particular parts of
the brain. Part of this system is said to be
peripheral (middle ear organs ) and the other part
central (the vestibular nerve to the brain). Our
ears are an essential part of this system. In
addition to transmitting soundwaves, which become
interpreted as sounds, transmits the appropriate
vestibular information about movement to the
brain. Inside the inner ear is the labyrinth,
which contains three semicircular canals, which
are surrounded by a special fluid. The
semicircular canals, by means of receptor organs,
which have specialized hair cells on them,
transmit the information about different forms of
head movement, and send it to the vestibular
nerve. This nerve, in turn is responsible for
transmitting this information to the brainstem,
cerebellum (specialized part of the brain that
deals with coordination) and the cerebral cortex.
In addition, our visual system
(eyes and connection to the brain), auditory
system (hearing), and sensory system provide
information about our surroundings that may
influence feelings and perceptions about both
normal and abnormal movement.
Symptoms
Symptoms of dizziness and vertigo
can be very disabling. Many patients experience a
sense of rotary movement, either that the place
that they are in is moving, or a feeling that they
are spinning around and cannot get their bearings.
Some people describe a feeling of being pulled
toward the floor or toward one side of the room.
Often it may be difficult to focus visually, and
many patients find it so uncomfortable to even
keep their eyes open during the spells. Nausea and
vomiting are common. Sweatiness and heart
palpitations may also accompany the events.
Symptoms may or may not be brought
on moving the head or changing the position in
regard to objects around them. Many patients find
it hard to lay in bed and turn their head, as the
symptoms may become almost unbearable.
Some individuals have a more
generalized feeling of lightheadedness without
true spinning or rotation. They describe a
"floating or heavy sensation" in the head.
Diagnosis
One of the more important
components of the evaluation of individuals with
these symptoms is the clinical history and the
neurological examination. It is often helpful for
patient to give their health care providers the
best description possible of the character of the
symptoms. It is important to know what triggers
the dizziness or vertigo, how long it lasts, what
other symptoms accompany the feeling, and what
makes it better or worse. The neurological
examination involves testing the nerves and
muscles of the face (particularly hearing),
testing strength and coordination, balance and
walking. Careful evaluation of heart rate and
blood pressure is also usually performed. A
special test that may provoke the symptoms and
help to determine where in the vestibular system
the problem may be is often called the "Barany
Hallpike" maneuver. The patient is placed on a
table and told to turn the head to either the
right or left side. With the head in this
position, they are placed in the lying position on
their back, with the head gently held below the
table. The clinician looks for symptoms of
dizziness, and the presence of a type of eye
movement known as nystagmus. The movement is then
repeated with the head in the opposite direction.
Imaging Studies
Some patients will undergo imaging studies of the
brain. These can include CAT scan (computerized
tomography) and MRI (magnetic resonance imaging)
of the brain. MRI allows for better visualization
of the brainstem and cerebellum, areas of the
brain that may be abnormal in this setting. Stroke
or brain tumors can be seen with MRI.
Laboratory studies including a
complete blood count (CBC), lever, kidney and
thyroid panels should be performed. If patients
are taking medication, drug levels should be
obtained.
Electronystagmography (ENG)
Electronystagmography (ENG) is a neuro-physiological
test that can test the vestibular system. Patients
undergo a series of tests of both ears, studying
the eye-movements and responses to changes in
posture and head position. This test helps to
evaluate the inner structure of the ear,
particularly the semi-circular canals. Comparing
function in both ears is often useful. Audiometry
tests hearing in both ears and is very helpful
when diseases such as Menieres syndrome or a tumor
involving the angle between the cerebellum and
brain is suspected.
Treatment
In many cases, identifying the
underlying etiology of the dizziness or vertigo
will cure the problem. For example if a particular
drug is responsible, lowering the dose or
discontinuing it may be sufficient. If
abnormalities in a diabetic (such as very low or
very high blood glucose) are discovered,
maintaining a more normal blood sugar may help.
Maintaining adequate hydration (drinking a lot of
fluids ), avoiding alcohol, and not missing meals
is often good advice.
When medication is necessary, often
meclizine (Antivert) is used first. It is an oral
medication, that can be taken either daily for a
period of time, or only when needed. It can be
taken up to 3 times a day, and for some people can
be very helpful. The usual starting dose is 25mg.
The main side effect is drowsiness. If this is not
helpful, clonazepam (Klonopin) can be tried. It
can be taken up to 3 times a day when needed. It
often produces drowsiness. Promethazine (Phenergan)
can be taken either orally or by suppository form.
Side effects involving abnormal movements can
occur.
There are also forms of therapy
that involve having patients go through a series
of head movements to allow the canals and inner
ear structures to adjust to whatever condition is
causing the symptoms. This is often known as
vestibular habituation therapy. There are
specialists who study this type of therapy and
administer it in for patients when its
appropriate. |
