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Hypertension

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    Systemic Hypertension:
    • Defined as persistently elevated office systolic blood pressure (SBP) ≥140 mmHg and/or diastolic blood pressure (DBP) ≥90 mmHg, measured on at least two separate occasions, typically spaced at least 1–2 weeks apart.
    Isolated Systolic Hypertension:
    • Defined as persistently elevated SBP ≥140 mmHg with a normal DBP (<90 mmHg).
    • This condition is more common in older adults due to decreased arterial compliance.

    Hypertension is a significant global health challenge and a major contributor to the burden of cardiovascular diseases (CVDs).

    • Global Perspective: In the 20th century, CVDs accounted for fewer than 10% of deaths worldwide, rising to approximately 30% today. A staggering 80% of these deaths now occur in low- and middle-income countries.
    • Nigerian Context:
      • An estimated 25% of Nigerians are hypertensive, primarily affecting the middle- and top-level workforce.
      • This has profound implications for national productivity and the economy.
      • Hypertension accounts for 30% of clinic visits among individuals aged 45–64 years (Ogunniyi). This age group experiences approximately 1,021 clinic visits per 1,000 individuals (Cherry, 2008).
      • Emergency admissions linked to hypertension make up a quarter of cases in Nigerian hospitals (Ekere).


    Category Systolic blood pressure (mmHg) Diastolic blood pressure
    Optimal blood pressure <120 <80
    Normal blood pressure <130 <85
    High-normal blood pressure 130-139 85-89
    Grade 1 Hypertension (mild) 140-159 90-99
    Grade 2 Hypertension (moderate) 160-179 100-109
    Grade 3 Hypertension (severe) ≥180 ≥110
    Isolated Systolic Hypertension (Grade 1) 140-159 <90
    Isolated Systolic Hypertension (Grade 2) ≥160 <90

    Diagnosis of Hypertension (HTN)

    Hypertension is diagnosed based on elevated blood pressure (BP) measured through various methods:

    1. Conventional Office BP Measurement:
      • SBP ≥140 mmHg and/or DBP ≥90 mmHg
    2. Home BP Monitoring:
      • SBP ≥135 mmHg and/or DBP ≥85 mmHg
    3. Ambulatory Blood Pressure Monitoring (ABPM):
      • Daytime (awake): SBP ≥135 mmHg and/or DBP ≥85 mmHg
      • Nighttime (asleep): SBP ≥120 mmHg and/or DBP ≥70 mmHg
      • 24-hour average: SBP ≥130 mmHg and/or DBP ≥80 mmHg

    1. Primary/Essential Hypertension (90% of cases):
      • Multifactorial with genetic (40–60%) and environmental influences.
    2. Secondary Hypertension:
      • Caused by an identifiable underlying condition.

    1. Essential Hypertension (Primary Hypertension):
      • Accounts for 90–95% of hypertension cases.
      • It is multifactorial, with both genetic and environmental influences:
        • Genetic Predisposition:
          • Normal parents: Offspring risk = 2.6%.
          • One hypertensive parent: Risk doubles to 5.7%.
          • Both hypertensive parents: Risk increases tenfold to 27.2%.
        • Environmental and Lifestyle Factors:
          • Obesity
          • Low birth weight (fetal factors)
          • Metabolic Syndrome (Syndrome X): Combination of hypertension, diabetes mellitus, dyslipidemia, and obesity.
    2. Secondary Hypertension:
      • Accounts for 5–10% of hypertension cases.
      • Occurs due to identifiable underlying causes, including:
        • Lifestyle-Related Factors:
          • Excessive alcohol consumption
          • Obesity
          • Pregnancy-induced hypertension
        • Renal Causes:
          • Renovascular disease (e.g., renal artery stenosis)
          • Chronic kidney disease
          • Glomerulonephritis
          • Polycystic kidney disease
        • Endocrine Disorders:
          • Thyrotoxicosis
          • Pheochromocytoma
          • Cushing's syndrome
          • Conn's syndrome (Primary hyperaldosteronism)
          • Secondary hyperaldosteronism
          • Congenital adrenal hyperplasia
          • Hyperparathyroidism
          • Acromegaly
        • Drug-Induced Hypertension:
          • Oral contraceptive pills (OCP)
          • Estrogens
          • Anabolic steroids/Chronic steroid therapy
          • Corticosteroids
          • Nonsteroidal anti-inflammatory drugs (NSAIDs)
          • Sympathomimetics
          • Carbenoxolone
        • Cardiovascular Causes:
          • Coarctation of the aorta
        • Other Causes:
          • Sleep apnea

