Overview

Definition:
-Pediatric hypertension is defined as an average systolic and/or diastolic blood pressure that is greater than or equal to the 95th percentile for age, sex, and height on three or more occasions
-This definition is based on established reference values, such as those from the Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents
-Isolated elevated readings during a single clinic visit do not confirm the diagnosis
-serial measurements are crucial
-Primary (essential) hypertension is increasingly recognized in children, but secondary causes remain common and are often treatable.
Epidemiology:
-The prevalence of hypertension in children and adolescents varies widely depending on the population studied and the diagnostic criteria used, ranging from 1% to over 5%
-Primary hypertension accounts for the majority of cases in older children and adolescents, while secondary hypertension is more prevalent in younger children and infants
-Obesity is a significant risk factor for primary hypertension in pediatric populations
-Untreated hypertension in childhood can lead to long-term cardiovascular complications, including left ventricular hypertrophy, chronic kidney disease, and stroke.
Clinical Significance:
-Recognizing and managing hypertension in children is critical for preventing irreversible end-organ damage and reducing the risk of premature cardiovascular disease in adulthood
-Early identification and intervention can significantly alter the long-term health trajectory of affected individuals
-A thorough understanding of secondary causes is paramount, as their prompt diagnosis and treatment can lead to complete resolution of hypertension
-Ambulatory Blood Pressure Monitoring (ABPM) plays a vital role in accurate diagnosis and management.

Diagnostic Approach

History Taking:
-A comprehensive history should focus on identifying risk factors for primary hypertension and clues to secondary causes
-Key elements include: Family history of hypertension, cardiovascular disease, or kidney disease
-Detailed birth history (prematurity, intrauterine growth restriction, perinatal complications)
-Diet and lifestyle (high sodium intake, obesity, physical inactivity, sweetened beverage consumption)
-Symptoms suggestive of secondary causes: headaches, visual disturbances, epistaxis (pheochromocytoma, renal artery stenosis)
-Abdominal masses or bruits (neuroblastoma, Wilms tumor, renal artery stenosis)
-Weak or absent femoral pulses (coarctation of the aorta)
-Polydipsia, polyuria, failure to thrive (renal disease, endocrine disorders)
-Medication use (steroids, sympathomimetics, oral contraceptives)
-Red flags include hypertension in infants/young children, very high blood pressure readings, hypertension resistant to multiple medications, and signs of end-organ damage.
Physical Examination:
-A systematic physical examination is essential
-It should include: Accurate measurement of blood pressure in both arms and legs (especially if coarctation is suspected), using appropriately sized cuffs
-Growth assessment (height, weight, BMI, plotting on growth charts)
-Cardiovascular examination (murmurs, gallops, peripheral pulses, checking for coarctation of the aorta by comparing upper and lower extremity BP)
-Abdominal examination (palpable masses, bruits)
-Funduscopic examination (hypertensive retinopathy)
-Neurological examination (if indicated by symptoms)
-Examination for stigmata of specific syndromes (e.g., Cushingoid features, ambiguous genitalia).
Investigations:
-Initial investigations aim to confirm hypertension, identify target organ damage, and screen for common secondary causes: **Blood Pressure Measurement:** Serial BP measurements in a quiet environment using calibrated devices
-**Ambulatory Blood Pressure Monitoring (ABPM):** The gold standard for diagnosing sustained hypertension, evaluating diurnal BP patterns, and identifying white-coat hypertension or masked hypertension
-It involves automated BP measurements every 15-30 minutes during the day and every 30-60 minutes at night over a 24-hour period
-Normal daytime BP < 90th percentile, nocturnal dipping of 10-20%
-**Laboratory Tests:** Urinalysis (proteinuria, hematuria, glucosuria)
-Basic metabolic panel (serum creatinine, electrolytes, BUN) to assess renal function and electrolyte balance
-Complete blood count
-Lipid profile
-Fasting blood glucose or HbA1c
-**Screening for Secondary Causes:** **Renal Ultrasound:** To assess kidney size, structure, and rule out structural abnormalities
-**Renal Artery Doppler Ultrasound:** To screen for renal artery stenosis
-**Echocardiogram:** To assess for left ventricular hypertrophy and other cardiac abnormalities
-**Hormonal Assays (if indicated):** Plasma renin activity, aldosterone levels (primary aldosteronism)
-urine or plasma catecholamines and metanephrines (pheochromocytoma)
-serum cortisol, dexamethasone suppression test (Cushing's syndrome)
-17-hydroxyprogesterone (congenital adrenal hyperplasia)
-**Imaging for specific causes:** CT or MRI of abdomen/pelvis (neuroblastoma, Wilms tumor)
-aortography or CT angiography (coarctation of aorta, renal artery stenosis).
Differential Diagnosis:
-The differential diagnosis for hypertension in children includes: **Primary (Essential) Hypertension:** Increasingly common, often associated with obesity and family history
-**Secondary Hypertension:** A broad category including: **Renal Parenchymal Disease:** Glomerulonephritis, polycystic kidney disease, reflux nephropathy
-**Renovascular Hypertension:** Renal artery stenosis (atherosclerotic, fibromuscular dysplasia, congenital)
-**Endocrine Disorders:** Primary aldosteronism, Cushing's syndrome, pheochromocytoma, congenital adrenal hyperplasia, hyperthyroidism, hypothyroidism
-**Vascular Abnormalities:** Coarctation of the aorta, aberrant subclavian artery
-**Neurologic Disorders:** Increased intracranial pressure, Guillain-Barré syndrome
-**Medications:** Steroids, sympathomimetics, oral contraceptives
-**Obstructive Sleep Apnea:** A common contributor to resistant hypertension
-**Genetic Syndromes:** Williams syndrome, neurofibromatosis
-Distinguishing features often lie in the age of onset, severity of hypertension, presence of specific symptoms, and physical examination findings.

