# Pediatric Hypertension

## Introduction

Pediatric hypertension has gained increasing recognition as a significant and prevalent health concern. The 2017 AAP Clinical Practice Guideline updated the normative blood pressure tables and definitions, resulting in a higher prevalence of identified hypertension in children. Unlike adults, where essential (primary) hypertension predominates, secondary hypertension is more common in younger children, and identifying the underlying cause is critical. Untreated hypertension in childhood leads to target organ damage including left ventricular hypertrophy, retinal changes, and increased cardiovascular risk extending into adulthood.

## Definitions (2017 AAP Guidelines)

### Children Aged 1-13 Years

| Category | Ages 1-13 Years | Ages ≥13 Years |
|----------|----------------|----------------|
| Normal | <90th percentile | <120/80 mmHg |
| Elevated BP | ≥90th to <95th percentile OR 120/80 to <95th %ile | 120-129/<80 mmHg |
| Stage 1 HTN | ≥95th to <95th + 12 mmHg OR 130/80-139/89 | 130-139/80-89 mmHg |
| Stage 2 HTN | ≥95th + 12 mmHg OR ≥140/90 | ≥140/90 mmHg |

For children aged 1 to 13 years, normal blood pressure is defined as below the 90th percentile for age, sex, and height. Elevated BP (previously termed prehypertension) falls at or above the 90th percentile but below the 95th percentile, or between 120/80 mmHg and the 95th percentile, whichever is lower. Stage 1 hypertension is defined as BP at or above the 95th percentile but below the 95th percentile plus 12 mmHg, or 130/80 to 139/89 mmHg, whichever is lower. Stage 2 hypertension is BP at or above the 95th percentile plus 12 mmHg, or at or above 140/90 mmHg, whichever is lower.

### Adolescents 13 Years and Older

For adolescents aged 13 years and older, adult thresholds apply. Normal is below 120/80, elevated is 120-129 systolic with diastolic below 80, Stage 1 is 130-139/80-89, and Stage 2 is 140/90 or greater.

### Key Measurement Principles

Accurate blood pressure measurement requires an appropriately sized cuff, with the bladder width covering 40% of the arm circumference and the length encircling 80-100% of the arm. Measurement should be taken in the right arm (to exclude coarctation of the aorta), with the child seated, feet on the floor, and after 5 minutes of rest. The auscultatory method is the gold standard for confirmation; oscillometric devices are acceptable for screening, but elevated readings must be confirmed by auscultation. Three measurements on three separate occasions are required before diagnosing hypertension, unless the child presents with Stage 2 hypertension and symptoms.

<image>Illustration showing the correct blood pressure measurement technique in a child, including proper cuff sizing (40% arm circumference width, 80-100% length), correct patient positioning (seated, back supported, feet flat on floor, right arm at heart level), and a comparison of an appropriately sized versus too-small cuff with the resulting impact on blood pressure readings</image>

## Etiology

### Primary (Essential) Hypertension

Primary hypertension is increasingly common, particularly in older children and adolescents. It is strongly associated with obesity (BMI at or above the 95th percentile), which is the most important modifiable risk factor, and with a family history of hypertension and cardiovascular disease. Primary hypertension is often mild (Stage 1) and associated with other metabolic risk factors such as dyslipidemia and insulin resistance. It remains a diagnosis of exclusion, and secondary causes should be evaluated, especially in younger or more severely hypertensive children.

### Secondary Hypertension

Secondary hypertension is more common in younger children (under 6 years) and in those with Stage 2 hypertension. Renal parenchymal disease is the most common secondary cause and includes glomerulonephritis, reflux nephropathy, polycystic kidney disease, chronic kidney disease, and hemolytic uremic syndrome. Renovascular disease, particularly renal artery stenosis from fibromuscular dysplasia, neurofibromatosis type 1, Williams syndrome, or mid-aortic syndrome, is another important etiology. Coarctation of the aorta presents with upper extremity hypertension, diminished lower extremity pulses, and a blood pressure gradient between the arms and legs, and may present in infancy or childhood. Endocrine causes include pheochromocytoma, hyperthyroidism, Cushing syndrome, congenital adrenal hyperplasia, and primary aldosteronism (rare in children). Medications and substances such as corticosteroids, stimulants, oral contraceptives, caffeine, NSAIDs, and cocaine can also cause hypertension. Other causes include obstructive sleep apnea, increased intracranial pressure, Turner syndrome, and neurofibromatosis.

## Evaluation

### All Children with Confirmed Hypertension

A thorough history should address family history of hypertension, cardiovascular disease, chronic kidney disease, and endocrine disorders, as well as dietary habits including sodium intake, activity level, sleep history with attention to snoring and apnea, medication use, and symptoms of secondary causes. Physical examination should include four-extremity blood pressure measurement to exclude coarctation, growth parameters including BMI, fundoscopic examination, thyroid palpation, abdominal examination for renal masses and bruits, skin examination for neurofibromas, striae, acne, or hirsutism, genitalia assessment, and a neurologic exam. Basic laboratory studies include urinalysis, serum electrolytes, BUN, creatinine, CBC, fasting lipid panel, and fasting glucose. Renal ultrasound with Doppler evaluates renal size, echogenicity, and renal artery blood flow. Echocardiography assesses for left ventricular hypertrophy, the key marker of target organ damage, defined as left ventricular mass index greater than 51 g/m^2.7.

