Essential Hypertension — Diagnosis and Management

• Neurohumoral dysregulation: Overactivity of the sympathetic nervous system increases peripheral vascular resistance through enhanced norepinephrine signaling at α1-adrenergic receptors on vascular smooth muscle. Simultaneously, the renin-angiotensin-aldosterone system (RAAS) is activated, with angiotensin II promoting vasoconstriction via AT1 receptors, increasing aldosterone-mediated sodium reabsorption, and amplifying sympathetic tone through central and peripheral mechanisms. Elevated intrarenal angiotensin II impairs pressure natriuresis, the critical renal mechanism for long-term blood pressure regulation.

• Endothelial dysfunction and vascular remodeling: Impaired endothelial production of nitric oxide (NO)—a potent vasodilator—reduces vasodilatory capacity and increases oxidative stress through enhanced superoxide production. This creates a vicious cycle of endothelial dysfunction, with increased production of vasoconstrictor prostanoids and reduced production of vasodilatory endothelium-derived hyperpolarizing factor (EDHF). Chronic blood pressure elevation triggers vascular smooth muscle cell proliferation and hypertrophic remodeling, increasing wall-to-lumen ratio and creating a structural basis for sustained elevated resistance.

• Sodium sensitivity and renal hemodynamic abnormalities: In approximately 50% of hypertensive patients (particularly African Americans and older adults), impaired renal sodium excretion leads to salt-sensitive hypertension, wherein dietary sodium directly elevates blood pressure. Reduced renal perfusion pressure from either primary renal disease or systemic hemodynamic changes triggers compensatory RAAS activation. Natriuretic peptides (ANP, BNP) are blunted in response to volume expansion, reducing their counterregulatory effects. Abnormalities in the epithelial sodium channel (ENaC) and Na-K-ATPase function contribute to impaired sodium handling, with recent evidence implicating dysregulation of the vascular endothelial glycocalyx in sodium accumulation.

• Genetic and epigenetic factors: Genome-wide association studies (GWAS) have identified >100 genetic loci associated with blood pressure regulation, though most individual variants confer modest effects. Genes regulating sodium transport (SLC12A3, NEDD4L), vascular tone (CYP11B2, CYP17A1), and endothelial function contribute to heritable risk. Epigenetic modifications, including DNA methylation and histone acetylation, alter expression of RAAS components and sodium transporters in response to environmental stressors.

• Inflammation and oxidative stress: Elevated circulating levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) promote endothelial inflammation and vascular stiffness. Increased reactive oxygen species (ROS), particularly from vascular NADPH oxidase activity, overwhelm antioxidant defenses and increase production of the vasoconstrictor endothelin-1, while simultaneously inactivating nitric oxide. Infiltration of macrophages and T lymphocytes into the vessel wall amplifies this inflammatory milieu.

• Arterial stiffness: Increased cross-linking of collagen and elastin in the tunica media, partly through advanced glycation end-products (AGEs), reduces arterial compliance. Elevated pulse pressure and reduced diastolic runoff further perpetuate systemic hypertension, particularly in older individuals and those with diabetes or chronic kidney disease.

Demographic and genetic factors

• Age: Blood pressure increases progressively with age; isolated systolic hypertension predominates after age 60 due to arterial stiffness
• Race/ethnicity: African Americans have higher prevalence (40–45%), more aggressive disease onset, and greater target organ damage compared to Caucasians; salt sensitivity is more common
• Sex: Males have higher prevalence before age 65; postmenopausal women approach male rates due to loss of estrogen's endothelial protective effects
• Family history: Hypertension in first-degree relatives increases risk; monozygotic twins show ~60% concordance

Environmental and behavioral factors

• Dietary sodium intake: Positive dose-response relationship; reduction of sodium intake by 2.3 g/day reduces blood pressure by 5.8/2.5 mmHg
• Obesity and metabolic syndrome: Each 1 kg/m² increase in BMI associates with ~0.4 mmHg increase in systolic blood pressure; visceral adiposity drives production of inflammatory cytokines and impairs adiponectin signaling
• Excessive alcohol consumption: >2 drinks/day in men or >1 drink/day in women increases blood pressure; J-shaped relationship with light consumption potentially protective
• Sedentary lifestyle: Physical inactivity associates with 20–30% increased hypertension risk; regular aerobic exercise reduces blood pressure 5–7 mmHg
• Psychological stress and depression: Chronic stress elevates catecholamines and cortisol; depression independently associates with hypertension and reduced treatment response
• Sleep disturbances and obstructive sleep apnea (OSA): Sleep deprivation impairs baroreceptor reflex sensitivity; OSA (apnea-hypopnea index ≥5) present in 40–80% of resistant hypertensive patients
• Dietary factors: High consumption of processed foods (elevated sodium, refined carbohydrates), low potassium intake, and low dietary fiber increase hypertension risk; DASH diet reduces blood pressure 11.4/5.5 mmHg