    Special Consideration

    • White Coat Hypertension:
      • Elevated BP due to anxiety in clinical settings.
      • Confirm diagnosis using Home BP Monitoring (≥135/85 mmHg) or Ambulatory BP Monitoring (ABPM).

    1. Blood Vessels:
      • Arterial Wall Thickening:
        • Atherosclerosis
        • Widespread atheroma contributing to Coronary Artery Disease (CAD) and Cerebrovascular Disease (CVD), particularly in individuals with risk factors such as smoking, diabetes mellitus (DM), or hyperlipidemia.
      • Aortic Pathologies:
        • Aortic aneurysm
        • Aortic dissection
      • Note: Increased peripheral resistance reduces renal blood flow, activating the Renin-Angiotensin-Aldosterone System (RAAS), perpetuating hypertension.
    2. Central Nervous System (CNS):
      • Carotid Atheroma
      • Transient Ischaemic Attack (TIA)
      • Stroke:
        • Due to haemorrhage or infarction
      • Subarachnoid Haemorrhage (SAH)
      • Hypertensive Encephalopathy:
        • Defined as severe hypertension with neurological symptoms:
          • Drowsiness, altered sensorium
          • Transient disturbances of speech/vision
          • Paraesthesia, disorientation
          • Seizures, loss of consciousness (LOC)
          • Papilledema
      • Note: Neurological deficits are reversible with effective BP control.
    3. Retina (Hypertensive Retinopathy):
      • Graded based on severity:
        • Grade 1:
          • Arterial thickening, tortuosity, and increased reflectiveness (termed "silver wiring").
        • Grade 2:
          • Grade 1 findings + arteriovenous (AV) nipping (compression of veins by thickened arteries).
        • Grade 3:
          • Grade 2 findings + evidence of retinal ischaemia, such as:
            • Flame or blot haemorrhages
            • Cotton wool spots/soft exudates
        • Grade 4:
          • Grade 3 findings + papilledema (optic disc swelling).
      • Note: Grades 3 and 4 hypertensive retinopathy are diagnostic of malignant hypertension. Hypertension is also associated with central retinal vein thrombosis.
    4. Heart:
      • Coronary Artery Disease (CAD)
      • Left Ventricular Hypertrophy (LVH): A marker of cardiovascular risk.
      • Atrial Fibrillation: Can result from LVH or CAD.
      • Heart Failure:
        • Most commonly left ventricular failure.
    5. Kidneys:
      • Proteinuria
      • Progressive Renal Failure
      • Hypertensive Nephrosclerosis

    History Taking in Hypertension

    1. Presenting Complaints:
      • Common Presentation:
        • Often asymptomatic, detected during routine checks.
        • Non-specific symptoms may include headache, weakness, and insomnia.
      • Symptoms Suggestive of Underlying Causes:
        • Pheochromocytoma: Paroxysmal headaches, palpitations.
        • Thyrotoxicosis: Proptosis with or without goiter.
      • Complications:
        • Symptoms typically result from target organ damage:
          • Neurological: Stroke, hypertensive encephalopathy.
          • Cardiovascular: Chest pain, myocardial infarction.
          • Renal: Reduced urine output, proteinuria.
    2. History of Presenting Complaint (HPC):
      • Complaint: Clarify symptoms and their onset.
      • Course: Understand the progression and fluctuations.
      • Causes: Explore potential underlying conditions (e.g., endocrine, renal, or cardiovascular).
      • Complications: Probe for signs of organ damage:
        • Vision disturbances, chest pain, breathlessness, or neurological deficits.
      • Care so far: Ask about prior evaluations, medications, or treatments.
    3. Past Medical History (PMH):
      • Investigate the presence of:
        • Chronic conditions like diabetes or renal disorders (e.g., glomerulonephritis, polycystic kidney disease).
        • Pregnancy-related complications such as preeclampsia or eclampsia.
    4. Family History:
      • Look for a family history of:
        • Hypertension
        • Diabetes Mellitus
        • Polycystic Kidney Disease (PKD)
    5. Social History:
      • Smoking habits
      • Alcohol consumption
      • High-cholesterol diet
      • Exercise habits
    6. Drug History:
      • Explore use of medications or substances that may contribute to hypertension:
        • Sympathomimetics
        • Oral contraceptives
        • NSAIDs
    7. Systemic Review: Conduct a detailed review of all systems to uncover any hidden symptoms or complications.

