PEDIATRIC HYPERTENSION

John K. Stevens, Jr. M.D., F.A.C.C.

The Fourth Report on the Diagnosis, Evaluation and Treatment of High Blood Pressure in Children and Adolescents¹ appears at a time when there is increased public awareness of hypertension, as well as obesity, type II diabetes mellitus, dyslipidemia and physical inactivity as prevalent and serious cardiovascular risk factors in the young. The Report should be used as a guide for both the primary care provider and specialist.

What are the major messages from the Report for the primary care setting?

1. Measure the blood pressure: in all children greater than 3 years of age by auscultation and in children less than 3 years of age with a history of prematurity, neonatal intensive care, recurrent urinary tract infections and treatment with drugs known to raise blood pressure, to name a few.
   
   
2. Chart or plot the blood pressure using the new data for gender, age and height percentile: American population data from the 1999-2000 National Health and Nutrition Survey (NHANES)² provides modern tables to classify severity of hypertension.
   
   
3. Review the blood pressure percentile and classify the measurement: A revised population definition consistent with the adult hypertension terminology (JNC7) has been endorsed. (The blood pressure must be obtained on three separate occasions. If the systolic and diastolic blood pressure falls into different categories, classify by the higher category.)
   a. NORMAL BLOOD PRESSURE is defined as a systolic and diastolic blood pressure below the 90th percentile for gender, age and height percentile (utilizing the Center for Disease Control (CDC) growth curves).
   b. PREHYPERTENSION is defined as the 90th percentile to less than 95th percentile or if BP greater than 120/80 even if below the 90th percentile (up to below the 95th percentile).
   c. STAGE 1 HYPERTENSION is defined as a blood pressure between the 95th percentile and the 99th percentile plus 5mmHg.
   d. STAGE 2 HYPERTENSION is defined as a blood pressure above the 99th percentile plus 5mmHg.
   e. “WHITE COAT” HYPERTENSION is defined in a patient with blood pressure above the 95th percentile in the physician’s office or clinic, who is normotensive outside the clinical setting.
   
   
4. Use treatment guidelines to tailor care and referral: A specific set of measurement frequency guidelines, as well as interventions and recommendations for referral are based on the below classifications of hypertension.
   
   
5. Identify primary (essential) hypertension and comorbidities: Primary hypertension is identified as a significant health problem, with overweight/obesity being a major contributor to much of the prehypertension and stage¹ hypertension. Body mass index (BMI) should be calculated and plotted on the CDC growth curves in pediatric patients. The prevalence of hypertension increases with increased BMI; hypertension is present in about 30 percent of those with BMI above the 95th percentile.
   
   Classification of Hypertension in Children and Adolescents, With Measurement Frequency and Therapy Recommendations

	SBP or DBP Percentile*	Frequency of BP Measurement	Therapeutic Lifestyle Changes	Pharmacologic Therapy
Normal	<90th	Recheck at next scheduled physical examination	Encourage healthy diet, sleep and physical activity	___
Pre- hypertension	90th to <95th or if BP exceeds 120/80 even if <90th percentile up to <95th percentile†	Recheck in 6 mo	Weight-management counseling if overweight; introduce physical activity and diet management‡	None unless compelling indications such as chronic kidney disease, diabetes mellitus, heart failure or LVH exist
Stage 1 hypertension	95th–99th percentile plus 5 mm Hg	Recheck in 1–2 wk or sooner if the patient is symptomatic; if persistently elevated on 2 additional occasions, evaluate or refer to source of care within 1 mo	Weight-management counseling if overweight; introduce physical activity and diet management‡	Initiate therapy based on indications or if compelling indications exist
Stage 2 hypertension	>99th percentile plus 5 mm Hg	Evaluate or refer to source of care within 1 wk or immediately if the patient is symptomatic	Weight-management counseling if overweight; introduce physical activity and diet management‡	Initiate therapy§

* For gender, age and height measured on at least 3 separate occasions; if systolic and diastolic categories are different, categorize by the higher value.

† This occurs typically at 12 years old for SBP and at 16 years old for DBP.

‡ Parents and children trying to modify the eating plan to the Dietary Approaches to Stop Hypertension Study eating plan could benefit from consultation with a registered or licensed nutritionist to get them started.

§ More than 1 drug may be required.

Reproduced by permission of Pediatrics, Vol. 144 (2), page 560. Copyright 2004.


