Definition
Essential Hypertension is characterised by persistently elevated blood pressure (BP) without a known secondary cause. It is the most prevalent type of hypertension, contributing significantly to cardiovascular and renal morbidity and mortality.
Key Diagnostic Criteria
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American College of Cardiology (ACC)/American Heart Association (AHA) 2017 Guidelines:
- Normal BP: Systolic <120 mmHg and diastolic <80 mmHg.
- Elevated BP: Systolic 120–129 mmHg and diastolic <80 mmHg.
- Hypertension Stage 1: Systolic 130–139 mmHg or diastolic 80–89 mmHg.
- Hypertension Stage 2: Systolic ≥140 mmHg or diastolic ≥90 mmHg.
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European Society of Cardiology (ESC)/European Society of Hypertension (ESH):
- Hypertension is defined as:
- Office BP: Systolic ≥140 mmHg and/or diastolic ≥90 mmHg.
- 24-hour Ambulatory BP: Systolic ≥130 mmHg or diastolic ≥80 mmHg.
- Daytime BP: Systolic ≥135 mmHg or diastolic ≥85 mmHg.
- Nighttime BP: Systolic ≥120 mmHg or diastolic ≥70 mmHg.
- Hypertension is defined as:
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World Health Organization (WHO):
- Diagnosis of hypertension begins at a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, with pharmacologic treatment initiated after confirmation.
- Diagnosis of hypertension begins at a systolic BP ≥140 mmHg or diastolic BP ≥90 mmHg, with pharmacologic treatment initiated after confirmation.
Specific Subtypes
- Isolated Systolic Hypertension: Systolic BP ≥130 mmHg and diastolic <80 mmHg.
- Isolated Diastolic Hypertension: Systolic BP <130 mmHg and diastolic ≥80 mmHg.
Diagnostic Approach
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Measurement Techniques:
- Use standardised office measurements.
- Confirm with out-of-office monitoring methods like Ambulatory Blood Pressure Monitoring (ABPM) or Home Blood Pressure Monitoring (HBPM).
- ABPM is preferred for identifying conditions like white-coat hypertension and masked hypertension.
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Criteria for Hypertension Using ABPM/HBPM:
- 24-hour Mean BP: Systolic ≥125 mmHg or diastolic ≥75 mmHg.
- Daytime Mean BP: Systolic ≥130 mmHg or diastolic ≥80 mmHg.
- Nighttime Mean BP: Systolic ≥110 mmHg or diastolic ≥65 mmHg.
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Confirmatory Requirements:
- Repeat measurements on two or more separate occasions are needed for diagnosis.
- Utilise ABPM or HBPM to confirm persistent elevation.
Associated Guidelines for Blood Pressure Goals
- ACC/AHA: Target <130/80 mmHg for all adults with confirmed hypertension.
- ESC/ESH: Initial target <140/90 mmHg, with further reduction to <130/80 mmHg if tolerated.
- WHO: Aim for <140/90 mmHg universally, with stricter targets for patients with comorbidities like diabetes or chronic kidney disease.
Aetiology
Primary Hypertension
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Disruption of Auto-Regulation
- Reflex mechanisms that normally balance vascular resistance and cardiac output fail, leading to persistent increases in blood pressure.
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Dietary Sodium Intake
- High sodium intake elevates blood pressure via fluid retention and vascular changes. Sodium sensitivity varies among individuals.
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Renal Sodium Retention
- Impaired renal sodium excretion increases extracellular fluid volume, driving hypertension.
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Renin-Angiotensin-Aldosterone System (RAAS) Dysregulation
- Elevated plasma renin activity promotes sodium retention and vasoconstriction, amplifying hypertension.
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Increased Sympathetic Nervous System Activity
- Chronic activation elevates cardiac output and peripheral resistance, contributing to sustained hypertension.
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Endothelial Dysfunction
- Reduced nitric oxide bioavailability and increased oxidative stress impair vasodilation.
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Cell Membrane Transporter Abnormalities
- Altered ion transport mechanisms affect vascular tone and responsiveness.
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Insulin Resistance and Hyperinsulinaemia
- These states promote sodium retention, sympathetic activation, and vascular dysfunction.
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Genetic Predisposition
- Studies suggest heritability accounts for 33–57% of blood pressure variability. Genome-wide association studies have identified loci linked to hypertension.
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Epigenetics
- Environmental exposures, such as stress or a high-salt diet, can induce epigenetic modifications that influence blood pressure regulation.
- Environmental exposures, such as stress or a high-salt diet, can induce epigenetic modifications that influence blood pressure regulation.
Environmental and Lifestyle Contributors
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Obesity
- Increased adiposity raises blood pressure through insulin resistance, sympathetic activation, and hormonal changes.
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Dietary Patterns
- High-sodium, low-potassium diets exacerbate hypertension risk.
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Physical Inactivity
- Sedentary behavior is associated with reduced vascular compliance and increased peripheral resistance.
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Alcohol Consumption
- Excessive alcohol intake increases blood pressure in a dose-dependent manner.
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Psychosocial Stress and Sleep Deprivation
- Chronic stress and insufficient sleep disrupt autonomic regulation of blood pressure.
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Environmental Factors
- Exposure to air pollution and noise has been linked to higher blood pressure.
- Exposure to air pollution and noise has been linked to higher blood pressure.
Pathophysiology
Key Mechanisms in the Pathogenesis of Hypertension
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Blood Pressure Regulation
- Formula: BP = CO × SVR.
