# Hypertension: Pediatric Onset to Adult Consequences

## Overview
Hypertension in children is defined using normative percentile tables based on age, sex, and height, whereas adult hypertension uses fixed thresholds. Mounting evidence demonstrates that elevated blood pressure in childhood tracks into adulthood and contributes to early cardiovascular disease. The Med-Peds physician must bridge these diagnostic frameworks and understand the continuum of hypertension across the lifespan.

## Definitions and Classification

### Pediatric Hypertension (AAP 2017 Guidelines, ages 1-13)
**Normal BP**: <90th percentile for age/sex/height. **Elevated BP**: >=90th percentile to <95th percentile, OR 120/80 mmHg to <95th percentile (whichever is lower) **Stage 1 HTN**: >=95th percentile to <95th percentile + 12 mmHg, OR 130/80 to 139/89 mmHg (whichever is lower) **Stage 2 HTN**: >=95th percentile + 12 mmHg, OR >=140/90 mmHg (whichever is lower) For adolescents >=13 years: adult thresholds apply (ACC/AHA 2017)

### Adult Hypertension (ACC/AHA 2017 Guidelines)
**Normal**: <120/<80 mmHg. **Elevated**: 120-129/<80 mmHg. **Stage 1 HTN**: 130-139/80-89 mmHg. **Stage 2 HTN**: >=140/>=90 mmHg. **Hypertensive crisis**: >180/>120 mmHg (urgency without end-organ damage; emergency with end-organ damage)

### Key Differences
Pediatric BP must be interpreted using normative tables (available in the 2017 AAP guideline, simplified screening table provided) Simplified screening: if BP >=120/80 at any age, it is at least elevated. Measurement technique is critical: proper cuff size (bladder width 40% of arm circumference, length 80-100%), seated quietly for 3-5 minutes, right arm preferred, auscultatory confirmation of oscillometric readings.

## Epidemiology and Tracking

### Pediatric Prevalence
Primary (essential) hypertension: 3-5% of children and adolescents. Rising prevalence correlates with increasing childhood obesity. Previously, secondary hypertension was more common in children; now primary HTN predominates in adolescents.

### Blood Pressure Tracking
Children in the highest BP percentiles are significantly more likely to become hypertensive adults. The Bogalusa Heart Study and Muscatine Study demonstrate that childhood BP is a strong predictor of adult BP and cardiovascular risk. Target organ damage (left ventricular hypertrophy, increased carotid intima-media thickness) begins in childhood.

## Evaluation

### When to Suspect Secondary Hypertension
**All children** <6 years with HTN should undergo secondary HTN workup. **Older children/adolescents** if Stage 2 HTN, resistant HTN, or clinical features suggest a secondary cause. **Adults**: secondary HTN accounts for 5-10% of cases; evaluate if onset <30 or >55, resistant HTN, or clinical clues.

### Secondary Causes by Age

| Age Group | Common Causes |
|-----------|--------------|
| Neonates | Renal artery thrombosis, renal artery stenosis, coarctation of aorta, congenital kidney disease |
| 1-6 years | Renal parenchymal disease, renal artery stenosis, coarctation of aorta, Wilms tumor |
| 6-12 years | Renal parenchymal disease, primary HTN (especially if obese), endocrine (rare) |
| Adolescents | Primary HTN, renal parenchymal disease, substance use |
| Young adults | Primary HTN, fibromuscular dysplasia (especially women), OCP-related, pheochromocytoma |
| Adults | Primary HTN, renal artery stenosis (atherosclerotic), primary aldosteronism, OSA, thyroid disease |

### Workup

#### All Children with Confirmed HTN
Basic metabolic panel (BMP) with electrolytes, BUN, creatinine; Urinalysis and urine culture; CBC; Lipid panel and fasting glucose (if obese); Renal ultrasound with Doppler; Echocardiogram (assess for LVH and coarctation).

#### Additional Studies as Indicated
Plasma renin and aldosterone: renovascular HTN, primary aldosteronism; Urine catecholamines/metanephrines: pheochromocytoma; Thyroid function tests; CTA/MRA of renal arteries: if high suspicion of renovascular disease; Drug screening in adolescents; Sleep study if OSA suspected.

#### Adults
BMP, urinalysis, lipid panel, fasting glucose/HbA1c, TSH, CBC. Renal artery duplex ultrasound or CTA if renovascular HTN suspected. Aldosterone/renin ratio if hypokalemia or resistant HTN (screen for primary aldosteronism) Echocardiogram if LVH suspected or for risk stratification. Ambulatory blood pressure monitoring (ABPM) for white coat and masked HTN.

## Management

### Lifestyle Modifications (All Ages)
Dietary: DASH diet principles (fruits, vegetables, low-fat dairy, reduced sodium) Pediatric sodium restriction: <2300 mg/day (further restrict to <1500 mg if HTN confirmed) Adult: <2300 mg/day (ideally <1500 mg/day per AHA) Physical activity: 60 minutes/day moderate-to-vigorous for children; 150 min/week for adults. Weight management: even 5-10% weight loss significantly reduces BP. Limit screen time, improve sleep in children. Smoking cessation, alcohol moderation in adults.

