Hypertension
Table: Levels of Severe Hypertension (95th Percentile) for Boys and Girls
How is secondary hypertension diagnosed?
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).
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 |
What causes hypertension?
Once a child is diagnosed with hypertension, its cause must be determined. The two major types of hypertension are as follows:
- 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.
- 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.
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.
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.
- 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.
- 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).
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.
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