- BP changes dynamically to maintain organ perfusion. The primary regulators include:
- Sympathetic Nervous System (SNS): Enhances cardiac output and vasoconstriction.
- Renin-Angiotensin-Aldosterone System (RAAS): Promotes sodium retention, water reabsorption, and vascular constriction.
- Kidneys: Regulate plasma volume and sodium excretion.
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Structural and Functional Vascular Changes
- Remodeling and hypertrophy of resistance arterioles increase SVR.
- Endothelial dysfunction, characterised by reduced nitric oxide bioavailability, promotes vasoconstriction and oxidative stress.
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Sodium Handling and Volume Expansion
- Excessive sodium intake and renal sodium retention expand intravascular volume, increasing CO and BP.
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Neurohormonal Dysregulation
- Overactivation of the SNS contributes to increased vascular tone and cardiac stimulation.
- Dysregulated RAAS amplifies sodium retention and vasoconstriction.
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Immune System Activation
- Emerging evidence implicates immune cells, particularly T-lymphocytes, in hypertension:
- Lipid oxidation products act as neoantigens, activating T-cells that infiltrate vascular and renal tissues.
- Cytokines such as interleukin-17 and tumor necrosis factor-alpha exacerbate vascular inflammation.
- Emerging evidence implicates immune cells, particularly T-lymphocytes, in hypertension:
Natural History and Progression
Hypertension progresses through distinct stages, each characterised by specific hemodynamic changes and clinical manifestations:
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Prehypertension (Ages 10–30 Years):
- Elevated CO with normal SVR due to increased blood volume and adrenergic activity.
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Early Hypertension (Ages 20–40 Years):
- Peripheral resistance rises due to vascular remodeling and sustained SNS activity.
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Established Hypertension (Ages 30–50 Years):
- Vascular resistance becomes the dominant factor as cardiac output normalises or slightly decreases.
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Complicated Hypertension (Ages 40–60 Years):
- Chronic hypertension results in end-organ damage, including atherosclerosis, left ventricular hypertrophy, renal dysfunction, and cerebrovascular changes.
- Chronic hypertension results in end-organ damage, including atherosclerosis, left ventricular hypertrophy, renal dysfunction, and cerebrovascular changes.
Contributing Factors and Novel Insights
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Oxidative Stress and Endothelial Injury
- Persistent oxidative stress damages vascular endothelium, leading to thrombotic and inflammatory cascades that perpetuate hypertension.
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Role of the Microbiome
- Altered gut microbiota has been implicated in immune dysregulation and increased BP, though mechanisms remain under investigation.
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Cortisol Reactivity and Stress
- Increased hypothalamic-pituitary-adrenal (HPA) axis activity under chronic stress elevates BP through sustained cortisol secretion.
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Systemic Inflammation
- Hypertension is associated with chronic low-grade inflammation, mediated by immune cells and inflammatory cytokines.
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Genetic and Epigenetic Influences
- Genetic predisposition contributes to susceptibility, while environmental factors (e.g., diet, stress) drive epigenetic modifications that influence RAAS, SNS, and vascular function.
- Genetic predisposition contributes to susceptibility, while environmental factors (e.g., diet, stress) drive epigenetic modifications that influence RAAS, SNS, and vascular function.
End-Organ Damage
Chronic hypertension leads to structural and functional changes across multiple organ systems:
- Cardiovascular: Left ventricular hypertrophy, atherosclerosis, and heart failure.
- Renal: Nephrosclerosis and chronic kidney disease.
- Neurological: Increased risk of stroke, vascular dementia, and hypertensive encephalopathy.
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Ophthalmic: Hypertensive retinopathy.
Research
- Studies have demonstrated the critical role of systolic BP in predicting cardiovascular complications. Systolic BP rises progressively with age, whereas diastolic BP stabilises or declines after midlife.
- Immune modulation therapies and microbiome-targeted interventions are being explored as potential treatments for resistant hypertension.
Epidemiology
Global Prevalence
- Over 1 billion adults globally have hypertension, affecting approximately 26% of the world’s population, with projections estimating an increase to 29% (1.5 billion individuals) by 2025.
- The prevalence rises with age, affecting 60% of individuals aged 60 years or older.
- Hypertension is the leading modifiable risk factor for cardiovascular diseases, accounting for substantial disability-adjusted life years (DALYs) and mortality worldwide.
Regional Variations
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High-Income Countries
- Declines in prevalence have been noted due to increased awareness, better treatment, and effective blood pressure control programs.
- Less than 25% of hypertensive individuals have adequate blood pressure control (BP <140/90 mmHg).
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Low- and Middle-Income Countries
- Rising rates of hypertension are driven by urbanisation, dietary changes, and reduced physical activity.
- Hypertension management remains inadequate, with most affected individuals untreated or poorly controlled.
United States Epidemiology
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National Health and Nutrition Examination Surveys (NHANES):
- 46.7% of adults aged ≥20 years have hypertension, equating to over 122.4 million individuals.
- Prevalence by age groups:
- 20–44 years: 28.5%
- 45–64 years: 58.6%
- ≥65 years: 76.5%
- Control rates declined from 54.1% (2013–2014) to 48.3% (2017–2020), with a slight improvement to 51.1% by 2023.
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Sex and Ethnicity:
- Men have a higher prevalence of hypertension than women before 65 years of age, reversing in older age groups.
- Non-Hispanic Black populations exhibit the highest prevalence, associated with increased rates of end-stage renal disease (ESRD), stroke, and cardiovascular mortality.
United Kingdom
- In England, hypertension affects 31% of men and 26% of women, with over 25% of the adult population diagnosed with high blood pressure.