### Additional Evaluation for Suspected Secondary Hypertension

When renovascular disease is suspected, CTA or MRA of the renal arteries should be obtained, with catheter angiography serving as the gold standard for fibromuscular dysplasia. Endocrine evaluation includes plasma renin activity, aldosterone, plasma and urine metanephrines and catecholamines for pheochromocytoma, cortisol, and thyroid function tests. A sleep study (polysomnography) is indicated if obstructive sleep apnea is suspected. Renal biopsy may be necessary if glomerulonephritis or renal parenchymal disease is suspected.

<image>Diagnostic evaluation algorithm for pediatric hypertension, starting from confirmed elevated blood pressure measurements, branching into clinical assessment based on age, severity, and associated features, leading to tiered laboratory and imaging workup for primary versus secondary hypertension, with indicators for nephrology referral and further specialized testing</image>

## Management

### Lifestyle Modifications (First-Line for All)

Weight management targeting a BMI below the 85th percentile is recommended, as even modest weight reduction of 5-10% can lower blood pressure. A DASH-style diet emphasizing fruits, vegetables, whole grains, and low-fat dairy with sodium restriction (less than 2,300 mg/day for older children, less than 1,500 mg/day for those with CKD) is beneficial. Children should engage in 60 minutes of moderate-to-vigorous physical activity daily with sedentary screen time limited to less than 2 hours per day. Sleep optimization including adequate sleep duration and evaluation and treatment of sleep-disordered breathing is also important.

### Pharmacologic Therapy

Pharmacologic therapy is indicated for Stage 1 hypertension with symptoms or target organ damage such as LVH, Stage 2 hypertension, secondary hypertension, diabetes, CKD, or failure of lifestyle modifications after 6 months. The treatment goal is below the 90th percentile for children aged 1-13 years and below 130/80 for adolescents 13 years and older.

First-line agents include ACE inhibitors (lisinopril, enalapril), which are preferred for CKD, diabetes, and proteinuria but are contraindicated in pregnancy, necessitating counseling of sexually active adolescents. ARBs (losartan) serve as an alternative to ACE inhibitors with the same contraindications. Calcium channel blockers (amlodipine) are well tolerated and a good option when ACE inhibitors or ARBs are contraindicated. Thiazide diuretics (hydrochlorothiazide, chlorthalidone) are effective for primary hypertension.

Treatment should start at the lowest recommended dose and be titrated every 2-4 weeks to achieve the target blood pressure. If the response is inadequate at the maximum dose, a second agent from a different class should be added. Electrolytes and renal function should be monitored 1-2 weeks after starting ACE inhibitors or ARBs.

### Hypertensive Urgency and Emergency

Hypertensive urgency refers to severely elevated blood pressure without acute target organ damage, and blood pressure should be reduced gradually over 24-48 hours with oral agents. Hypertensive emergency involves severely elevated blood pressure with acute target organ damage such as encephalopathy, seizures, heart failure, retinal hemorrhage, or AKI, and requires ICU admission and IV antihypertensives. Preferred IV agents include nicardipine infusion (0.5-3 mcg/kg/min, the preferred continuous infusion), labetalol bolus or infusion, and hydralazine. The goal is to reduce blood pressure by no more than 25% in the first 8 hours, then gradually normalize over 24-48 hours, as rapid reduction risks cerebral ischemia.

## Sports Participation

There are no restrictions for Stage 1 hypertension without target organ damage once the evaluation is complete. Competitive sports, particularly heavy static exercises like weightlifting, should be restricted for Stage 2 hypertension until blood pressure is controlled and evaluation for secondary causes is complete. LVH from hypertension (pathologic) must be distinguished from athletic heart (physiologic).

## Clinical Pearls

Blood pressure should be measured at every healthcare encounter beginning at age 3 years, using an appropriately sized cuff on the right arm. Secondary causes are more likely in younger children, those with Stage 2 hypertension, and those with abnormal urinalysis or renal function. Coarctation of the aorta is diagnosed by comparing upper and lower extremity blood pressures, making four-extremity BP measurement essential in the initial evaluation. Left ventricular hypertrophy on echocardiography is the most important marker of target organ damage and an indication for pharmacologic therapy. Obesity is the strongest modifiable risk factor for primary hypertension in children, and lifestyle interventions are the foundation of treatment. In hypertensive emergencies, blood pressure should be reduced by no more than 25% in the first 8 hours to avoid cerebral hypoperfusion.

## References

1. Flynn JT, Kaelber DC, Baker-Smith CM, et al. Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents. *Pediatrics*. 2017;140(3):e20171904.
2. Lurbe E, Agabiti-Rosei E, Cruickshank JK, et al. 2016 European Society of Hypertension guidelines for the management of high blood pressure in children and adolescents. *Journal of Hypertension*. 2016;34(10):1887-1920.
3. Brady TM, Feld LG. Pediatric approach to hypertension. *Seminars in Nephrology*. 2009;29(4):379-388.
4. 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(2 Suppl 4th Report):555-576.