Ambulatory Blood Pressure Monitoring

Purpose:
-ABPM is crucial for confirming the diagnosis of sustained hypertension, differentiating it from white-coat hypertension, identifying masked hypertension, and assessing the effectiveness of antihypertensive therapy
-It provides a more comprehensive picture of a child's BP profile than office readings alone.
Indications:
-Indications for ABPM in children include: Suspected white-coat hypertension (elevated clinic BP with normal home/ambulatory readings)
-Suspected masked hypertension (normal clinic BP with elevated home/ambulatory readings)
-Evaluation of resistant hypertension (BP above target despite ≥3 antihypertensive medications, including a diuretic)
-Assessment of nocturnal dipping patterns
-Monitoring antihypertensive treatment efficacy
-Hypertension in children with specific comorbidities like diabetes or chronic kidney disease.
Interpretation:
-ABPM data is interpreted by comparing average daytime, nighttime, and 24-hour BP readings to age-, sex-, and height-specific percentile charts
-Key parameters include: **Average systolic and diastolic BP:** Compared to percentiles for age, sex, and height
-**Blood Pressure Load:** Percentage of readings above the 95th percentile
-**Diurnal Variation:** The normal pattern involves a significant drop in BP during sleep (nocturnal dipping), typically 10-20%
-Non-dippers or extreme dippers may have increased cardiovascular risk
-**Masked Hypertension:** Normal clinic BP, elevated 24-hour ABPM
-**White-Coat Hypertension:** Elevated clinic BP, normal 24-hour ABPM
-**Sustained Hypertension:** Elevated clinic BP and elevated 24-hour ABPM.

Secondary Causes Of Hypertension

Renal Parenchymal Disease:
-Common causes include chronic glomerulonephritis, polycystic kidney disease, and chronic pyelonephritis
-These conditions lead to impaired sodium excretion and activation of the renin-angiotensin-aldosterone system (RAAS)
-Diagnosis relies on urinalysis, renal function tests, and renal imaging.
Renovascular Hypertension:
-Narrowing of the renal arteries reduces blood flow to the kidneys, stimulating RAAS
-Causes include fibromuscular dysplasia (most common in children and young adults) and atherosclerosis
-Key features are often severe hypertension, a renal artery bruit, and electrolyte abnormalities (hypokalemia with secondary hyperaldosteronism)
-Diagnosis is made via Doppler ultrasound, CT angiography, or MR angiography.
Endocrine Disorders:
-These include primary aldosteronism (Conn's syndrome), Cushing's syndrome, pheochromocytoma, congenital adrenal hyperplasia, and hyperthyroidism
-Each has specific hormonal profiles and clinical manifestations that guide diagnosis through targeted laboratory testing and imaging.
Coarctation Of The Aorta:
-A congenital narrowing of the aorta, typically distal to the left subclavian artery
-Presents with hypertension in the upper extremities and hypotension in the lower extremities, with diminished or absent femoral pulses
-A continuous or systolic murmur may be heard in the back
-Diagnosis is confirmed by echocardiography or cross-sectional imaging.
Other Causes:
-These encompass genetic syndromes (e.g., Williams syndrome), neurological disorders, and various medications
-A thorough history and physical examination, guided by suspected etiologies, are key to identifying these less common but treatable causes.