Key Risk Factors and Trends
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Age and Sex:
- Prevalence increases with age.
- Females have lower rates until the fifth decade, after which their rates exceed those of males.
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Ethnicity:
- Hypertension is more common and severe among Black individuals, with higher rates of associated complications.
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Lifestyle Factors:
- Sedentary behavior, high sodium intake, and obesity contribute significantly to hypertension prevalence.
- Sedentary behavior, high sodium intake, and obesity contribute significantly to hypertension prevalence.
Future Trends
- The global burden of hypertension is expected to rise, particularly in developing nations, unless substantial interventions are implemented to address its primary risk factors and improve treatment accessibility.
History
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Confirmation of Hypertension Diagnosis
- Elevated BP confirmed by multiple readings on at least three separate occasions.
- Documentation of the average BP from two or more readings during each visit.
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Duration and Course of Hypertension
- Onset and progression of BP readings.
- Last known normal BP and history of previous measurements.
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Assessment of End-Organ Damage
- Cardiac: Left ventricular hypertrophy, heart failure, angina, or history of myocardial infarction.
- Neurological: Stroke, transient ischemic attack, or cognitive decline.
- Renal: Chronic kidney disease or reduced estimated glomerular filtration rate (eGFR).
- Ophthalmic: Hypertensive retinopathy.
- Peripheral Arterial Disease: Claudication or reduced peripheral pulses.
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Cardiovascular Risk Factors
- Smoking, dyslipidemia, diabetes mellitus, obesity (BMI ≥30 kg/m²), and sedentary lifestyle.
- Microalbuminuria and elevated LDL cholesterol or low HDL cholesterol.
- Family history of premature cardiovascular disease (men <55 years, women <65 years).
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Potential Secondary Causes of Hypertension
- Renal diseases (e.g., chronic kidney disease, renovascular hypertension).
- Endocrine disorders (e.g., primary aldosteronism, pheochromocytoma, Cushing syndrome, hyperthyroidism, or hypothyroidism).
- Obstructive sleep apnea (OSA).
- Drug-induced hypertension (e.g., oral contraceptives, NSAIDs, corticosteroids, sympathomimetics, or illicit drugs such as cocaine).
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Lifestyle and Dietary Factors
- Dietary History: High sodium intake, processed foods, and low fruit and vegetable consumption.
- Physical Activity: Aerobic exercise frequency and intensity.
- Alcohol Consumption: Chronic intake exceeding 1 drink/day for women and 2 drinks/day for men.
- Psychosocial Stressors: Work status, educational level, and family structure.
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History of Medication Use
- Current and prior antihypertensive treatments: effectiveness, side effects, and adherence.
- Over-the-counter medications and supplements: NSAIDs, decongestants, herbal products (e.g., licorice root).
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Symptoms Suggesting Secondary Hypertension
- Palpitations, sweating, and labile hypertension (pheochromocytoma).
- Flank pain (renal causes).
- Muscle weakness (hyperaldosteronism).
- Daytime somnolence, loud snoring, and morning headaches (OSA).
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Symptoms of Target-Organ Damage
- Neurological: Headaches, transient blindness, or motor/sensory deficits.
- Cardiac: Chest pain or dyspnea.
- Renal: Reduced urinary output or hematuria.
- Ophthalmic: Visual disturbances, floaters, or papilledema.
Risk Factors and Strong Associations
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Age and Sex
- Incidence increases with age.
- Hypertension is more common in men before age 65 and in women after 65.
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Ethnicity
- Highest prevalence in Black individuals, who experience earlier onset, more severe hypertension, and greater risk of complications.
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Obesity
- A strong association exists between abdominal obesity and hypertension due to increased circulating volume and vascular resistance.
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Alcohol and Smoking
- Chronic alcohol intake raises BP in a dose-dependent manner.
- Smoking acutely raises BP and exacerbates cardiovascular risk.
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Comorbidities
- Diabetes mellitus and metabolic syndrome are frequently associated with hypertension and increase cardiovascular morbidity.
Physical Examination
Blood Pressure (BP) Measurement
- Ensure accuracy by:
- Using a validated device and an appropriately sized cuff, particularly for larger arm circumferences (>30 cm).
- Measuring BP in both arms and one leg on the first visit to detect conditions such as coarctation of the aorta or subclavian artery stenosis.
- Repeating measurements at 1–2 minute intervals during the visit and averaging at least two readings.
- Evaluate for "nondipping" BP patterns using ambulatory BP monitoring, which is associated with increased cardiovascular risk.
General Inspection
- General Appearance: Assess for obesity, central fat distribution, or signs of metabolic syndrome.
- Skin: Look for features of hypercortisolism (thin skin, easy bruising) or secondary hypertension causes.
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Alertness: Note confusion or altered mental status, which may indicate hypertensive encephalopathy.
Cardiac Examination
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Heart Sounds:
- Fourth heart sound (S4): Suggests left ventricular hypertrophy or diastolic dysfunction.
- Systolic ejection murmur: May indicate aortic valve disease.
- Tambour second sound (S2): Associated with aortic root dilatation.
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Apical Impulse:
- Displacement and enlargement suggest left ventricular hypertrophy.
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Peripheral Oedema and Rales:
- Indicative of cardiac dysfunction and chronic hypertension.
- Indicative of cardiac dysfunction and chronic hypertension.
Vascular Examination
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Coarctation of the Aorta:
- Look for radio-radial or radio-femoral pulse delay and a >20 mmHg BP difference between the arms or between upper and lower limbs.