    Physical Examination Approach

    Always follow the "IPPA" approach:

    • Inspection
    • Palpation
    • Percussion
    • Auscultation

    General Examination

    • Weight and Height:
      • To calculate Body Mass Index (BMI) and assess for obesity.
    • Characteristic Features:
      • Cushing's syndrome: Moon-shaped face, red cheeks.
      • Thyrotoxicosis: Bulging eyes (proptosis), goitre.
      • Hyperlipidaemia: Xanthomas, atheromas (e.g., around the eyes).
    • Routine General Examination:
      • Essentially normal in essential hypertension unless there are signs of organ damage or secondary causes.

    Cardiovascular System (CVS)

    • Pulse:
      • Regularity, rate, and rhythm.
    • Blood Pressure (BP):
      • Elevated BP >140/90 mmHg (diagnostic of hypertension).
    • Jugular Venous Pressure (JVP):
      • Elevated JVP or distended neck veins suggest heart failure.
    • Precordial Examination:
      • Locomotor brachialis (sign of arterial stiffness).
      • Radioradial/radiofemoral delay: Suggestive of coarctation of the aorta.
      • Irregularly irregular pulse: Seen in atrial fibrillation.
      • Small volume pulse: Indicative of heart failure.
      • Apical heave: Suggestive of left ventricular hypertrophy (LVH).
      • Loud A2: Increased intensity of the second heart sound, indicative of systemic hypertension.
      • S4 or S3 heart sounds: Present in heart failure.

    Abdominal Examination

    • Distended Abdomen:
      • Associated with central obesity (metabolic syndrome).
    • Striae:
      • Purple striae in Cushing's syndrome.
    • Pulsating Abdominal Mass:
      • Suggestive of aortic aneurysm.
    • Enlarged Kidney:
      • May suggest Polycystic Kidney Disease (PKD).
    • Renal Bruit:
      • Suggestive of renal artery stenosis (RAS).

    Fundoscopy

    Examine the retina to assess for hypertensive retinopathy and determine the extent of damage (Grades 1-4):

    • Grade 1: Arterial thickening, tortuosity.
    • Grade 2: Arteriovenous nipping.
    • Grade 3: Retinal ischaemia, cotton wool spots, and haemorrhages.
    • Grade 4: Papilledema (indicative of malignant hypertension).

    Features of Long-standing Hypertension

    • Locomotor brachialis (stiffening of arteries).
    • Thickened arterial wall.
    • Displaced apex beat (due to LVH).
    • Loud A2 (heart sound).
    • Grade II hypertensive retinopathy or higher.

    Investigations in Hypertension

    Specific Investigations

    1. 12-Lead ECG:
      • Detects atrial fibrillation, chamber enlargement (e.g., left ventricular hypertrophy (LVH)), and signs of coronary artery disease (CAD).
    2. Chest X-ray:
      • Assesses for cardiomegaly (cardiothoracic ratio [CTR] >50%) and signs of heart failure (e.g., unfolding of the aorta).
    3. Echocardiogram (Echo):
      • Evaluates for LVH and assesses ejection fraction (<0.4 indicates heart failure).
    4. Ambulatory Blood Pressure Monitoring (ABPM):
      • Provides a 24-hour BP profile; add 10/5 mmHg to the average ambulatory BP reading to estimate clinic BP value.