Management

Initial Management:
-The initial management involves lifestyle modifications and pharmacological therapy
-Lifestyle changes are fundamental and include dietary adjustments (reduced sodium intake, DASH diet), weight management, increased physical activity, and smoking cessation (for adolescents)
-Pharmacological therapy is initiated based on the BP level and the presence of target organ damage or comorbidities
-The choice of antihypertensive medication depends on the child's age, race, and the presence of secondary causes.
Medical Management:
-Antihypertensive drug classes recommended for children include: **Diuretics:** Thiazide diuretics (e.g., hydrochlorothiazide, chlorthalidone) are often first-line agents, especially for primary hypertension
-**ACE inhibitors (ACEIs) and Angiotensin II Receptor Blockers (ARBs):** Effective and well-tolerated, particularly useful in children with proteinuria or diabetes
-Examples: Lisinopril, Enalapril (ACEIs)
-Losartan, Valsartan (ARBs)
-**Calcium Channel Blockers (CCBs):** Dihydropyridines (e.g., amlodipine) are effective for managing systolic hypertension
-Non-dihydropyridines (e.g., diltiazem, verapamil) can also be used, especially if there is concomitant tachycardia or supraventricular arrhythmias
-**Beta-blockers:** Less commonly used as first-line agents unless there is a specific indication like congenital heart disease or hypertrophic cardiomyopathy
-Examples: Metoprolol, Atenolol
-**Dosage adjustments are crucial** based on age, weight, and response
-Treatment of secondary causes often resolves the hypertension, but some may require concurrent antihypertensive therapy.
Management Of Secondary Causes:
-The management strategy is dictated by the specific secondary cause
-**Renal artery stenosis:** Angioplasty or surgical revascularization may be considered
-**Coarctation of the aorta:** Surgical repair or balloon angioplasty
-**Pheochromocytoma:** Surgical resection, often preceded by alpha-adrenergic blockade
-**Primary aldosteronism:** Aldosterone antagonists (spironolactone, eplerenone)
-**Cushing's syndrome:** Surgical removal of the tumor or medical management to reduce cortisol production
-Prompt identification and treatment of these causes can lead to normalization of blood pressure and prevent long-term complications.

Complications

Target Organ Damage:
-Untreated or poorly controlled hypertension can lead to significant end-organ damage in children, mirroring adult complications
-This includes: **Cardiovascular System:** Left ventricular hypertrophy (LVH), diastolic dysfunction, premature coronary artery disease, heart failure
-**Renal System:** Proteinuria, hematuria, chronic kidney disease, end-stage renal disease
-**Cerebrovascular System:** Stroke (ischemic or hemorrhagic), transient ischemic attacks
-**Ocular System:** Hypertensive retinopathy (retinal hemorrhages, exudates, papilledema).
Long Term Sequelae:
-Children with hypertension are at increased risk for developing sustained hypertension into adulthood, significantly raising their lifetime risk of cardiovascular events like myocardial infarction, stroke, and aortic dissection
-Early detection and aggressive management can mitigate these long-term risks.
Prevention Strategies:
-Prevention focuses on addressing modifiable risk factors from an early age: promoting healthy dietary habits (low sodium, fruits, vegetables), encouraging regular physical activity, maintaining a healthy weight, and avoiding exposure to tobacco smoke
-Early screening for hypertension in at-risk children (e.g., those with obesity, family history, or congenital anomalies) is also crucial.

Key Points

Exam Focus:
-Understand the definition of hypertension in children based on percentiles
-Master the indications and interpretation of ABPM
-Differentiate primary vs
-secondary hypertension based on age and clinical features
-Recognize common secondary causes and their key diagnostic clues (renal, endocrine, vascular)
-Know the first-line antihypertensive agents for children
-Recognize the importance of lifestyle modifications.
Clinical Pearls:
-Always measure BP in both arms and legs in suspected cases of coarctation
-Consider ABPM for any child with borderline elevated clinic BP or resistant hypertension
-Think secondary cause in very young children or those with sudden onset of severe hypertension
-Don't forget obstructive sleep apnea as a contributor to resistant hypertension
-Treat the underlying secondary cause whenever possible for a potential cure.
Common Mistakes:
-Diagnosing hypertension based on a single elevated reading
-Using adult BP cuff sizes on children
-Underestimating the prevalence of primary hypertension in older children/adolescents
-Failing to investigate for secondary causes when indicated
-Inadequate dosage titration of antihypertensive medications
-Neglecting the importance of lifestyle modifications in management.