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Bruits:
- Carotid or abdominal bruits may indicate renovascular hypertension or fibromuscular dysplasia (FMD).
- Carotid or abdominal bruits may indicate renovascular hypertension or fibromuscular dysplasia (FMD).
Abdominal Examination
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Palpation:
- Detect renal masses, as in polycystic kidney disease.
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Auscultation:
- Renal artery bruits with systolic and diastolic components suggest renovascular disease.
- Renal artery bruits with systolic and diastolic components suggest renovascular disease.
Funduscopic Examination
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Hypertensive Retinopathy:
- Retinal changes include:
- Hemorrhages, cotton-wool spots, and hard exudates.
- Arteriolar narrowing, arteriovenous nicking, or copper/silver wiring.
- Papilledema in severe or malignant hypertension.
- Retinopathy is associated with higher risks of stroke and cardiovascular events.
- Retinal changes include:
Endocrine Assessment
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Thyroid Gland:
- Palpate for enlargement or nodules, suggestive of hypothyroidism or hyperthyroidism.
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Adrenal Function:
- Symptoms like muscle weakness and hyperpigmentation may indicate hyperaldosteronism or Cushing syndrome.
- Symptoms like muscle weakness and hyperpigmentation may indicate hyperaldosteronism or Cushing syndrome.
Neurological Examination
- Look for:
- Visual disturbances (e.g., transient blindness or papilledema).
- Focal neurological deficits, which may indicate stroke or transient ischemic attack.
Signs Suggesting Secondary Hypertension
- Renovascular Hypertension: Abdominal bruit, especially with both systolic and diastolic components.
- Endocrine Disorders: Features such as hyperglycemia, truncal obesity, or abnormal skin findings.
- Obstructive Sleep Apnea (OSA): Daytime somnolence, loud snoring, and morning headaches.
Investigations
Blood Pressure (BP) Measurement:
- Measure BP in both arms.
- If inter-arm difference >15 mmHg, repeat measurements and use the higher reading arm for subsequent assessments.
Clinic BP:
- If BP is ≥140/90 mmHg:
- Take a second reading; if substantially different, take a third.
- Record the lower of the last two measurements as the clinic BP.
Ambulatory/Home BP Monitoring:
- For clinic BP between 140/90 mmHg and 180/120 mmHg, confirm with:
- Ambulatory BP Monitoring (ABPM): Average at least 14 readings taken during usual waking hours.
- Home BP Monitoring (HBPM): Record twice daily for at least 4 days (preferably 7); average the readings excluding the first day.
Confirmation Criteria:
- Hypertension is confirmed with:
- Clinic BP ≥140/90 mmHg and
- ABPM daytime average or HBPM average ≥135/85 mmHg.
Further Steps While Awaiting Confirmation:
- Assess for target organ damage and evaluate cardiovascular risk using appropriate tools.
Initial Investigations
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Urinary Albumin-to-Creatinine Ratio (UACR)
- Detects microalbuminuria, an early marker of chronic kidney disease (CKD) and end-organ damage.
- Recommended for all newly diagnosed hypertensive patients.
- For moderate-to-severe CKD, repeat UACR, serum creatinine, and estimated glomerular filtration rate (eGFR) annually.
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Urinalysis
- Screens for secondary hypertension and underlying renal disease.
- Findings:
- Proteinuria or haematuria suggests renal involvement.
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Electrocardiogram (ECG)
- Detects:
- Left ventricular hypertrophy.
- Past myocardial infarction or arrhythmias.
- A normal ECG does not exclude coronary artery disease.
- Detects:
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Fasting Metabolic Panel with eGFR
- Evaluates:
- Renal function (e.g., GFR and creatinine).
- Electrolyte imbalances (e.g., hypokalemia in hyperaldosteronism).
- Hyperglycemia, hypercalcemia, or hyperuricemia.
- Evaluates:
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Lipid Panel
- Hypertension frequently coexists with dyslipidemia.
- May reveal:
- Elevated LDL cholesterol.
- Low HDL cholesterol.
- Elevated triglycerides.
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Thyroid-Stimulating Hormone (TSH)
- Indicated if thyroid dysfunction is suspected.
- Abnormal results suggest hypo- or hyperthyroidism.
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Haemoglobin and Hematocrit
- Findings:
- Anaemia: Suggests chronic kidney disease.
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Polycythemia: Associated with pheochromocytoma.
- Findings:
Additional Investigations
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Plasma Renin Activity and Aldosterone Levels
- Indicated for:
- Unprovoked hypokalemia.
- Resistant hypertension or adrenal incidentaloma.
- Findings:
- Low renin and elevated aldosterone suggest primary hyperaldosteronism.
- Indicated for:
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Renal Imaging (Ultrasound, MRA, CT Angiography)
- Indicated in:
- Young patients (<40 years) with severe hypertension.
- Renal artery bruit.
- Detects:
- Renal artery stenosis or fibromuscular dysplasia.
- Indicated in:
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24-Hour Urine Catecholamines and Plasma Fractionated Metanephrines
- Indicated with signs of catecholamine excess (e.g., episodic hypertension, palpitations).
- Elevated levels suggest pheochromocytoma.
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Sleep Study
- Considered in:
- Resistant hypertension.
- Symptoms of obstructive sleep apnea (OSA) such as loud snoring, daytime fatigue, or morning headaches.
- Considered in:
-
24-Hour Urine Free Cortisol
- Indicated for suspected Cushing’s syndrome.
- Elevated levels confirm hypercortisolism.