Comorbid conditions increasing hypertension risk

• Insulin resistance and diabetes mellitus: Hyperinsulinemia promotes renal sodium reabsorption and sympathetic activation; 80% of type 2 diabetics are hypertensive
• Chronic kidney disease: Reduced nephron number impairs pressure natriuresis; bidirectional relationship where hypertension causes CKD progression
• Dyslipidemia: Impaired endothelial function and increased oxidative stress
• Hyperuricemia: Uric acid decreases NO bioavailability and activates RAAS

Cardinal features

• Asymptomatic presentation (majority of cases): Essential hypertension is often discovered incidentally during routine physical examination or screening, with >50% of hypertensive individuals unaware of their diagnosis
• Absence of pathognomonic symptoms: Unlike secondary hypertension, which may present with specific symptom clusters, essential hypertension typically produces no specific symptoms attributable to elevated blood pressure alone
• Nonspecific symptoms when present: Mild headaches (temporal, occipital region), dizziness, epistaxis, and fatigue may occur, though these are no more common than in normotensive populations and should not be attributed to hypertension without excluding other etiologies; symptoms typically resolve despite persistent blood pressure elevation
• Symptoms of target organ damage (late manifestation): Dyspnea on exertion, orthopnea, or paroxysmal nocturnal dyspnea (indicating left ventricular dysfunction); anginal chest pain (from coronary ischemia); transient ischemic episodes or stroke prodrome

Physical examination findings

• Elevated blood pressure readings (diagnostic finding): Systolic ≥130 mmHg or diastolic ≥80 mmHg on ≥2 occasions; confirmation via out-of-office measurements (home or ambulatory) is critical before initiating therapy to exclude white-coat hypertension
• Left ventricular hypertrophy (LVH) signs: Sustained apical impulse displaced laterally and inferiorly (>5 cm from midclavicular line), sustained and sustained forceful impulse; paradoxical splitting of S2; S4 gallop from reduced ventricular compliance; diastolic murmur of aortic regurgitation (from LV dilatation)
• Retinal findings (Keith-Wagener-Barker classification): Grade I, mild arteriolar narrowing; Grade II, focal arteriolar narrowing ("beading"), arteriovenous nicking; Grade III, microinfarcts (cotton-wool spots), hard exudates, retinal hemorrhages; Grade IV, papilledema (hypertensive emergency)
• Other vascular findings: Reduced peripheral pulses, femoral bruits (suggestive of aortic atherosclerosis or coarctation), diminished carotid upstrokes
• Stigmata of secondary hypertension or end-organ damage: Cushingoid habitus, hirsutism (adrenal disease); tremor, tachycardia, heat intolerance (hyperthyroidism); abdominal mass or bruit (renal artery stenosis); diminished pulses in legs (aortic coarctation); neurofibromatosis café-au-lait spots (pheochromocytoma association)

Clinical diagnostic approach

• Blood pressure measurement technique (foundational to accurate diagnosis):
• Office/clinic measurement (gold standard for diagnosis): Patient seated with feet flat on floor, back supported, arm at heart level; measurement after 5 minutes of quiet rest; average of ≥2 readings obtained ≥1–2 minutes apart
• Home blood pressure monitoring (HBPM): Patient or caregiver measures blood pressure using validated automated oscillometric device in relaxed state, morning and evening for ≥5 days (ideally 7 days); values averaged; more predictive of cardiovascular outcomes than office readings; diagnostic threshold ≥135/85 mmHg (lower than office due to absence of white-coat effect)
• Ambulatory blood pressure monitoring (ABPM): 24-hour continuous monitoring using portable device; provides wake, sleep, and 24-hour average readings; identifies diurnal blood pressure pattern (normal "dippers" with ≥10% nocturnal decline vs. "non-dippers" with <10% decline, associated with worse prognosis); daytime threshold ≥135/85 mmHg, nighttime ≥120/70 mmHg, 24-hour ≥130/80 mmHg; indicated when office readings discordant with symptom burden or in suspected white-coat (elevated office, normal ABPM) or masked (normal office, elevated ABPM) hypertension

• Diagnostic classification (2017 ACC/AHA Hypertension Guidelines):
• Normal blood pressure: <120/<80 mmHg
• Elevated: Systolic 120–129 AND diastolic <80 mmHg (no pharmacotherapy; lifestyle modification emphasized)
• Stage 1 hypertension: Systolic 130–139 OR diastolic 80–89 mmHg
• Stage 2 hypertension: Systolic ≥140 OR diastolic ≥90 mmHg
• Note: 2016 ESC/ESH guidelines use slightly different thresholds (≥140/90 mmHg for Stage 1); ACC/AHA classification captures more individuals for intervention based on cardiovascular risk reduction data

