High
Blood Pressure in Children and Adolescents
Blood
pressure, measured with a blood pressure cuff
and stethoscope by a nurse or other healthcare
provider, is the force of the blood pushing against
the artery walls.
Two
numbers are recorded when measuring blood pressure:
- The higher number,
or systolic pressure, refers to the pressure
inside the artery when the heart contracts and
pumps blood through the body.
- The lower number, or
diastolic pressure, refers to the pressure inside
the artery when the heart is at rest and is
filling with blood.
Each
time the heart beats, it pumps blood into the
arteries, resulting in the highest blood pressure
as the heart contracts.
Both
the systolic and diastolic pressures are recorded
as "mm Hg" (millimeters of mercury). This recording
represents how high the mercury column is raised
by the pressure of the blood.
High
blood pressure means that there is higher than
normal pressure inside the arteries either during
systole (when the heart contracts and pumps blood
through the body), or during diastole (when the
heart is at rest and is filling with blood).
- If the pressure is
high during the pumping phase (systole), then
the first number recorded with a blood pressure
reading (the systolic pressure) will be high.
- If the pressure is
high during the resting period (diastole), then
the second number recorded (the diastolic pressure)
will be high.
High
blood pressure is also called hypertension.
Blood
pressure can be affected by many factors, including
the following:
- the time of day
Blood pressures fluctuate during waking hours,
and are lower as we sleep.
- physical activity
Blood pressure is usually higher during and
immediately after exercise, and lower at rest.
- emotional moods
Feelings (such as fear, anger, or happiness)
can affect blood pressure.
- stress
Physical or emotional stress can elevate blood
pressure.
- your child's age,
height, weight, and gender
Blood pressure varies for each child.
- other illnesses
Other illnesses your child may have (such as
kidney or heart disease) affects blood pressure.
Children
(and adults) may be anxious in a physician's office,
not knowing what may happen and being afraid of
a possibly painful experience ahead of them. Infants,
toddlers, and preschoolers may be fearful of being
separated from their parent or caregiver. Many
emotions related to visiting the clinic can affect
blood pressure and may give falsely high readings.
Before
determining that a child has high blood pressure,
a physician or nurse will take several readings
when your child is calm, and you are present to
comfort him/her, if needed. The staff may let
some time elapse before retaking a blood pressure
reading, to make sure your child has rested and
become calm. More meaningful blood pressure readings
can be obtained this way.
Blood
pressures vary depending on the age of your child,
as well as according to height and weight, and
the gender of your child. Generally, blood pressure
is low in infancy, and rises slowly as children
age. Boys' blood pressures are slightly higher
than girls' are, and taller people generally have
higher blood pressures than short people do.
For
example, an infant may have a quite normal blood
pressure of 80/45 mm Hg, while that value in an
adult is considered low. A teenager may have an
acceptable blood pressure of 110/70 mm Hg, but
that value would be of concern in a toddler.
The
National High Blood Pressure Education Program
(NHBEP) recently prepared tables that help a physician
determine when your child's blood pressure is
higher than other children's blood pressure. The
NHBEP prepared a table for boys and a separate
one for girls. A range of blood pressure values
is given based on how old and how tall your child
is. According to the tables, If your child has
a blood pressure that is higher than 90 to 95
percent of other boys or girls his/her age and
height, then he or she may have high blood pressure.
Again,
many factors, including emotions, can affect blood
pressure. Readings that are high compared to the
values on the table may need to be investigated
further by your child's physician.
High
blood pressure, or hypertension, directly increases
the risk of coronary heart disease (heart attack)
and stroke (brain attack). With high blood pressure,
the arteries may have an increased resistance
against the flow of blood, causing the heart to
pump harder to circulate the blood.
Heart
attack and stroke related to high blood pressure
are rare in children and adolescents. Yet, studies
of young adults with high blood pressure found
that many had high blood pressure as a child.
By their 20s, studies show that children and adolescents
with high blood pressure will exhibit harmful
effects on the heart and blood vessels even with
mild hypertension.
Blood
pressure is classified as "primary," or without
a definite cause, and "secondary," or related
to an illness or behavior.
Factors
that seem to contribute to primary hypertension
in adults, and possibly in children, include the
following:
- high blood cholesterol
levels
- being overweight
- inactivity
- smoking
Secondary
causes of hypertension in children include the
following:
- illnesses
The kidneys play an important role in regulating
blood pressure, and often have diminished ability
to perform this vital task when they are diseased.
A congenital (present at birth) heart defect
called coarctation of the aorta may also cause
high blood pressure readings. Head injury may
raise the pressure inside the brain, which affects
the body's ability to regulate blood pressure
normally.
- use of prescription
or illegal recreational drugs (such as steroids
taken to decrease inflammation, oral contraceptives,
or cocaine)
- obesity
- immobility (such as
with a chronic illness)
- severe pain (such as
with cancer or burns)
- Primary hypertension
(with an unknown cause) is the most common cause
of high blood pressure in adolescents and adults,
but is less common in children.
- Many children with
high blood pressure also have adult relatives
with hypertension, so there may be a hereditary
aspect to the disease.
- There is a higher incidence
of high blood pressure in African-American children
after the age of 12 and into adulthood.
Your
child's physician may note an elevated blood pressure
reading during a routine office visit. Obtaining
calm, resting blood pressures on several different
occasions (days, weeks, or months apart) will
provide better information about whether the blood
pressure elevation is consistent or due to fear
or stress.
Your
child's physician will obtain a medical history,
including information about your child's diet,
exercise level, home and school activities, and
possible stressors. A physical examination may
also be performed.
Diagnostic
tests may help determine if your child's high
blood pressure is related to an illness, or is
"essential" or "primary" hypertension, meaning
it has no known cause. Diagnostic procedures may
include:
- urinalysis
- blood tests (including
those to evaluate kidney function and cholesterol
levels)
Other
tests may be needed to evaluate the health of
other organs (such as the heart or kidneys) which
may contribute to hypertension.
Specific
treatment for high blood pressure will be determined
by your child's physician based on:
- your child's age, overall
health, and medical history
- extent of the condition
- your child's tolerance
for specific medications, procedures, or therapies
- expectations for the
course of the condition
- your opinion or preference
If a
secondary cause has been found, such as kidney
disease, the underlying disease will be treated.
If no cause has been determined, the first treatment
approach is lifestyle therapy, including the following:
- weight reduction
- increasing physical
activity
- healthy diet
These
interventions can lower systolic and diastolic
blood pressure, improve the strength of the heart,
and lower blood cholesterol - all important steps
in preventing heart disease as an adult.
Medications
to control high blood pressure are only needed
in about 1 percent of children with the disorder.
Consult your child's physician for more information.
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