The Report emphasizes the need to assess for additional cardiovascular risk factors, including dyslipidemia, hyperinsulinemia/diabetes mellitus, a diet high in saturated fats/calories/sodium, smoking, lack of moderate to vigorous physical activity several times per week and increased sedentary time, as well as family history of hypertension, atherosclerosis and diabetes. There is an emphasis on diagnosis and management of the metabolic syndrome (insulin resistance syndrome), an association of hyperinsulinemia, truncal obesity, dyslipidemia (especially hypertriglyceridemia and low high density lipoprotein), hypertension and occasionally glucose intolerance. The metabolic syndrome may be present in 30 percent of pediatric patients with a BMI above the 95th percentile.

Therefore, a fasting lipid profile is recommended in all overweight patients with prehypertension and in all hypertensive patients, as well as those with a family history of dyslipidemia, hypertension or atherosclerosis. A fasting insulin and glucose should be obtained in the overweight hypertensive. (Additional testing for diabetes, such as a hemoglobin A1c and/or oral glucose tolerance test may be indicated.) Since obstructive sleep apnea is associated with overweight and systemic hypertension, appropriate history taking, physical exam and diagnostic studies should be carried out if appropriate. Additional lab evaluation should be directed by history, physical exam findings, severity of hypertension and comorbidities.

A reasonable evaluation for suspected primary hypertension includes a urinalysis (with microscopic), serum electrolytes, BUN, creatinine and direct renin. A renal ultrasound with renal artery/vein Doppler and resistive indices or renal scan should be done unless the hypertension is clearly primary or obesity related. All hypertensive patients should have an echocardiogram to assess for left ventricular hypertrophy. Some resources for care include: the Children’s Sibley Preventive Cardiology Clinic at 404-256-2593 or 800-542-2233, the American Heart Association (www.americanheart.org), the Children’s Clinical Nutrition Department and also the American Dietetics Association (www.eatright.org).

1. Rule out secondary causes of hypertension: The Report concisely summarizes physical findings that suggest certain secondary causes and also outlines diagnostic studies, in two tables. These tables should be reviewed when confronted with a patient with possible secondary hypertension. Several general points may be helpful in this situation.
   a. The younger the patient and the higher the blood pressure the more likely there will be a secondary cause. Very young children, children with stage 2 hypertension, and children or adolescents with clinical signs that suggest systemic conditions associated with hypertension should be evaluated more completely than in those with stage 1 hypertension.
   b. The majority of secondary hypertension (70 percent to 80 percent) is renal parenchymal in origin.
   c. Cardiovascular (coarctation of the aorta) and renovascular causes are second in frequency.
   d. Endocrine (except the metabolic syndrome) and neurologic causes are uncommon.
   e. Pharmacologic causes (prescription/nonprescription/supplements/abuse) of hypertension should be considered.
   f. Rule out reasonable secondary causes of hypertension prior to making a diagnosis of primary hypertension.
   g. Blood pressures should be measured in both arms and a leg.
   h. The list of secondary causes is long, such that sufficient and efficient evaluation may require the help of one or more hypertension specialists, such as a cardiologist or a nephrologist.
   i. It is important to remember the most common causes of hypertension by age group:
   NEWBORN INFANTS: renal artery thrombosis, renal artery stenosis, congenital renal abnormality, coarctation of the aorta
   INFANCY TO 6 YEARS: renal parenchymal and structural renal disease, coarctation of the aorta, renal artery stenosis
   6 TO 10 YEARS: renal parenchymal disease, renal artery stenosis, primary hypertension
   ADOLESCENCE: primary hypertension, renal parenchymal disease
   
   
2. Recognize and screen for target organ abnormalities in childhood hypertension: Target organ abnormalities are commonly associated with hypertension in children and adolescents. LVH is the most prominent (and easily measured) evidence of target-organ damage. The Report recommends that pediatric patients with established hypertension should have echocardiographic assessment of left ventricular mass at diagnosis and periodically thereafter. The presence of LVH is an indication to initiate or intensify antihypertensive therapy.
   