• Comprehensive metabolic and laboratory evaluation (establish baseline and identify secondary causes):
• Electrolytes and renal function: Serum sodium, potassium (hypokalemia suggests aldosteronism or diuretic use), blood urea nitrogen (BUN), creatinine, and estimated glomerular filtration rate (eGFR) [normal eGFR >60 mL/min/1.73 m²]; baseline assessment critical as ACE inhibitors and ARBs can elevate potassium and creatinine
• Fasting glucose and HbA1c: Screen for diabetes (fasting glucose ≥126 mg/dL or HbA1c ≥6.5%); insulin resistance contributes to hypertension pathogenesis
• Lipid panel: Total, LDL, and HDL cholesterol and triglycerides; dyslipidemia commonly coexists and modifies cardiovascular risk
• Urinalysis: Screen for hematuria (renal disease), proteinuria (glomerulonephritis, diabetic nephropathy), or casts (active glomerulonephritis)
• Urine albumin-to-creatinine ratio (UACR): Quantifies albuminuria; UACR >30 mg/g indicates microalbuminuria (early marker of hypertensive nephropathy); >300 mg/g indicates overt proteinuria
• 24-hour urine sodium and potassium (optional): Can guide dietary modification targets; high-sodium excretioners more responsive to salt restriction

• Selective testing to exclude secondary hypertension (indicated in ~10% of hypertensive patients):
• Primary aldosteronism screening: Plasma aldosterone-to-renin activity ratio (ARR) >20–30 (units depend on assay); if elevated, confirmatory testing with saline suppression test or captopril challenge test; adrenal CT/MRI if positive (aldosterone-producing adenoma in 30–40% of cases, bilateral hyperplasia in 60–70%)
• Renovascular hypertension: Captopril renal scintigraphy (older, less sensitive); CT or MR angiography (preferred); renal duplex ultrasound (operator-dependent); renal artery stenosis present in 1–5% of general hypertensive population, up to 10–15% in patients with resistant hypertension
• Pheochromocytoma: 24-hour urine metanephrines and catecholamines or plasma free metanephrines (>150% of upper limit normal suggests pheochromocytoma); CT/MRI adrenal imaging if biochemical testing positive; MIBG scintigraphy for extra-adrenal tumors
• Hyperthyroidism: Thyroid-stimulating hormone (TSH) and free T4; patient history of heat intolerance, weight loss, or tremor
• Cushing syndrome: 24-hour urine-free cortisol or dexamethasone suppression test if clinical suspicion (central obesity, purple striae, hirsutism)
• Obstructive sleep apnea: STOP-BANG questionnaire (8-item screening tool); polysomnography or portable sleep apnea testing if high pretest probability

• Cardiovascular risk stratification and target organ damage assessment:
• Electrocardiography (ECG): Assess for left ventricular hypertrophy (LVH) using Sokolow-Lyon criteria (RV1 + SV5 >3.5 mV) or Cornell criteria (most sensitive); Q waves, ST changes (ischemia), or arrhythmias; though ECG has limited sensitivity (~50%), presence of LVH on ECG strongly predicts adverse outcomes
• Transthoracic echocardiography: Gold standard for LVH diagnosis and quantification; measures left ventricular mass index (LVMI; normal <115 g/m² in men, <95 g/m² in women); assesses systolic and diastolic function; identifies concentric (increased relative wall thickness, preserved cavity size) versus eccentric (cavity dilat

• IV vasodilators/beta blockade: nicardipine, clevidipine, or labetalol; sodium nitroprusside is a second-line option because thiocyanate/cyanide accumulates in renal impairment.
• Rate of lowering: reduce mean arterial pressure by roughly a quarter in the first hour, then gradually over 24–48 hours — autoregulatory curves are right-shifted in chronic hypertension, so abrupt normalisation causes watershed cerebral, retinal, and renal ischemia.
• Exceptions: aortic dissection requires rapid reduction of systolic pressure and heart rate, with beta blockade (esmolol) given before any vasodilator to prevent reflex tachycardia and increased aortic wall shear stress.
• Severe asymptomatic hypertension ("urgency") has no end-organ injury: restart/uptitrate oral agents and arrange close follow-up — not IV therapy.

• Thiazide-type diuretic: chlorthalidone (longer acting, more outcome data than hydrochlorothiazide).
• ACE inhibitor or ARB: lisinopril or losartan — preferred with albuminuric CKD (KDIGO) or diabetic kidney disease (ADA Standards of Care).
• Dihydropyridine calcium channel blocker: amlodipine.
• Black adults without HF or CKD: begin with a thiazide or CCB.
• Stage 2 warrants two agents of different classes, ideally as a single-pill combination.

