What are the diagnostic criteria and treatment options for essential primary hypertension in adults?

Diagnostic Criteria for Essential Primary Hypertension

Essential (primary) hypertension is diagnosed when blood pressure is ≥130/80 mm Hg on repeated measurements after excluding secondary causes through history, physical examination, and basic laboratory testing. 1

Blood Pressure Thresholds for Diagnosis

• Hypertension is defined as systolic blood pressure (SBP) ≥130 mm Hg or diastolic blood pressure (DBP) ≥80 mm Hg based on the 2017 ACC/AHA guidelines 1, 2
• The older JNC 7 definition used ≥140/90 mm Hg, but the current standard lowers this threshold 1
• Diagnosis requires confirmation with multiple measurements over time, not a single elevated reading 1, 2
• Consider home blood pressure monitoring (HBPM) or ambulatory blood pressure monitoring (ABPM) to confirm diagnosis and exclude white-coat hypertension 1

Essential vs. Secondary Hypertension: The Critical Distinction

Essential hypertension is a diagnosis of exclusion—you must first rule out secondary causes, which account for approximately 10% of all hypertension cases. 1

When to Screen for Secondary Hypertension

Screen for secondary causes when any of these features are present 1:

• Resistant hypertension (uncontrolled BP on ≥3 medications including a diuretic) 1, 3
• Severe BP elevation (particularly sudden onset) 1
• Age <30 years with significant hypertension (though primary hypertension can occur in young adults, especially in Black patients) 1
• Sudden worsening of previously controlled hypertension 1
• Hypokalemia (spontaneous or disproportionate to diuretic use) 1, 3
• Target organ damage disproportionate to BP duration or severity 1
• Onset of diastolic hypertension in older adults 1
• Family history of early-onset hypertension or stroke at age <40 years 1, 3

Required Initial Evaluation for All Hypertensive Patients

Before diagnosing essential hypertension, perform 1:

History

• Medication review including NSAIDs, decongestants, oral contraceptives, stimulants, herbal products, and illicit drugs that can elevate BP 1
• Symptoms suggesting secondary causes: muscle weakness/cramps (primary aldosteronism), snoring/daytime sleepiness (obstructive sleep apnea), palpitations/headaches (pheochromocytoma) 1
• Family history of hypertension, early cardiovascular disease, or stroke 1
• Cardiovascular risk factors: diabetes, smoking, dyslipidemia 2

Physical Examination

• Blood pressure in both arms (difference >10 mm Hg suggests renovascular disease or coarctation) 1
• Abdominal auscultation for bruits (renovascular hypertension—critical and often missed) 1, 4
• Femoral pulses and BP in legs (coarctation of aorta, especially in young patients) 4
• Signs of Cushing syndrome: central obesity, facial plethora, wide purple striae, proximal muscle weakness 5
• Thyroid examination 5
• Cardiovascular examination for target organ damage 1

Laboratory Testing

• Serum creatinine with eGFR (renal parenchymal disease) 1, 5, 2
• Serum potassium (primary aldosteronism if low) 1, 3
• Fasting glucose or HbA1c (diabetes) 5, 2
• Lipid profile (cardiovascular risk assessment) 5, 2
• Urinalysis (proteinuria suggests renal disease) 2
• TSH (thyroid disease) 5
• ECG (left ventricular hypertrophy, prior MI) 2

Specific Screening for Primary Aldosteronism

Primary aldosteronism is the most common secondary cause, affecting up to 20% of patients with resistant hypertension, and is frequently missed. 1, 3

Mandatory Screening Indications (Class I Recommendation)

Screen with plasma aldosterone-to-renin ratio when 1, 3:

• Resistant hypertension 1, 3
• Hypokalemia (spontaneous or substantial if diuretic-induced) 1, 3
• Incidentally discovered adrenal mass 1, 3
• Family history of early-onset hypertension or stroke at age <40 years 1, 3

Critical Testing Preparation

• Correct hypokalemia before testing 1, 3
• Withdraw aldosterone antagonists for 4-6 weeks 1, 3
• Normal sodium diet before testing 3
• A positive screen requires both elevated aldosterone-to-renin ratio AND elevated absolute aldosterone level 3

Next Steps After Positive Screen

• Confirmatory testing with oral sodium loading test or IV saline infusion test 1, 3
• Mandatory referral to hypertension specialist or endocrinologist (Class I recommendation) 1, 3

Common Pitfalls to Avoid

• Missing medication-induced hypertension: Always review ALL medications, supplements, and substances before diagnosing essential hypertension 1
• Failing to auscultate the abdomen for bruits: This simple maneuver can detect renovascular hypertension 1, 4
• Assuming primary aldosteronism requires hypokalemia: Most patients with primary aldosteronism are normokalemic 1
• Diagnosing hypertension on a single measurement: Confirm with repeated measurements or out-of-office monitoring 1, 2
• Missing white-coat hypertension: Consider HBPM or ABPM, especially if target organ damage is absent despite elevated office readings 1

Final Diagnostic Algorithm

1. Confirm elevated BP (≥130/80 mm Hg) with repeated measurements 1, 2
2. Complete initial evaluation (history, physical, basic labs) to screen for secondary causes 1
3. If red flags present, pursue specific testing for secondary hypertension 1
4. If no secondary cause identified, diagnose essential hypertension 1, 6
5. Assess overall cardiovascular risk to guide treatment intensity 2