    General Investigations

    1. Urinalysis:
      • Check for blood, protein, and glucose to assess for renal involvement or diabetes.
    2. Electrolytes, Urea, and Creatinine (E, U/Cr):
      • Potassium (K): Elevated in Conn's syndrome (primary hyperaldosteronism).
      • Calcium (Ca²⁺): Elevated in hyperparathyroidism.
    3. Blood Glucose Testing:
      • Fasting Blood Sugar (FBS) or Random Blood Sugar (RBS) to rule out diabetes mellitus (DM).
    4. Serum Cholesterol Levels:
      • Total cholesterol and HDL cholesterol to screen for hyperlipidaemia.
    5. Renal Ultrasound (Renal USS):
      • To rule out renal disease such as polycystic kidney disease (PKD) or other structural abnormalities.
    6. Renal Angiography:
      • To rule out renal artery stenosis (RAS), a common cause of secondary hypertension.
    7. 24-Hour Urinary Metanephrines:
      • To rule out pheochromocytoma, a tumour of the adrenal medulla that can cause secondary hypertension.
    8. Urinary Cortisol and Dexamethasone Suppression Test:
      • To rule out Cushing's syndrome, characterized by excess cortisol production.
    9. Plasma Renin Activity & Aldosterone:
      • To rule out primary aldosteronism, a condition caused by excess aldosterone.
    10. CT Scan:
      • Brain CT: To assess for haemorrhage in and around the basal ganglia, which may suggest hypertensive encephalopathy.
      • Abdominal CT: To identify adrenal masses that may indicate pheochromocytoma.
    Routine investigations

    Treatment of Hypertension

    Indications for Treatment

    • Offer treatment if:
      • BP ≥160/100 mmHg
      • Isolated systolic hypertension with SBP ≥160 mmHg
      • BP >140/90 mmHg and CVD risk ≥20%, or existing CVD or target organ damage.

    Target BP Goals

    • Clinic BP ≤140/90 mmHg
    • <130/80 mmHg in diabetic patients
    • <150/90 mmHg if aged 80 or older

    Monitoring

    • Schedule 3-monthly clinic appointments to monitor BP, minimize side effects of medications, and reinforce lifestyle advice.
    Hypertension guideline management algorithm

    Non-Drug Therapy (Lifestyle Modification)

    The aim is to:

    • Prevent the need for medications,
    • Use lower doses of medications in established cases,
    • Reduce CVD risk.

    Key lifestyle changes include:

    • Correct obesity through diet and exercise.
    • Reduce alcohol intake.
    • Restrict salt intake to <2g/day.
    • Regular physical exercise: At least 30 minutes of brisk walking 5 times a week.
    • Increase consumption of fruits and vegetables.
    • Quit smoking and follow a diet low in saturated fat; eat fish to further reduce CVD risk.

    Benefits of Lifestyle Modification in Hypertension Management

    Lifestyle modification is a cornerstone in managing hypertension, offering effective, low-cost, and wide-reaching benefits. Below are key strategies and their impact:

    • Weight Reduction
      • Target: Maintain a BMI of 18.5–24.9.
      • BP Reduction: 5–20 mmHg per 10 kg weight loss.
      • Additional Benefits: Improves insulin sensitivity, reduces cardiovascular risk.
    • Dietary Modifications
      • DASH Diet:
        • Emphasizes fruits, vegetables, low-fat dairy, and reduced saturated fats.
        • BP Reduction: 8–14 mmHg.
      • Sodium Reduction:
        • Limit intake to 2.4 g sodium (6 g salt) daily.
        • BP Reduction: 2–8 mmHg.
    • Physical Activity
      • Recommendation: Regular aerobic exercise (e.g., brisk walking) for at least 30 minutes most days.
      • BP Reduction: 4–9 mmHg.
      • Additional Benefits: Enhances cardiovascular health and metabolic function.
    • Smoking Cessation
      • Impact: Minimal direct effect on BP but significantly reduces overall cardiovascular risk.
      • Advice: Counsel all hypertensive smokers to quit.
    Lifestyle modifications to manage hypertension

    Drug Therapy (Antihypertensive Drugs)

    1. Thiazides and Diuretics:

    • Bendroflumethiazide (2.5 mg daily)
    • Cyclopenthiazide (0.5 mg daily)
    • Furosemide (40 mg daily) or Bumetanide (1 mg daily).
    • Note: Loop diuretics are poor antihypertensives.
    • Thiazide-like diuretics (e.g., Indapamide) are preferred.