Cardiac

• Left ventricular hypertrophy → HFpEF: chronic pressure overload causes concentric hypertrophy and impaired relaxation; signalled by an S4 gallop, sustained laterally displaced apical impulse, and increased LV mass index on echocardiography.
• Coronary disease and myocardial infarction: accelerated atherosclerosis plus increased wall stress raises oxygen demand while hypertrophy compresses subendocardial perfusion.
• Atrial fibrillation: elevated LA pressure from diastolic dysfunction produces atrial stretch and fibrosis; presents as palpitations or embolic stroke.

Cerebrovascular

• Ischemic stroke and lacunar infarcts: lipohyalinosis of penetrating lenticulostriate arteries; pure motor or pure sensory deficits.
• Intracerebral hemorrhage (emergency): rupture of Charcot–Bouchard microaneurysms, classically basal ganglia/thalamus; sudden deficit with headache and vomiting.
• Hypertensive encephalopathy / PRES (emergency): breakthrough of cerebral autoregulation with vasogenic edema; headache, confusion, seizures, posterior white-matter edema on MRI.

Renal

• Hypertensive nephrosclerosis: hyaline arteriolosclerosis narrows afferent arterioles; albuminuria and slowly falling eGFR.
• Malignant nephrosclerosis (emergency): fibrinoid necrosis with hyperplastic "onion-skin" arteriolosclerosis; acute kidney injury, hematuria, and thrombotic microangiopathy with schistocytes and thrombocytopenia.

Vascular and ocular

• Aortic dissection and aneurysm (emergency): tearing interscapular pain, pulse/BP differential, widened mediastinum.
• Hypertensive retinopathy: arteriovenous nicking and cotton-wool spots; papilledema defines emergency.

Treatment-related

• Thiazides: hypokalemia, hyponatremia, hyperuricemia precipitating gout, hypercalcemia, hyperglycemia.
• ACE inhibitors: bradykinin-mediated dry cough and angioedema; hyperkalemia; a creatinine rise beyond the expected small bump suggests bilateral renal artery stenosis; fetal renal maldevelopment and oligohydramnios.
• Dihydropyridine CCBs: precapillary arteriolar dilation causes dose-dependent ankle edema (diuretics do not fix it); gingival hyperplasia, reflex tachycardia.
• Spironolactone: hyperkalemia and gynecomastia.
• Beta blockers: bradycardia, fatigue, masking of hypoglycemic warning signs; abrupt withdrawal causes rebound ischemia.
• Hydralazine: drug-induced lupus; clonidine: rebound hypertension; nitroprusside: cyanide toxicity.
• Over-rapid pressure reduction (emergency): watershed infarction, ischemic optic neuropathy, oliguria.

• Confirm before you commit: an elevated office reading alone does not diagnose hypertension. The single best next step in a well patient with one high reading is repeat measurement plus home or ambulatory monitoring to exclude white-coat hypertension — and to catch masked hypertension, which carries the same risk as sustained disease.
• Severe asymptomatic hypertension is not an emergency: the classic distractor is IV labetalol or nitroprusside for a patient with markedly elevated pressure but no end-organ injury. Correct answer is oral therapy and outpatient follow-up; rapid lowering causes watershed infarction.
• Emergency is defined by the organ, not the number: papilledema, encephalopathy, dissection, pulmonary edema, or acute kidney injury with schistocytes moves the patient to IV titratable therapy in the ICU (2017 ACC/AHA).
• Aortic dissection reverses the usual order: give a beta blocker before the vasodilator — unopposed vasodilation causes reflex tachycardia and increased dP/dt, propagating the tear.
• Hypertension plus unprovoked hypokalemia is the association examiners love: screen for primary aldosteronism with the plasma aldosterone-to-renin ratio, not with imaging first.
• Match the drug to the comorbidity: albuminuric CKD or diabetic kidney disease → ACE inhibitor or ARB (KDIGO, ADA); Black adults without CKD or heart failure → thiazide or dihydropyridine CCB first (ACC/AHA); HFrEF requires all four classes — ARNI (or ACEI/ARB), beta blocker, MRA, and SGLT2 inhibitor.
• Resistant hypertension on three drugs including a diuretic → add spironolactone, after confirming adherence and screening for OSA and aldosteronism.
• Side-effect fingerprints: dry cough → ACE inhibitor (switch to ARB); ankle edema unresponsive to diuretics → amlodipine; gynecomastia → spironolactone; drug-induced lupus → hydralazine.
• Pregnancy: labetalol, nifedipine, or methyldopa (ACOG). Every ACE inhibitor and ARB is contraindicated — captopril's short half-life makes it handy for rapid titration in non-pregnant patients only.