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Echocardiography
- Assesses left ventricular function and hypertrophy.
- Provides prognostic insights in hypertensive patients.
Advanced Imaging
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Digital Subtraction Angiography (DSA):
- Gold standard for renal artery evaluation, though invasive and associated with risks such as contrast nephropathy.
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Carotid Doppler Ultrasound and Brain Imaging:
- Performed if cerebrovascular disease or carotid artery stenosis is suspected.
- Performed if cerebrovascular disease or carotid artery stenosis is suspected.
Cardiovascular Risk and Target-Organ Damage Assessment
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Ankle-Brachial Index (ABI)
- Indicates peripheral arterial disease if <0.9.
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Fundoscopy
- Detects hypertensive retinopathy:
- Arteriovenous nicking, hemorrhages, papilledema, or cotton-wool spots.
- Detects hypertensive retinopathy:
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Pulse Wave Velocity
- Predicts hypertension progression in younger adults (age 30–45).
- Predicts hypertension progression in younger adults (age 30–45).
Differential Diagnosis
Secondary Hypertension
Secondary hypertension, comprising 5-10% of cases, arises from identifiable underlying conditions. It is often suspected in patients with early-onset or resistant hypertension and should always be considered in younger or older patients presenting with hypertension.
Drug-Induced Hypertension
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Signs/Symptoms: History of drug use, including:
- Nonsteroidal anti-inflammatory drugs (NSAIDs), oral contraceptives, sympathomimetics, herbal remedies (e.g., liquorice, black cohosh), or certain immunosuppressants (e.g., cyclosporine, tacrolimus).
- Symptoms of acute intoxication, withdrawal, or cravings in cases of substance use (e.g., cocaine).
-
Investigations:
- Drug toxicology screen.
- Hypokalemia with excessive liquorice ingestion.
Renal Causes
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Chronic Kidney Disease (CKD):
- Signs/Symptoms: Pruritus, edema, or altered urine output.
-
Investigations:
- Elevated serum creatinine and albuminuria.
- Renal ultrasound may show sclerotic or polycystic kidneys.
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Renal Artery Stenosis:
- Signs/Symptoms: Difficult-to-control hypertension in younger patients or older individuals with atherosclerosis. Renal bruits may be present.
-
Investigations:
- Renal duplex ultrasound, magnetic resonance angiography (MRA), or CT angiography confirms diagnosis.
- Renal duplex ultrasound, magnetic resonance angiography (MRA), or CT angiography confirms diagnosis.
Endocrine Causes
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Hyperaldosteronism:
- Signs/Symptoms: Hypokalemia, mild hypernatremia, and metabolic alkalosis.
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Investigations:
- High plasma aldosterone and low renin levels.
- Failure of aldosterone suppression with salt loading.
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Cushing’s Syndrome:
- Signs/Symptoms: Weight gain, abdominal striae, moon face, dorsocervical fat pad.
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Investigations:
- Abnormal dexamethasone suppression test.
- Elevated 24-hour urine free cortisol or late-night salivary cortisol.
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Pheochromocytoma:
- Signs/Symptoms: Episodic hypertension, flushing, headaches, and palpitations.
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Investigations:
- Elevated urinary or plasma metanephrines and catecholamines.
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Thyroid Dysfunction:
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Hypothyroidism: Dry skin, cold intolerance, weight gain, and bradycardia.
- Elevated thyroid-stimulating hormone (TSH) and low free T4.
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Hyperthyroidism: Heat intolerance, weight loss, tachycardia, and tremors.
- Suppressed TSH and elevated free T4/T3.
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Hypothyroidism: Dry skin, cold intolerance, weight gain, and bradycardia.
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Hyperparathyroidism:
- Signs/Symptoms: Hypercalcemia, renal colic, or abdominal pain.
-
Investigations:
- Elevated parathyroid hormone (PTH) and serum calcium.
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Acromegaly:
- Signs/Symptoms: Acral enlargement (hands, feet, jaw).
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Investigations:
- Elevated insulin-like growth factor-1 (IGF-1).
- Lack of growth hormone suppression with glucose loading.
Cardiovascular Causes
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Coarctation of the Aorta:
- Signs/Symptoms: Differential BP between upper and lower limbs, absent femoral pulses.
-
Investigations:
- Echocardiography, CT angiography, or MRI.
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Collagen Vascular Disease:
- Signs/Symptoms: Sclerodactyly, vasculitis, or systemic lupus erythematosus manifestations.
-
Investigations:
- Positive autoimmune markers (e.g., anti-DNA, anti-Smith antibodies).
- Positive autoimmune markers (e.g., anti-DNA, anti-Smith antibodies).
Obstructive Sleep Apnea (OSA)
- Signs/Symptoms: Daytime somnolence, snoring, and choking during sleep.
-
Investigations:
- Polysomnography shows nocturnal oxygen desaturation.
- Polysomnography shows nocturnal oxygen desaturation.
Gestational Hypertension
- Signs/Symptoms: Hypertension detected after 20 weeks of gestation.
-
Investigations:
- Urinary albumin excretion to evaluate for pre-eclampsia.
- Urinary albumin excretion to evaluate for pre-eclampsia.
Rare Causes
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Congenital Adrenal Hyperplasia:
- Associated with hypokalemia, hypertension, and low renin levels.
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Drug-Induced Secondary Causes:
- Includes erythropoietin, chemotherapy agents (e.g., bevacizumab), and tyrosine kinase inhibitors.
- Includes erythropoietin, chemotherapy agents (e.g., bevacizumab), and tyrosine kinase inhibitors.