    2. Angiotensin-Converting Enzyme Inhibitors (ACEIs):

    • Enalapril (20 mg daily)
    • Ramipril (5-10 mg daily)
    • Lisinopril (10-40 mg daily).
    • Caution: In patients with impaired renal function or renal artery stenosis. Check E, U/Cr before starting and 1-2 weeks after initiation.
    • Side effects: First-dose hypotension, cough, rash, hyperkalemia, and renal dysfunction.

    3. Angiotensin Receptor Blockers (ARBs):

    • Valsartan (40-160 mg daily).
    • Advantage: Fewer side effects compared to ACEIs.

    4. Calcium Channel Blockers (CCBs):

    • Dihydropyridines: (e.g., Amlodipine 5-10 mg daily, Nifedipine 30-90 mg daily).
      • Useful in the elderly.
      • Side effects: Flushing, palpitations, fluid retention.
    • Non-dihydropyridines: (e.g., Diltiazem 200-300 mg daily, Verapamil 240 mg daily).
      • Particularly useful in ischemic heart disease.

    5. Beta-Blockers (B-blockers):

    • Not used as first-line therapy except for patients with specific indications, such as angina.
    • Examples:
      • Metoprolol (100-200 mg daily)
      • Atenolol (50-100 mg daily)
      • Bisoprolol (5-10 mg daily).

    6. Alpha-Blockers:

    • Prazosin, Doxazosin.

    7. Other Vasodilators:

    • Hydralazine, Minoxidil.
    • Used in severe hypertension or cases with poor response to other treatments.

    8. Centrally Acting Drugs:

    • Medications that act on the central nervous system to reduce BP.

    9. Labetalol and Carvedilol:

    • Labetalol: 200 mg-2.4 g daily (in divided doses).
    • Carvedilol: 6.25-25 mg 12-hourly.
    • Labetalol infusion is used in malignant hypertension.

    Stepwise Use of Antihypertensive Drugs

    1. Step 1: Initial Treatment

    • Calcium Channel Blockers (CCBs) or Diuretics: Start with either a CCB (e.g., Amlodipine) or a diuretic (e.g., Indapamide or Bendroflumethiazide) as the first-line treatment.

    2. Step 2: Add a Second Drug

    • ACE Inhibitors (ACEI) or Angiotensin Receptor Blockers (ARBs): Combine either an ACEI (e.g., Enalapril, Ramipril) or an ARB (e.g., Valsartan) with the initial drug (i.e., A + C or A + D).

    3. Step 3: Add a Third Drug

    • Three-drug combination: If blood pressure control is not achieved, add a third drug from the following classes:
      • ACEI/ARB + CCB + Diuretic (i.e., A + C + D).

    4. Step 4: Add Additional Drugs and Consider Specialist Referral

    • Further Diuretics (e.g., Spironolactone).
    • Alpha Blockers (e.g., Prazosin, Doxazosin).
    • Beta-Blockers (e.g., Metoprolol, Atenolol).
    • If blood pressure remains poorly controlled despite optimal doses of these drugs, consider specialist referral.
    Clinical trial and guideline basis for compelling indications for individual drug classes
    Compelling and possible indications contraindications and cautions for the major classes

    Adjuvant Drug Therapy

    1. Aspirin (Antiplatelet Therapy):

    • Indication: Reduce CVD risk, particularly in patients with well-controlled BP and existing target organ damage, diabetes, or a 10-year CAD risk ≥15%.
    • Risk: May increase the risk of bleeding, including intracerebral bleeding in some patients. The benefits generally outweigh the risks in those over 50 years old with well-controlled BP.

    2. Statins:

    • Indication: Strongly indicated in patients with established vascular disease or a 10-year CVD risk ≥20% to reduce cholesterol and CVD risk.
    • Note: Statins help to stabilize atherosclerotic plaques and reduce further cardiovascular events.

    How Long Are Antihypertensives Used For?

    • Lifelong for most people, especially in primary (essential) hypertension.
    • Temporary in secondary hypertension if the underlying cause is treated (e.g., surgery for a tumor).
    • Lifestyle changes can reduce the dose but rarely eliminate the need for medication.

