Hypertension

Basics

Description

  • Hypertension: average systolic and/or diastolic blood pressure (BP) at or above the 95th percentile for age, gender, and height percentile or ≥130/80 mm Hg in adolescents ≥13 years of age
  • Elevated BP: BP between the 90th and 95th percentile or BP 120–129/<80 mm Hg in adolescents ≥13 years of age
  • Stage 1 hypertension: BP ≥95th percentile to 95th percentile plus 12 mm Hg or BP 130–139/80–89 mm Hg in adolescents ≥13 years of age
  • Stage 2 hypertension: BP ≥95th percentile plus 12 mm Hg or ≥BP 140/90 mm Hg in adolescents ≥13 years of age
  • Primary (essential) hypertension: hypertension for which there is no underlying cause
  • Secondary hypertension: hypertension for which an underlying cause can be identified
  • White coat hypertension: elevated BP readings in a medical setting with normal BP on ambulatory blood pressure monitoring (ABPM)
  • Masked hypertension: normal BP readings in a medical setting with elevated BP readings on ABPM

Epidemiology

  • Primary hypertension is now frequently identified in children and adolescents and is associated with overweight status, metabolic syndrome, and family history of hypertension.
  • The prevalence of hypertension is increasing due to the epidemic of youth obesity and the metabolic syndrome.
  • Hypertension in the pediatric population is estimated to be between 1% and 4%.
  • 30% of children with body mass index (BMI) >95% have prehypertension or hypertension.

Risk Factors

  • Primary hypertension: obesity, sedentary lifestyle, low birth weight, smoking, alcohol use, hyperlipidemia, family history, stress, sodium intake, sleep apnea
  • Secondary hypertension: renal or urologic disease, transplant, congenital heart disease, umbilical artery catheterization, urinary tract infection (UTI), diabetes mellitus, elevated intracranial pressure, or medications known to raise BP

Genetics

  • The genetic basis of primary hypertension is polygenic but more likely to develop in individuals when there is a strong family history.
  • The genetics of secondary causes depend on the underlying condition, for example:
    • Polycystic kidney disease: autosomal dominant, autosomal recessive
    • Neurofibromatosis: autosomal dominant
    • Glucocorticoid-remediable aldosteronism: autosomal dominant

General Prevention

Avoidance of excess weight gain and regular physical activity can prevent obesity-related hypertension.

Etiology

Secondary causes

  • Renal: acute glomerulonephritis, chronic renal failure, polycystic kidney disease, reflux nephropathy
  • Renovascular: fibromuscular dysplasia, neurofibromatosis, vasculitis
  • Cardiac: coarctation of the aorta
  • Endocrine: pheochromocytoma, hypo/hyperthyroid, neuroblastoma, glucocorticoid-remediable aldosteronism, Conn syndrome, apparent mineralocorticoid excess, congenital adrenal hyperplasia, Liddle syndrome, Gordon syndrome
  • Neurologic: increased intracranial pressure
  • Drugs: corticosteroids, oral contraceptives, sympathomimetics, illicit drugs (cocaine, phencyclidine)
  • Other: pain, burns, traction
  • Reduced nephron number secondary to premature birth, low birth weight, or postnatal insults are associated with hypertension.

Pathophysiology

BP is a product of cardiac output and total peripheral vascular resistance. Increases of either or both of these products lead to hypertension. The various causes of hypertension alter BP through different mechanisms such as volume overload (sodium retention, excess sodium intake), volume distribution, renin-angiotensin excess, sympathetic activation, insulin, and endothelin.

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