Management
Goals of Treatment
- Reduce mortality and morbidity related to cardiovascular and renal complications.
- Target Blood Pressure (BP):
- ACC/AHA: <130/80 mmHg for all adults with confirmed hypertension and cardiovascular risk ≥10%.
- ESC/ESH: <140/90 mmHg initially, with gradual reduction to <130/80 mmHg if well tolerated.
- WHO: <140/90 mmHg for general patients; <130/80 mmHg for high-risk groups.
Lifestyle Modifications
- Sodium reduction (<1.5 g/day), potassium supplementation (3.5–5.0 g/day), and adherence to the DASH diet.
- Weight loss to maintain BMI ~25 kg/m² and waist circumference <102 cm (men) or <88 cm (women).
- At least 150 minutes/week of moderate aerobic activity.
- Limit alcohol intake (<20–30 g/day for men, <10–20 g/day for women).
- Smoking cessation and managing dyslipidemia.
Pharmacologic Treatment
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Stage 1 Hypertension:
- Initiate with lifestyle changes; add monotherapy if cardiovascular risk ≥10%.
- Options: thiazide diuretics, ACE inhibitors, angiotensin-II receptor blockers (ARBs), or calcium channel blockers (CCBs).
-
Stage 2 Hypertension:
- Start with a combination of two drugs (e.g., ACE inhibitor + CCB).
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Resistant Hypertension:
- Add spironolactone or consider α-blockers, β-blockers, or hydralazine if uncontrolled with 3 drugs.
- Add spironolactone or consider α-blockers, β-blockers, or hydralazine if uncontrolled with 3 drugs.
Management of Hypertension: Comprehensive Approach
1. Treatment Goals
- The primary goal is to reduce cardiovascular and renal morbidity and mortality.
- Evidence-Based Targets:
- SPRINT Trial: Lowering systolic BP to 120 mmHg reduced cardiovascular events in high-risk adults without diabetes.
- HOPE-3 Trial: BP lowering benefits were significant only in patients with baseline systolic BP >143.5 mmHg.
2. Lifestyle Modifications
Lifestyle changes are foundational and include:
-
Diet:
- Sodium intake ≤1.5 g/day.
- Potassium-rich diet unless contraindicated.
- DASH diet: 8–10 servings of fruits and vegetables daily.
-
Physical Activity:
- 30 minutes of moderate aerobic exercise on most days.
-
Weight Management:
- Aim for BMI ~25 kg/m²; reduce abdominal obesity.
-
Alcohol Intake:
- Men: ≤2 drinks/day; Women: ≤1 drink/day.
-
Smoking Cessation:
- Improves vascular health but not directly linked to BP reduction.
-
Other:
- Discourage excess caffeine and recommend structured interventions for adherence.
- Discourage excess caffeine and recommend structured interventions for adherence.
3. Pharmacologic Therapy: Stepwise Approach
Step 1: Monotherapy
-
First-line Options:
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Angiotensin-Converting Enzyme (ACE) Inhibitors:
- Examples: Lisinopril, Ramipril, Enalapril.
- Mechanism: Inhibits the conversion of angiotensin I to angiotensin II, reducing vasoconstriction and aldosterone secretion.
- Indications:
- Preferred in younger patients (<55 years) without Black ancestry.
- Particularly effective in patients with diabetes, chronic kidney disease (CKD), or heart failure.
- Side Effects: Dry cough (due to bradykinin accumulation), angioedema, hyperkalemia.
- Contraindications: Pregnancy, history of angioedema, bilateral renal artery stenosis.
-
Angiotensin-II Receptor Blockers (ARBs):
- Examples: Losartan, Valsartan, Candesartan.
- Mechanism: Block angiotensin II from binding to its receptor, reducing vasoconstriction and aldosterone effects.
- Indications:
- First-line for patients intolerant to ACE inhibitors.
- Preferred in Black patients due to lower risk of adverse effects.
- Side Effects: Hyperkalemia, dizziness, rare angioedema.
- Contraindications: Same as ACE inhibitors.
-
Calcium Channel Blockers (CCBs):
- Examples: Amlodipine, Felodipine, Nifedipine (dihydropyridines).
- Mechanism: Inhibits calcium entry into vascular smooth muscle, promoting vasodilation.
- Indications:
- Effective across all age groups and ethnicities.
- Particularly useful in Black and elderly patients.
- Side Effects: Peripheral edema, headache, flushing.
- Non-dihydropyridine CCBs (e.g., Diltiazem, Verapamil) may be used in atrial fibrillation or angina but are less effective for BP reduction.
-
Thiazide or Thiazide-like Diuretics:
- Examples: Hydrochlorothiazide, Chlorthalidone, Indapamide.
- Mechanism: Inhibits sodium reabsorption in the distal tubule, reducing plasma volume.
- Indications:
- Effective as monotherapy or in combination.
- Preferred in Black patients and those with isolated systolic hypertension.
- Side Effects: Hypokalemia, hyponatremia, hyperuricemia, hyperglycemia.
- Contraindications: Gout, severe renal impairment.
-
Angiotensin-Converting Enzyme (ACE) Inhibitors:
Step 2: Dual Therapy
- If BP remains uncontrolled with monotherapy, a second antihypertensive agent from a different class should be added.
- Preferred Combination:
- ACE Inhibitor (or ARB) + CCB:
- Synergistic effect: ACE inhibitors/ARBs counteract fluid retention caused by CCBs.
- Example: Ramipril + Amlodipine.