### Pharmacotherapy in Children
**Indications**: Stage 2 HTN, Stage 1 HTN with symptoms or target organ damage, HTN with diabetes or CKD, failure of lifestyle modification after 6 months. **First-line agents**: ACE inhibitors (lisinopril, enalapril): preferred if proteinuria, diabetes, or CKD. ARBs (losartan): alternative to ACEi; both contraindicated in pregnancy. Calcium channel blockers (amlodipine): safe and effective; good for younger children (liquid formulation) Thiazide diuretics (chlorthalidone, HCTZ): less commonly first-line in children. **Goal**: <90th percentile (or <130/80 in adolescents >=13) Start low, titrate every 2-4 weeks, monitor electrolytes and renal function.

### Pharmacotherapy in Adults
**Stage 1 HTN**: lifestyle modification first; add medication if 10-year ASCVD risk >=10%. **Stage 2 HTN**: lifestyle + medication (often two-drug combination) **First-line agents**: ACEi/ARB, CCB, thiazide diuretic. **Compelling indications**: CHF: ACEi/ARB + beta-blocker + diuretic + aldosterone antagonist; Post-MI: ACEi + beta-blocker; DM with proteinuria: ACEi/ARB; CKD: ACEi/ARB; Resistant HTN (uncontrolled on 3 agents including diuretic): add spironolactone (PATHWAY-2 trial) **Goal**: <130/80 mmHg for most adults per ACC/AHA 2017.

### Hypertensive Emergencies

#### Pediatric
BP >95th percentile + 12 mmHg WITH end-organ damage (encephalopathy, seizures, heart failure, retinopathy) IV agents: nicardipine infusion (0.5-3 mcg/kg/min, preferred), labetalol IV, hydralazine IV. Goal: reduce BP by no more than 25% in first 8 hours, then gradually normalize over 24-48 hours. Avoid rapid reduction: risk of watershed cerebral infarction.

#### Adult
BP >180/120 WITH end-organ damage. IV agents: nicardipine, clevidipine, nitroprusside, labetalol, esmolol (agent choice depends on clinical scenario) Same 25% reduction principle in first hour; specific targets for aortic dissection (HR <60, SBP <120)

<image>A diagnostic flowchart for pediatric hypertension evaluation. Starting with blood pressure measurement showing proper cuff sizing and patient positioning, the chart branches based on whether BP is above the 90th, 95th, or 95th + 12 mmHg percentile thresholds. Each branch leads to recommended actions: repeat measurement for elevated BP, initiate workup for Stage 1 (lifestyle modification then medication), and urgent evaluation for Stage 2 (labs, renal ultrasound, echocardiogram, consider secondary causes). A sidebar lists age-specific secondary causes from neonates to adolescents.</image>

<image>A longitudinal tracking diagram showing blood pressure percentile trajectories from childhood through adulthood. Three curves are shown: one child consistently at the 50th percentile (remains normotensive as an adult), one at the 75th percentile (develops elevated BP as a young adult), and one at the 95th percentile (develops Stage 1 hypertension by age 25 with evidence of LVH on echocardiogram). Data points from the Bogalusa Heart Study are annotated, emphasizing that childhood BP predicts adult cardiovascular risk.</image>

<image>A comparison infographic of first-line antihypertensive agents in children versus adults. Four drug classes (ACE inhibitors, ARBs, calcium channel blockers, thiazide diuretics) are shown with pediatric and adult dosing ranges, preferred clinical scenarios, contraindications, and monitoring requirements. Icons highlight key safety points: teratogenicity warning for ACEi/ARBs, electrolyte monitoring for diuretics, and peripheral edema with CCBs.</image>

## Clinical Pearls
Use the simplified AAP screening table: any BP >=120/80 in a child of any age is at least elevated and warrants further evaluation. Proper cuff size is critical -- using a cuff that is too small will falsely elevate readings (the most common source of error) All children with confirmed hypertension should have a renal ultrasound and echocardiogram. Childhood BP tracks into adulthood -- addressing elevated BP in a 10-year-old may prevent cardiovascular disease decades later. In adolescents >=13 years, use adult thresholds (130/80) per both AAP and ACC/AHA guidelines. Primary aldosteronism is the most common cause of secondary HTN in adults -- screen with aldosterone/renin ratio if resistant HTN or unexplained hypokalemia. Amlodipine is an excellent first-line agent in young children because it is available in liquid formulation and does not require electrolyte monitoring. Never reduce BP by more than 25% in the first 8 hours during a hypertensive emergency (pediatric or adult) -- rapid reduction risks watershed infarction.

## References
- 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.
- Whelton PK, Carey RM, Aronow WS, et al. 2017 ACC/AHA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults. J Am Coll Cardiol. 2018;71(19):e127-e248.
- Chen X, Wang Y. Tracking of blood pressure from childhood to adulthood: a systematic review and meta-regression analysis. Circulation. 2008;117(25):3171-3180.
- 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. J Hypertens. 2016;34(10):1887-1920.
- Williams B, MacDonald TM, Morant S, et al. Spironolactone versus placebo, bisoprolol, and doxazosin to determine the optimal treatment for drug-resistant hypertension (PATHWAY-2). Lancet. 2015;386(10008):2059-2068.