Full Answer Section

1. Thorough Physical Examination:

   • Accurate Blood Pressure Measurement: Ensure proper cuff size and technique. Obtain multiple readings during the visit and ideally on different extremities. Compare to age, sex, and height-specific norms.
   • Growth Parameters: Height, weight, and head circumference plotted on growth charts to assess for growth failure or obesity.
   • General Appearance: Assess for signs of underlying conditions (e.g., facial features suggestive of Cushing’s syndrome or neurofibromatosis).
   • Cardiovascular Examination: Auscultate heart sounds for murmurs, assess peripheral pulses.
   • Abdominal Examination: Palpate for enlarged kidneys or masses. Auscultate for renal artery bruits.
   • Neurological Examination: Assess for any focal deficits.
   • Skin Examination: Look for skin lesions suggestive of neurofibromatosis or other syndromes.

2. Laboratory Investigations:

   • Urinalysis: To screen for proteinuria, hematuria, and infection. Consider a first morning void.
   • Serum Electrolytes, Creatinine, BUN: To assess renal function.
   • Blood Glucose: To screen for diabetes.
   • Lipid Profile: To assess for dyslipidemia.
   • Renin and Aldosterone Levels: Especially if there is suspicion of renovascular disease or primary aldosteronism. Obtain these with the child in a standardized position and hydration status.
   • Thyroid Function Tests (TSH, Free T4): To rule out thyroid disorders.
   • Complete Blood Count (CBC): To assess for anemia or other hematological abnormalities.
   • Calcium and Phosphate: To screen for parathyroid disorders.
   • Plasma Metanephrines and Normetanephrines (or 24-hour urine catecholamines and metanephrines): To screen for pheochromocytoma, especially if there are episodic symptoms like headaches, sweating, and palpitations.

3. Imaging Studies:

   • Renal Ultrasound: To assess kidney size, structure, and rule out hydronephrosis, masses, or other renal abnormalities. Doppler studies can assess renal artery blood flow.
   • Echocardiogram: To evaluate cardiac structure and function, and rule out coarctation of the aorta (though this often presents earlier, it should be considered).
   • Renal Scintigraphy (e.g., MAG3 scan): May be indicated if there is suspicion of renovascular disease or differential renal function.
   • Abdominal CT or MRI: May be considered if renal ultrasound is abnormal or to further evaluate for other intra-abdominal masses or endocrine tumors.
   • Cranial MRI: If there are neurological symptoms or suspicion of intracranial hypertension.

Differential Diagnoses:

• Renal Parenchymal Disease: Glomerulonephritis, pyelonephritis, polycystic kidney disease, renal dysplasia, obstructive uropathy.
• Renovascular Disease: Renal artery stenosis (fibromuscular dysplasia, neurofibromatosis type 1).
• Coarctation of the Aorta: Although usually detected earlier, especially with upper-lower extremity blood pressure discrepancies.
• Endocrine Disorders: Hyperaldosteronism (primary or secondary), pheochromocytoma, Cushing’s syndrome, hyperthyroidism, hyperparathyroidism.
• Obesity-Related Hypertension: Increasingly common, even in young children.
• Medication-Induced Hypertension: Stimulants, corticosteroids, decongestants.
• Sleep Apnea: Can be associated with hypertension.
• Essential Hypertension: Less common in this age group but becomes more likely with increasing age and a strong family history.

Assessment:

Based on the history, physical exam, and initial investigations, I would categorize the hypertension according to the 2017 American Academy of Pediatrics (AAP) Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents: ¹  

• Normal Blood Pressure: Below the 90th percentile for age, sex, and height.
• Elevated Blood Pressure: Between the 90th and <95th percentile, or 120/80 mmHg to <95th percentile (whichever is lower).
• Stage 1 Hypertension: Between the 95th percentile to <95th percentile + 12 mmHg, or 130/80 to 139/89 mmHg (whichever is lower).
• Stage 2 Hypertension: ≥95th percentile + 12 mmHg, or ≥140/90 mmHg (whichever is lower).

Given the documented hypertension on three visits in a 3-year-old, this likely falls into Stage 1 or Stage 2 hypertension, requiring further investigation for secondary causes.

Management:

The management plan will depend heavily on the underlying cause identified.

1. Non-Pharmacological Management (Initial Steps and Adjunctive Therapy):

   • Lifestyle Modifications:
     • Healthy Diet: Emphasize a diet rich in fruits, vegetables, and whole grains, with limited processed foods, sugary drinks, and sodium intake. Educate parents on age-appropriate portion sizes.
     • Regular Physical Activity: Encourage at least 60 minutes of moderate-to-vigorous physical activity daily, tailored to the child’s developmental stage and abilities.
     • Weight Management: If the child is overweight or obese, implement strategies for gradual and healthy weight loss in consultation with a registered dietitian.
   • Accurate Blood Pressure Monitoring at Home: Educate parents on proper technique and the importance of regular monitoring.

2. Pharmacological Management:

   • Antihypertensive Medications: Given the likelihood of secondary hypertension in a 3-year-old, medication is often necessary while the underlying cause is being investigated and addressed. The choice of medication will depend on the suspected etiology and the child’s overall health.
     • ACE inhibitors or Angiotensin Receptor Blockers (ARBs): Often used if renal parenchymal disease or renovascular disease is suspected (use with caution in bilateral renal artery stenosis).
     • Beta-blockers: May be considered if there is associated tachycardia or certain cardiac conditions.
     • Calcium channel blockers: Can be effective but use with caution in certain renal conditions.
     • Diuretics (Thiazide or Loop): May be used if there is evidence of fluid overload or as adjunctive therapy.
   • Start Low and Titrate Slowly: Medications should be initiated at a low dose and gradually titrated based on blood pressure response and tolerability.
   • Regular Monitoring: Frequent blood pressure checks and monitoring for side effects are crucial.

3. Referral to a Pediatric Nephrologist or Pediatric Cardiologist: Given the high likelihood of secondary hypertension in this age group, early referral to a specialist experienced in managing hypertension in young children is essential for further evaluation, diagnosis, and management.

4. Treatment of the Underlying Cause: Addressing the primary medical condition (e.g., surgical correction of coarctation, management of renal disease, treatment of endocrine tumors) is the definitive treatment for secondary hypertension.

How would your plan of care be different if the child were 10 years old?

In a 10-year-old with newly diagnosed hypertension, the likelihood of essential (primary) hypertension increases, although secondary causes still need to be considered. The initial workup would be similar, but the emphasis on certain aspects might shift:

• History: Greater focus on lifestyle factors, including diet (sodium intake, processed foods), physical activity levels (screen time), and family history of essential hypertension and early cardiovascular disease.
• Physical Examination: Continue a thorough exam, but the focus on subtle signs of secondary causes might be less prominent initially, while still being vigilant. Assess for signs of target organ damage (e.g., fundoscopic exam).
• Laboratory Investigations: The initial panel would likely be the same, but the threshold for more specialized tests like renin-aldosterone levels or catecholamines might be higher unless there are specific clinical clues.
• Imaging Studies: Renal ultrasound would still be important, but other advanced imaging might be reserved for cases with specific indications.