   
3. Institute therapeutic lifestyle changes: The Report emphasizes these first-line treatments for prehypertension and hypertension and recognizes their importance even with pharmacologic therapy. Weight reduction is the primary therapy for obesity-related hypertension. Prevention of excess or abnormal weight gain may limit future increases in blood pressure. Evidence is given for the benefits of regular physical activity and restriction of sedentary activities, as well as dietary modifications in weight management and hypertension. These therapies should be applied not only to the prehypertensive patient, but should be continued in the hypertensive even if requiring pharmacologic intervention. Emphasis on therapy should shift away from an aesthetic goal of weight loss to a health goal of normotension (or improved lipid profile or decreased insulin) and should be family-based, stepwise and achievable. Steps that can be implemented in the primary care setting include:
   
   a. The patient should be encouraged to self-monitor time spent in sedentary activities (TV, computer, video games) and decrease these activities to less than 2 hour per day.
   b. The family and patient should identify physical activities that the child enjoys, engage in them regularly and self-monitor time spent in moderately vigorous physical activities (minimal 30 to 60 minutes per day; though more time is probably more historically normal). A pedometer (cost about $20) can serve as a useful monitoring device for the patient that gives quantitative feedback on physical activity. Make a goal of more than 10,000 steps per day. This will require physical activity beyond the usual day at school and light play.
   c. Dietary changes can involve portion-size control, decrease in consumption of sugar-containing beverages and energy dense snacks, increase in consumption of fresh fruits and vegetables, and regular meals. Composition changes include limiting sodium, total fat and saturated fat, while increasing foods with potassium, magnesium, folate, fiber, unsaturated fat and possibly calcium.
   d. Consultation with a nutritionist.
   e. Monitor compliance and goals at follow-up and provide support and positive feedback.
   f. Referral if not achieving goals.
   g. Encourage (rather than limit) sports and workouts in all but uncontrolled stage 2 hypertensive patients or when a significant secondary cause is present. Aerobic activities and repetitive resistance training (weights) have both been shown to lower blood pressure. Limit only power weight lifting (lifting a weight that can only be done about one to four times in rapid succession) in the hypertensive.
   
   
4. When necessary institute pharmacologic therapy: The Report provides an extensive list of antihypertensive drugs for outpatient management and a list of drugs for severe hypertension to be used in the acute care setting. The principles of pharmacologic therapy are:
   
   a. The indications for antihypertensive drug therapy in children includes secondary hypertension and insufficient response to lifestyle modification.
   b. Pharmacologic therapy, when indicated, should be initiated with a single drug.
   c. Acceptable classes for use in children include ACE inhibitors, angiotensin receptor blockers, beta-blockers, calcium channel blockers and diuretics.
   d. The goal for antihypertensive treatment in children should be reduction of BP to below the 95th percentile unless concurrent conditions are present, in which case BP should be lowered to below the 90th percentile.
   e. Severe, symptomatic hypertension should be treated with intravenous antihypertensive drugs.
   f. Become familiar with a proven, effective drug in each class. For instance, I usually use lisinopril (ACE inhibitor), amlodipine (calcium channel blocker) and hydrochlorothiazide (thiazide diuretic). Know the side effects that may cause health issues or lack of compliance. I generally avoid beta-blockers in patients where physical activity is important (athletes and/or overweight).
   g. Use combination agents (at lower dose) over significant increases in dose of a single agent to minimize side effects.
   h. With improved lifestyle modifications and/or weight loss, consider a trial off medications with close monitoring.
   
   Keep the Report available for reference and preprint the blood pressure tables for use in the clinic. Start with a clinical evaluation
   and treatment.
   
   Consultative services for childhood and adolescent hypertension, as well as dyslipidemias, are available at the Pediatric Preventive Cardiology Clinic of Sibley Heart Center Cardiology. Telephone consultations are also available. Please call 404-256-2593 or 800-542-2233.

References

1. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics 2004; 114:555-576.
   
2. 1999-2000 National Health and Nutrition Examination Survey (NHANES)
   
3. Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 Report. JAMA 2003; 289: 2560-2572(PR).

John K. (“Jack”) Stevens Jr., M.D., F.A.C.C.

John K. (“Jack”) Stevens Jr., M.D., F.A.C.C. is Director of Preventive Cardiology at Sibley Heart Center Cardiology, Chief of Cardiology at Children’s Healthcare of Atlanta at Scottish Rite and Assistant Professor of Pediatrics at Emory University. Dr. Stevens is a graduate of Washington University School of Medicine (1985). His training includes a pediatric residency (1988) and chief residency (1989) at St. Louis Children’s Hospital, a cardiology fellowship (1992) and an NIH postdoctoral fellowship (1993) in exercise physiology at the Section of Applied Physiology and preventive cardiology at the Lipid Research Center, all at Washington University. He joined the Children’s Sibley Heart Center in 1993. Areas of special interest in addition to preventive cardiology include exercise physiology and cardiac intensive care.

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