- Alternatively:
- ACE Inhibitor (or ARB) + Thiazide Diuretic:
- Effective in patients with edema or heart failure.
- Example: Lisinopril + Chlorthalidone.
- CCB + Thiazide Diuretic:
- Useful in patients intolerant to renin-angiotensin system blockers.
- Example: Amlodipine + Hydrochlorothiazide.
- ACE Inhibitor (or ARB) + Thiazide Diuretic:
- ACE Inhibitor (or ARB) + CCB:
Step 3: Triple Therapy
- If BP remains uncontrolled on dual therapy, a combination of three drugs is recommended:
- ACE Inhibitor (or ARB).
- CCB.
- Thiazide or Thiazide-like Diuretic.
- Clinical Considerations:
- Ensure all drugs are titrated to optimal doses before escalating to triple therapy.
- Use fixed-dose combination pills where possible to improve adherence.
- Monitor for adverse effects such as electrolyte imbalances, particularly hypokalemia with diuretics.
Step 4: Resistant Hypertension
Resistant hypertension is defined as uncontrolled BP despite the use of three antihypertensive drugs, including a diuretic, at optimal doses.
-
Add-on Therapy:
-
Spironolactone (Preferred):
- Mechanism: Aldosterone antagonist, reduces sodium retention.
- Indications: Effective in resistant hypertension, particularly in primary aldosteronism.
- Dose: Typically 25–50 mg daily.
- Side Effects: Hyperkalemia, gynecomastia (less with eplerenone).
- Contraindications: Severe renal impairment, hyperkalemia.
-
Eplerenone:
- Alternative to spironolactone with fewer endocrine side effects.
-
Spironolactone (Preferred):
-
Alternative Agents:
-
α-Blockers:
- Examples: Doxazosin, Prazosin.
- Mechanism: Reduce vascular resistance via alpha-1 receptor blockade.
- Indications: Considered for patients with concurrent benign prostatic hyperplasia (BPH).
- Side Effects: Orthostatic hypotension, dizziness.
-
β-Blockers:
- Examples: Bisoprolol, Carvedilol.
- Indications: Effective in patients with heart failure, atrial fibrillation, or post-myocardial infarction.
- Side Effects: Bradycardia, fatigue, worsening asthma.
-
Hydralazine:
- Mechanism: Direct arterial vasodilation.
- Indications: Reserved for refractory cases due to side effects.
- Side Effects: Reflex tachycardia, lupus-like syndrome.
-
α-Blockers:
-
Other Considerations:
- Minoxidil: Potent vasodilator used in rare cases of severe, refractory hypertension. Requires co-prescription of a diuretic and β-blocker.
- Evaluate for secondary causes of hypertension if resistant hypertension persists despite optimal therapy.
Monitoring and Adjustments
- Regularly monitor BP, renal function, and electrolytes during therapy.
- Use home BP monitoring (HBPM) or ambulatory BP monitoring (ABPM) to confirm control and assess white-coat or masked hypertension.
- Tailor therapy based on individual response, tolerability, and comorbidities.
4. Comorbid Conditions
-
Chronic Kidney Disease (CKD):
- ACE inhibitors or ARBs reduce proteinuria and slow progression.
-
Heart Failure:
- Reduced ejection fraction: ACE inhibitors, β-blockers, aldosterone antagonists.
- Preserved ejection fraction: Diuretics for volume control.
-
Diabetes Mellitus:
- ACE inhibitors or ARBs preferred to protect against nephropathy.
- Avoid intensive systolic BP targets <120 mmHg.
-
Atrial Fibrillation:
- β-blockers or non-dihydropyridine CCBs (e.g., diltiazem).
- β-blockers or non-dihydropyridine CCBs (e.g., diltiazem).
5. Monitoring and Follow-Up
-
Target BP:
- <140/90 mmHg in most adults.
- <130/80 mmHg for high-risk patients (e.g., diabetes, CKD).
- Annual review of BP control, adherence, and cardiovascular risk.
Prognosis
-
Association Between BP Levels and Outcomes:
-
Cardiovascular Risk:
- Every 20 mmHg rise in systolic BP (SBP) or 10 mmHg rise in diastolic BP (DBP) doubles the risk of ischemic heart disease and stroke mortality.
- Systolic BP has a more pronounced effect on cardiovascular outcomes compared to diastolic BP, but both independently increase risks.
-
Atherosclerosis and End-Organ Damage:
- Untreated mild-to-moderate hypertension increases the risk of atherosclerotic disease by 30% and organ damage by 50% within 8–10 years of onset.
-
Resistant Hypertension:
- Associated with poor outcomes, especially in patients with chronic kidney disease (CKD) or ischemic heart disease.
- Effective BP control reduces risks for stroke, coronary heart disease, and heart failure.
-
Cardiovascular Risk:
-
Impact of BP Control:
- Clinical trials have demonstrated significant benefits of antihypertensive therapy:
- Stroke: 35–40% reduction in incidence.
- Myocardial Infarction: 20–25% reduction in occurrence.
- Heart Failure: >50% reduction in incidence.
- Achieving a sustained 12 mmHg reduction in systolic BP over 10 years prevents:
- 1 death per 11 patients with stage 1 hypertension and cardiovascular risk factors.
- 1 death per 9 patients with cardiovascular disease or end-organ damage.
- Clinical trials have demonstrated significant benefits of antihypertensive therapy:
-
Prognostic Impact of Specific Conditions:
-
Hypertensive Retinopathy:
- Associated with an increased long-term stroke risk, even with controlled BP.
