Hypertension

Elevated blood pressure (BP) in childhood is associated with an increased risk of hypertension in adulthood and increased cardiovascular risk.

Definition and Blood-Pressure Measurement

Definition: Hypertension is defined as an elevated BP (see table below) for a child’s age, gender, and stature confirmed on three or more separate occasions.

• Epidemiologic studies indicate that children commonly have BP reduction between the first and subsequent BP readings, likely due to acclimation to the BP cuff and reduced anxiety.

• The definitions for elevated BP and hypertension were refined in the 2017 American Academy of Pediatrics (AAP) Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents. These guidelines update the normative BP values for children, which had previously included measurements from overweight and obese children who are known to be at a higher risk for hypertension.

Blood-Pressure measurement in children: Although automated BP measurements are acceptable for screening, all elevated BPs should be confirmed using manual auscultation.

• BP should be measured in an upper extremity, with the cuff placed at the midpoint between the acromion and olecranon. The bladder length of the cuff should encircle 80%-100% of the arm circumference and the bladder width should encircle about 40% of the arm circumference.

• In an ideal environment, BP should be measured when the child is quiet and sitting upright with back supported, legs uncrossed, and feet on the floor.

• Assess if the child is anxious or may have consumed caffeinated beverages prior to BP measurement because these may affect the reading. Consider ambulatory blood pressure monitoring (ABPM) if “white coat hypertension” is suspected (reported in up to 30%-40% of adolescents referred for hypertension evaluation).

Etiology

Hypertension in children can be defined as primary (having no obvious etiology) or secondary (due to an identifiable cause). Although primary hypertension is the most common etiology among all pediatric hypertension referrals in the United States, hypertension in infants and younger children is more often due to secondary causes. Obesity-related hypertension has become more common across all ages as a result of the obesity epidemic in the United States and can be associated with other cardiovascular risk factors, including hyperlipidemia and diabetes mellitus.

Secondary causes of hypertension include the following:

• renal parenchymal disease/structural abnormalities

  • congenital anomalies of the kidney and urinary tract (CAKUT)

  • glomerulonephritis

  • renal scarring (most commonly due to recurrent untreated urinary tract infection or pyelonephritis, even if treated)

• vascular/renovascular disease

  • coarctation of aorta

  • renal artery stenosis

  • thrombotic microangiopathy (e.g., in hemolytic-uremic syndrome or thrombotic thrombocytopenic purpura)

  • renal vein/artery thrombosis

  • vasculitis

• endocrine disorders

  • hyperthyroidism

  • Cushing syndrome

  • pheochromocytomas and paragangliomas

• genetic conditions

  • monogenic hypertension (Liddle syndrome, Gordon syndrome, glucocorticoid-remediable aldosteronism)

  • genetic syndromes (neurofibromatosis 1, Williams syndrome, tuberous sclerosis, Turner syndrome)

• medications

  • glucocorticoids

  • stimulants (e.g., amphetamines, caffeine)

  • over-the-counter cough/cold preparations containing phenylephrine or pseudoephedrine

  • combined oral contraceptive pills

• complications of pregnancy

  • pregnancy-induced hypertension

  • preeclampsia

Evaluation

The first step in the evaluation of hypertension is confirmation that the child has true BP elevation by measuring on multiple occasions.

• Consider 24-hour ambulatory BP monitoring if discrepancies are found between BP measurements in different clinical settings, if the patient has anxiety (white coat hypertension), or if you suspect masked hypertension (normal BP in clinic but elevated outside of clinic).

• Once hypertension is confirmed, further clinical evaluation is guided by patient characteristics to assess for secondary causes and for potential sequelae of hypertension as described in the following table:

Based on the 2017 AAP Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents, an extensive evaluation for secondary causes of hypertension is not necessary in children age 6 years and older who meet the following criteria:

• positive family history of hypertension

• history of overweight or obesity

• no history/physical exam findings suggestive of secondary hypertension (see Table 14 in the AAP guideline, Examples of Physical Examination Findings and History Suggestive of Secondary HTN or Related to End Organ Damage Secondary to HTN)

Once hypertension is confirmed, assess for signs of target organ damage:

• echocardiogram (left ventricular hypertrophy)

• urinalysis (microalbuminuria)

• dilated eye exam (papilledema, hypertensive nicking)

Treatment

• Lifestyle modifications: For all children, particularly those with obesity-related hypertension, dietary changes and increased physical activity are the cornerstone of BP reduction.

  • The Dietary Approach to Stop Hypertension (DASH) Eating Plan: The DASH diet involves increased fruit and vegetable intake and lower total sodium intake; it is also helpful for management of hyperlipidemia.

  • If history raises concern for obstructive sleep apnea (OSA), consider ordering a sleep study. If the patient is diagnosed with OSA, continuous positive airway pressure therapy (CPAP) may help reduce BP.

• Pharmacologic agents: These are reserved for children with proven secondary causes of hypertension or for whom lifestyle modification does not normalize BP.

  • Ideally, the choice of agent used should be targeted to the mechanism of the patient’s hypertension. For example:

    • Renovascular hypertension: angiotensin-converting-enzyme (ACE) inhibitors, angiotensin-receptor blockers (ARBs)

    • Fluid-retaining states (e.g., glucocorticoid-induced hypertension): thiazide diuretics

    • Coarctation of aorta: beta-blockade

    • Chronic kidney disease: ACE inhibitors, ARBs

  • A second agent should not be added until the first agent is maximized or side effects develop, whichever comes first.

  • For an acute hypertensive crisis, fast-acting BP-lowering agents such as intravenous (IV) hydralazine and labetalol should be used with a goal of lowering BP by no more than 25% of peak BP over the first 24 hours.

    • An abrupt decrease in BP can cause an acute drop in cerebral perfusion pressure and lead to ischemic stroke.

    • If standing IV doses do not adequately capture the BP, the child should be put on an antihypertensive drip (e.g., nicardipine, labetalol).