Syncope
Syncope
is a temporary loss of consciousness and muscle
tone caused by inadequate blood supply to the
brain. Syncope is better known as fainting.
Syncope
accounts for 3 percent of emergency room visits
and 6 percent of hospital admissions, according
to the American Heart Association.
The
common reason behind each syncopal or fainting
episode is a temporary lack of oxygen-rich (red)
blood getting to the brain. However, many different
problems can cause a decrease in blood flow to
the brain. Types of syncope include:
- vasovagal syncope
The most common type of syncope is called vasovagal
syncope. A variety of situations stimulate the
vagus nerve, which leads to a slowing of the
heart rate and dilation of the body's blood
vessels. With a slow heart rate and dilated
blood vessels, less blood gets to the brain,
and fainting occurs. Pain and emotional stress
can trigger vasovagal syncope in susceptible
people. This type of syncope can happen more
often in some families.
- orthostatic hypotension
Another cause of syncope is orthostatic hypotension.
This is a drop in blood pressure that occurs
when a person has been standing for a while,
or changes from a sitting to a standing position.
Blood tends to pool in the legs, keeping a normal
amount of blood from being returned to the heart,
and thereby preventing a normal amount of blood
from leaving the heart and going to the body.
A momentary drop in blood flow to the brain
occurs, and a person faints.
Some
children have abnormalities of the structures
of the heart that can cause syncopal episodes.
Heart defects causing "outflow obstruction" may
produce fainting because they restrict the blood
flow to the body out of the left ventricle. Aortic
stenosis and hypertrophic cardiomyopathy diminish
the blood flow from the left ventricle through
the aorta, and children with these problems may
experience syncope.
Irregular
or rapid heart rhythms can also trigger syncope.
When the heart beats rapidly or irregularly, the
ventricles have less time to fill with blood before
it is time to pump whatever blood is within them
to the lungs or to the body. Not as much blood
as normal leaves the heart and flows through the
aorta with these abnormal rhythms, and the body
reacts to the diminished blood flow to the brain
by fainting.
Yet
another cause of syncope can be an inflammation
of the heart muscle known as myocarditis. The
heart muscle becomes weakened and is not able
to pump as well as normal. The body again reacts
to decreased blood flow to the brain by fainting.
Other
situations or illnesses that can cause syncope
include, but are not limited to, the following:
- head injury
- epilepsy
- stroke
- inner ear problems
- dehydration
- low blood sugar
- breath holding episodes
The
following are the most common symptoms of syncope.
However, each child may experience symptoms differently.
Also, the symptoms of syncope may resemble other
conditions or medical problems. Consult your child's
physician for a diagnosis.
Some
children will experience presyncope, which is
the feeling that they are about to faint. Your
child may be able to tell you that he/she is "about
to pass out," "feels like I might faint," "feels
like the room is spinning," or "feels dizzy."
These sensations usually occur immediately before
fainting occurs. There may be enough warning to
enable your child to sit or lie down before loss
of consciousness occurs; this can prevent injuries
that may occur due to falling during syncope.
In other
instances, the child will have no presyncopal
sensations, but will simply faint.
Some
types of syncope are caused by a serious problem,
so it is recommended that your child be seen by
a physician to determine the reason of all fainting
spells.
Your
child's physician will obtain a medical history
and perform a physical examination. The details
about the syncopal episodes are helpful in pinpointing
the cause: how often they occur, what activity
your child was participating in prior to fainting,
if there were any presyncopal sensations, and
other symptoms provide useful information. Blood
pressure may be taken in sitting and standing
positions to check for orthostatic hypotension.
Other
diagnostic tests may include:
- blood tests (to evaluate
causes such as low blood sugar and dehydration)
- electrocardiogram (ECG
or EKG) - a test that records the electrical
activity of the heart, and shows abnormal rhythms
(arrhythmias or dysrhythmias).
- tilt table test
- Holter monitor - portable
EKG machine worn for a 24-hour period or longer
to evaluate irregular, fast, or slow heart rhythms
while engaging in normal activities.
- echocardiogram (echo)
- a procedure that studies or evaluates the
heart's function by using sound waves produce
a moving picture of the heart and heart valves.
Specific
treatment for syncope will be determined by your
child's physician based on:
- your child's age, overall
health, and medical history
- extent of the condition
- cause of the condition
- your child's tolerance
for specific medications, procedures, or therapies
- expectations for the
course of the condition
- your opinion or preference
For
vasovagal syncope, avoiding the situations that
trigger the episodes is recommended.
For
illnesses causing syncope, such as irregular heart
rhythms or epilepsy, medications may be prescribed
by your child's physician to help control the
disease.
With
outflow obstructions, surgical repair of the heart
problem may be indicated. Consult your child's
physician regarding specific information for your
child.
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