    • Definition: Resistant hypertension is diagnosed when a patient’s systolic blood pressure remains poorly controlled despite adherence to optimal doses of at least three classes of antihypertensive drugs, including a diuretic. If blood pressure control is still not achieved, the use of four or more drugs may be necessary.

    Causes

    • Nonadherence
    • Inadequate doses
    • Inappropriate combinations
    • Drugs: NSAID, Cocaine, amphetamines
    • Sympathomimetics (decongestants, anorectics)
    • Obesity
    • Excess alcohol intake
    • Contraceptives
    • Erythropoetin
    • Secondary causes of hypertension
    • Improper BP measurement
    • OTC interactions
    • Inadequate diuresis

    A hypertensive emergency is characterized by a markedly elevated blood pressure (BP ≥180/120 mmHg) with acute end-organ damage that requires immediate intervention using parenteral antihypertensives over minutes to hours. It is more common in younger patients and Black individuals.

    Target Organ Damage:

    • Blood Vessels:
      • Thickened arterial walls
      • Widespread atheroma causing Coronary Artery Disease (CAD), Cerebrovascular Disease (CVD)
    • CNS (Central Nervous System):
      • Stroke (from hemorrhage or infarction)
      • Transient Ischemic Attack (TIA)
      • Subarachnoid Hemorrhage (SAH)
      • Hypertensive Encephalopathy
    • Retina:
      • Hypertensive Retinopathy: retinal hemorrhages, exudates, and possibly papilledema
    • Heart:
      • Coronary Artery Disease (CAD)
      • Left Ventricular Hypertrophy (LVH)
      • Atrial Fibrillation following LVH or CAD
      • Heart Failure, especially Left Ventricular Failure (LVF)
    • Kidneys:
      • Proteinuria
      • Progressive renal failure

    Hypertensive Urgency vs. Emergency

    • Hypertensive Emergency: BP ≥180/120 mmHg with acute end-organ damage. Requires immediate parenteral antihypertensives.
    • Hypertensive Urgency: BP ≥180/120 mmHg without acute organ damage. Managed with oral antihypertensives over hours to days. Avoid sudden drops in BP due to poor cerebral autoregulation, increasing stroke risk.

    Malignant Hypertension & Accelerated Hypertension

    • Malignant Hypertension:
      • Rare, but severe, form of hypertensive emergency characterized by:
        • Severe hypertension
        • Rapidly progressive end-organ damage
        • Bilateral retinal hemorrhages and exudates, ± papilledema
        • Left ventricular failure (LVF) leading to death if untreated
    • Accelerated Hypertension:
      • Recent significant increase over baseline BP associated with target organ damage.

    Symptoms of Hypertensive Emergency

    • Headache
    • Visual disturbances (e.g., blurred vision, blindness)
    • May precipitate acute renal failure, heart failure, or encephalopathy.

    Management of Hypertensive Emergency

    1. Admit to ICU:
      • Strict blood pressure monitoring
      • Frequent neurologic status assessment
      • Frequent urine output monitoring
    2. IV Antihypertensive Therapy:
      • Sodium Nitroprusside or Labetalol (for rapid control)
        • Sodium Nitroprusside: Start with 0.5 µg/kg/min IV, titrate up to 8 µg/kg/min
        • Labetalol: 50 mg IV over 1 minute, repeat every 5 minutes (max 300 mg/day)
    3. Blood Pressure Goals:
      • Reduce BP to a target of ~110 mmHg diastolic over the first 4 hours
      • MAP (Mean Arterial Pressure) should be reduced by 20-25% over 1-2 hours
      • Subsequent BP reduction over the next 24 hours
      • Maintain BP in the first 24 hours at no less than 160/110 mmHg
    4. Avoid Use of Sublingual Nifedipine:
      • Never use sublingual nifedipine as it can cause a dangerous drop in BP and increase stroke risk.

    Drugs Used in Hypertensive Emergency

    • Labetalol
    • Nicardipine / Clevidipine
    • Nitroprusside
    • Nitroglycerin
    • Urapidil
    • Esmolol
    • Phentolamine (used for pheochromocytoma crisis)

    Notes:

    • Hydralazine may be used in pregnant women.
    • After BP control, switch to oral antihypertensives for long-term management.
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