- Moderate-to-severe retinopathy increases stroke risk 2.37-fold.
-
Diabetes Mellitus:
- Hypertensive patients with diabetes experience a 57% higher risk of cardiovascular events and a 72% higher all-cause mortality risk.
- Ambulatory BP monitoring indicates that nocturnal BP reduction ("asleep BP") is the strongest predictor of event-free survival.
-
Chronic Kidney Disease (CKD):
- Hypertension-induced nephrosclerosis is a leading cause of end-stage renal disease (ESRD).
- Black patients face a higher ESRD risk, even with well-controlled BP.
-
Hypertensive Retinopathy:
Long-Term Outcomes
-
Morbidity and Mortality:
- Meta-analyses show increasing SBP and DBP correlate with rising cardiovascular and cerebrovascular mortality.
- For prehypertension (120–139/80–89 mmHg), patients face a 66% increased stroke risk, with those in the high range (130–139/85–89 mmHg) having a 95% increased risk.
-
Hypertensive Emergencies:
- Mortality risk depends on the severity of end-organ dysfunction at presentation.
- With BP control and medication adherence, 10-year survival after hypertensive crises approaches 70%.
-
All-Cause Mortality Trends:
- While mortality among hypertensive adults has decreased over time, it remains significantly higher than in normotensive individuals.
- While mortality among hypertensive adults has decreased over time, it remains significantly higher than in normotensive individuals.
Prognostic Impact of BP Variability
- BP variability is an independent risk factor for adverse cardiovascular outcomes.
- Studies, such as the ACCORD trial, suggest limited benefits of aggressive BP control in diabetes for reducing cardiovascular events, though stroke incidence decreases modestly.
Uncontrolled and Masked Hypertension
-
White-Coat Hypertension:
- Associated with increased cardiovascular events and all-cause mortality when untreated.
- No proven benefit of treating white-coat hypertension based on current evidence.
-
Masked Hypertension:
- Linked to higher prevalence of target organ damage and cardiovascular events compared to normotensive individuals.
- Preliminary data suggest potential benefits of treatment, but more research is needed.
Complications
Major Complications
Cardiovascular System
-
Coronary Heart Disease (CHD) and Myocardial Infarction (MI):
- Mechanism: Chronic hypertension accelerates atherosclerosis, increasing myocardial oxygen demand and reducing coronary perfusion.
- Risk: For every 20/10 mmHg increase in BP, the lifetime risk of mortality from ischemic heart disease doubles.
- Management: Aggressive BP control, lipid management, and antiplatelet therapy.
-
Left Ventricular Hypertrophy (LVH):
- Prevalence: Seen in >30% of hypertensive patients.
- Impact: Strongly linked to cardiovascular morbidity and mortality.
- Treatment: ACE inhibitors, ARBs, and aldosterone antagonists reduce LVH and improve outcomes.
-
Congestive Heart Failure (CHF):
- Prevalence: Hypertensive patients are three times more likely to develop CHF.
- Mechanism: Hypertension contributes to systolic and diastolic dysfunction.
- Management: ACE inhibitors, ARBs, β-blockers, aldosterone antagonists, and SGLT2 inhibitors reduce mortality; diuretics alleviate fluid overload.
-
Aortic Aneurysm and Dissection:
- Prevalence: Over 70% of aortic dissection cases have a history of hypertension.
- Impact: High mortality, especially with proximal (type A) dissections.
- Prevention: BP control is critical to reduce aortic wall stress.
-
Peripheral Artery Disease (PAD):
- Impact: Hypertension increases the risk of myocardial infarction, stroke, and heart failure in PAD patients.
- Management: Antihypertensive therapy reduces systemic cardiovascular risks.
Cerebrovascular System
-
Stroke:
- Types: Ischemic stroke and intracerebral hemorrhage.
- Risk: Stroke risk increases linearly with BP levels; for every 20/10 mmHg increase above 115/75 mmHg, mortality doubles.
- Management: BP control reduces the risk of primary and recurrent strokes.
-
Hypertensive Encephalopathy:
- Mechanism: Acute BP elevation leads to cerebral edema and neurological dysfunction.
- Management: Requires rapid BP reduction in controlled settings.
Renal System
-
Chronic Kidney Disease (CKD):
- Impact: Hypertension is a leading cause of CKD and end-stage renal disease (ESRD).
- Disparities: Black patients have a higher risk of ESRD despite BP control.
- Management: ACE inhibitors and ARBs slow CKD progression by reducing proteinuria.
-
Hypertensive Nephrosclerosis:
- Prevalence: Common among long-standing hypertensive patients.
- Outcome: May progress to ESRD without intervention.
Ocular System
-
Hypertensive Retinopathy:
- Findings: Includes arteriolar narrowing, haemorrhages, cotton-wool spots, and papilledema.
- Impact: Associated with increased stroke risk and cardiovascular events.
- Screening: Fundoscopic exams are recommended for hypertensive patients.
-
Retinal Vascular Occlusion:
- Risk: Hypertension predisposes patients to retinal vein and artery occlusions.
- Risk: Hypertension predisposes patients to retinal vein and artery occlusions.
Other Complications
-
Hypertensive Emergencies:
- Definition: Severe BP elevation (>180/120 mmHg) with acute end-organ damage.
- Management: Requires immediate BP reduction in a monitored setting.
-
Orthostatic Hypotension:
- Prevalence: Affects ~10% of hypertensive adults, particularly elderly patients.
- Management: Optimize antihypertensive therapy and monitor for postural symptoms.
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