Causes of Hypertension in Young Individuals
In young patients with hypertension, primary (essential) hypertension is now the predominant diagnosis, particularly in those ≥6 years with obesity and positive family history, though secondary causes remain important to identify—especially renal disease, primary aldosteronism, and renovascular disease. 1
Primary vs. Secondary Hypertension Framework
The approach differs significantly based on age and clinical presentation:
Primary Hypertension (Most Common in Older Children/Adolescents)
Children and adolescents ≥6 years do NOT require extensive evaluation for secondary causes if they have:
- Positive family history of hypertension
- Overweight or obesity (BMI ≥85th percentile)
- No concerning history or physical examination findings 1
Primary hypertension is now the predominant diagnosis in referral centers, with obesity being the strongest correlate—showing a fourfold increase in hypertension risk with severe obesity (BMI >99th percentile) versus twofold with standard obesity 1
Secondary Hypertension (Requires Investigation)
Recent research shows secondary hypertension prevalence ranges from 29.6% to 33% in young adults under 40 years 2, 3, which is substantially higher than previously recognized.
Most Common Secondary Causes (In Order of Frequency)
1. Renal and Renovascular Disease (Most Common Overall)
- Renal parenchymal disease and structural abnormalities: 34-79% of secondary cases 1
- Renovascular disease: 12-13% of secondary cases 1
- In young adults specifically, renal disease accounts for approximately 12.9% of secondary hypertension 2
- Key predictor: Elevated creatinine (OR 1.03 per 1 mmol/L increase) 4
2. Primary Aldosteronism
- Most frequent endocrine cause: 54.8% of secondary hypertension cases in young adults 2
- Accounts for 11.5% overall in young hypertensive populations 3
- Key clinical clue: Hypokalemia (OR 3.69 for secondary HTN) 5
3. Sleep Apnea/Obstructive Sleep Apnea Syndrome (OSAS)
- Second most common after renal disease in some cohorts 4
- Use ABPM to evaluate for potential hypertension in children/adolescents with known or suspected OSAS 1
4. Renovascular Hypertension (Fibromuscular Dysplasia)
- 18.4% of secondary cases in young adults 2
- 5.4% overall prevalence 3
- Suspect when: Stage 2 HTN, significant diastolic HTN, discrepant kidney sizes on ultrasound, hypokalemia, or epigastric/upper abdominal bruit 1
5. Medication/Drug-Related
- Prescription medications: Oral contraceptives (involved in 19% of young hypertensive women), CNS stimulants, corticosteroids 1, 3
- Over-the-counter: Decongestants (pseudoephedrine, phenylpropanolamine), NSAIDs 1
- Recreational drugs: Cocaine, amphetamine derivatives, anabolic steroids 1
- Supplements: Ephedra (ma huang) containing ephedrine and caffeine 1
6. Cardiac Causes
- Coarctation of the aorta: Right arm BP ≥20 mm Hg greater than lower extremity BP 1
- Post-coarctation repair patients should undergo ABPM for detection of hypertension including masked hypertension 1
7. Pheochromocytoma/Paraganglioma
- 5.9% of secondary cases 2
8. Monogenic Hypertension (Rare)
- Confirmed in 3% of select hypertensive children without known etiology 1
- Includes: Liddle syndrome, Gordon syndrome, apparent mineralocorticoid excess, familial glucocorticoid resistance, congenital adrenal hyperplasia
- All manifest with: Suppressed plasma renin activity, increased distal tubule sodium absorption, ± potassium abnormalities, ± metabolic acid-base disturbances 1
Clinical Predictors of Secondary Hypertension
Three key predictors significantly increase likelihood:
- Female sex (OR 4.56) 5
- Systolic BP >160 mm Hg at diagnosis (OR 1.44) 5
- Serum potassium <3.5 mEq/L (OR 3.69) 5
Additional risk factors:
- Treatment with ≥2 medications 2
- No family history of hypertension 2
- BMI <25 kg/m² (paradoxically suggests secondary cause) 2
- Diabetes mellitus (OR 2.79) 4
Important Clinical Pitfalls
Age matters but not as much as previously thought: The prevalence of secondary hypertension is higher in the 30-40 year age group than 18-30 years (P=0.024), but patients with BP <160/100 mm Hg did NOT have lower prevalence of secondary hypertension regardless of number of treatments 2. This challenges the assumption that mild hypertension in young adults is always primary.
Extensive universal screening may be unnecessary: Apart from renal disease and sleep apnea, other forms of secondary hypertension are extremely rare 4. However, all patients with hypertension under 40 years should be screened for secondary causes given the 29.6% prevalence 2.
Essential Historical Elements to Obtain
Perinatal History
- Maternal hypertension during pregnancy
- Low birth weight
- Preterm birth
- Gestational age and complications
- Umbilical catheter placement 1
Nutritional History
- High sodium intake (twofold increase in HTN risk; threefold with obesity) 1
- High total fat and saturated fat consumption
- Sugary beverage consumption
- Processed and fast food intake
Medication/Substance History
- All prescription medications (especially oral contraceptives, stimulants, corticosteroids)
- Over-the-counter cold medications
- Herbal/nutritional supplements
- Recreational drug use (cocaine, amphetamines, anabolic steroids) 1
Psychosocial History
- Adverse childhood experiences (associated with adult-onset HTN)
- Depression and anxiety (may suggest white coat hypertension)
- Smoking, alcohol, drug use (starting at age 11) 1