Hypertension


Albert P. Rocchini, M.D.
Professor of Pediatrics
University of Michigan

What is hypertension?

An elevated blood pressure level in a child is defined as a blood pressure that
is above the 90th percentile for age and sex. Although the finding of
an elevated blood pressure on physical examination constitutes an abnormal sign,
it does not mean that hypertension (i.e., sustained blood pressure elevation) is
persistent. Most pediatricians recommend that for a child to be diagnosed with hypertension
the blood pressure must be abnormal (above the 95th percentile rank of
age and sex) on at least 3 separate examinations over a 6- to 12-month interval
(see table). The only exception is if at the time of the initial examination the
child has signs and/or symptoms commonly found with severe hypertension (e.g., heart
muscle enlargement, headache, dizziness, seizures, eye and vision damage).

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Table: Levels of Severe Hypertension (95th Percentile) for Boys and Girls

Boys Girls
Age (years) Systolic BP Diastolic BP Systolic BP Diastolic BP
1 105 59 104 58
6 112 73 115 75
12 124 81 125 82
17 130 85 136 88

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What causes hypertension?

Once a child is diagnosed with hypertension, its cause must be determined. The two
major types of hypertension are as follows:

  1. Essential hypertension (i.e., without any identifiable cause) occurs in 50%
    to 60% of children with hypertension. The majority of these children will be obese.
  2. Secondary hypertensionThe common causes of secondary hypertension include
    renal (kidney) disease, cardiovascular (heart and vessel) disease, endocrine (hormone
    or metabolism) disorders, and other miscellaneous conditions.

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How is secondary hypertension diagnosed?

A thorough history and physical examination is essential in evaluating a child with
secondary hypertension

In the history, the following significant points should be addressed:

  • Symptoms suggesting associated disease (e.g., unexplained fever – in kidney infection;
    leg pains with exercise – in coarctation of the aorta [see Coarctation of the Aorta
    article]; weight loss and tremor – in hyperthyroidism; sweating, night terrors,
    and palpations – in an adrenal gland tumor)
  • Medications or chemicals that can raise the blood pressure (e.g., birth control
    pill, steroids, amphetamines)
  • Any history of trauma

The physical examination should include the following:

  • Blood pressure and pulse should be taken in both the upper and the lower extremities.
    (A difference in pressure and pulse between the arms and the legs is diagnostic
    of coarctation of the aorta.)
  • A careful abdominal examination should be performed to detect masses (e.g., polycystic
    kidney disease, where the kidneys are too large because of multiple cysts; tumors)
    and abnormal pulses (e.g., renal artery stenosis, where the vessels supplying blood
    to the kidneys are abnormally narrow).
  • A careful examination of the skin should be performed (e.g., cafe-au-lait spots
    or brownish spots in neurofibromatosis, striae or skin stretch marks, hirsutism
    or male hair growth pattern of Cushing’s syndrome).
  • A thorough eye examination should be performed.

The only routine laboratory tests that should be performed are as follows: urine
dipstick, blood electrolytes, blood urea nitrogen, and creatinine. Other laboratory
tests should be ordered based on both the history and the physical examination.

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How is childhood hypertension treated?

All children with significant, sustained hypertension should be treated. The treatment
of hypertension is divided into two major categories: hypertensive crisis and chronic
hypertension.

  1. Hypertensive crisis is defined as life-threatening hypertension that is associated
    with hypertensive encephalopathy (changes in the brain and neurologic function due
    to the increased blood pressure) and/or acute heart failure. The calcium-channel
    blockers amlodipine and nifedipine are very effective in treating hypertensive crisis.
    Other medications used include diazoxide, nitroprusside, and minoxidil. No matter
    what medication is used, once acute blood pressure reduction is achieved, other
    medicines need to be added to maintain long-term blood pressure control.
  2. Chronic hypertension
    The ideal therapy for chronic hypertension is to treat, if possible, the underlying
    disease that is responsible for the hypertension. If this is not possible, then
    nonpharmacologic (not using medications) and pharmacologic (using medications) intervention
    is needed.
    • Nonpharmacologic treatment Dietary management should be the initial form
      of therapy in all children with hypertension. Weight loss is the treatment of choice
      for the obese adolescent with essential hypertension. Lowering salt intake also
      can be helpful. In addition to dietary management, other nonpharmacologic therapies
      include quitting smoking, not taking oral contraceptive pills and other vasoactive
      drugs, and avoiding heavy alcohol consumption. Daily physical activity should be
      encouraged.
    • Pharmacologic treatment
      In pediatric patients, the first line of antihypertensive medications are angiotensin
      converting enzyme inhibitors and calcium channel blockers. The most common side
      effect of angiotensin converting enzyme inhibitors is a chronic cough. If a chronic
      cough requires the child to stop taking the converting enzyme inhibitor, an alternate
      therapy is angiotensin receptor antagonists. The most common side effects of calcium
      channel blockers are a rapid heart rate and fluid retention.

      Until recently, diuretics and beta-blockers were the most commonly used drugs to
      treat childhood hypertension. However, most pediatricians are now reluctant to use
      them because of evidence suggesting that these agents may adversely affect plasma
      lipids and insulin sensitivity. Beta-blockers also can cause depression and impair
      school performance.

      Other antihypertensive agents used to treat refractory hypertension include centrally-acting
      drugs (e.g., Clonidine, Guanabenz), alpha-blockers, and vasodilators (e.g., hydralazine,
      minoxidil).

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What is the goal of hypertension treatment?

The goal of therapy is to keep the child’s blood pressure below the 90th
percentile for age and sex. Parents must be taught not only to monitor their child’s
blood pressure at home, but also to monitor for signs of medication-induced side
effects.

Successful therapy should not interfere with the child’s academic performance, involvement
in sports, or interest in social activities. Participation in team sports should
be encouraged unless there is clear evidence of heart dysfunction.

Once the child’s blood pressure is under good control, the child should be evaluated
(at least) on an annual basis to assess cardiac status, physical growth and development,
and sexual maturation patterns.

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References

Report of the Second Task Force on Blood Pressure Control in Children. Pediatrics
1987;79(1):1-25.

Sinaiko AR. Pharmacologic management of childhood hypertension. Pediatr Clin North
Am
1993;40(1):195-212.

Falkner B. Management of hypertensive children and adolescents. In: Izzo JL, Black
HR, eds. Hypertension primer: the essentials of high blood pressure. 2nd
ed. American Heart Association, 1999:424.

About the Author

Dr. Rocchini received both his bachelor of science degree in chemical engineering
and his medical degree from the University of Pittsburgh. He completed his pediatric
residency at the University of Minnesota and his pediatric cardiology fellowship
at the Children’s Hospital of Boston. Dr. Rocchini is currently a professor of pediatrics
and serves as director of pediatric cardiology at the University of Michigan. His
research interests include interventional cardiac catheterization and obesity-induced
hypertension.

Copyright 2012 Albert P. Rocchini, M.D., All Rights Reserved