Hypertension, commonly known as high blood pressure, is a chronic medical condition in which the blood pressure in the arteries is persistently elevated. It is a major risk factor for cardiovascular diseases, including stroke, heart attack, heart failure, and aneurysm, and can also lead to kidney failure, vision loss, and cognitive decline. Understanding hypertension involves exploring its classification, causes, pathophysiology, symptoms, diagnosis, treatment, and prevention.
 Classification of Hypertension
Hypertension is classified based on blood pressure measurements:
1. Normal Blood Pressure: Systolic < 120 mm Hg and Diastolic < 80 mm Hg.
2. Elevated Blood Pressure: Systolic 120-129 mm Hg and Diastolic < 80 mm Hg.
3. Hypertension Stage 1: Systolic 130-139 mm Hg or Diastolic 80-89 mm Hg.
4. Hypertension Stage 2: Systolic ≥ 140 mm Hg or Diastolic ≥ 90 mm Hg.
5. Hypertensive Crisis: Systolic > 180 mm Hg and/or Diastolic > 120 mm Hg, requiring immediate medical attention.
 Causes of Hypertension
Hypertension can be classified into two main types based on its causes:
1. Primary (Essential) Hypertension:
– Accounts for 90-95% of cases.
– No identifiable cause; likely a result of genetic and environmental factors.
– Risk factors include age, family history, high salt intake, obesity, physical inactivity, alcohol consumption, and stress.
2. Secondary Hypertension:
– Accounts for 5-10% of cases.
– Caused by underlying medical conditions or medications.
– Common causes include kidney disease, endocrine disorders (e.g., hyperthyroidism, Cushing’s syndrome), obstructive sleep apnea, and certain medications (e.g., oral contraceptives, NSAIDs).
 Pathophysiology of Hypertension
The pathophysiology of hypertension involves complex interactions between genetic, environmental, and lifestyle factors that affect cardiovascular and renal systems. Key mechanisms include:
1. Increased Cardiac Output: Elevated blood volume or heart rate increases cardiac output.
2. Increased Peripheral Resistance: Constriction of arterioles due to overactivity of the sympathetic nervous system, the renin-angiotensin-aldosterone system (RAAS), and endothelial dysfunction.
3. Renal Dysfunction: Impaired ability of the kidneys to excrete sodium, leading to fluid retention and increased blood volume.
4. Vascular Remodeling: Structural changes in the blood vessels, including thickening of the arterial walls, reduce their elasticity and increase resistance.
 Symptoms of Hypertension
Hypertension is often called the “silent killer” because it typically has no symptoms until significant damage has occurred. When symptoms do appear, they may include:
– Headaches, particularly in the morning
– Dizziness
– Shortness of breath
– Nosebleeds
– Visual disturbances
– Chest pain
 Diagnosis of Hypertension
Diagnosis involves measuring blood pressure using a sphygmomanometer. Multiple readings on different occasions are necessary to confirm hypertension. Additional diagnostic tests may include:
– Urinalysis: To check for kidney function and proteinuria.
– Blood Tests: To assess cholesterol levels, blood glucose, and kidney function.
– Electrocardiogram (ECG): To detect cardiac abnormalities.
– Echocardiogram: To assess heart structure and function.
– Ambulatory Blood Pressure Monitoring: To monitor blood pressure over 24 hours.
 Treatment of Hypertension
Treatment aims to lower blood pressure to reduce the risk of cardiovascular complications. It involves lifestyle modifications and pharmacotherapy.
Lifestyle Modifications
1. Diet:
– Adopt the DASH (Dietary Approaches to Stop Hypertension) diet, rich in fruits, vegetables, whole grains, and low-fat dairy.
– Reduce salt intake to less than 2,300 mg per day.
– Limit alcohol consumption.
2. Exercise:
– Engage in regular physical activity, such as 150 minutes of moderate-intensity aerobic exercise per week.
3. Weight Management:
– Achieve and maintain a healthy weight (BMI 18.5-24.9).
4. Smoking Cessation:
– Quit smoking to improve cardiovascular health.
5. Stress Management:
– Practice relaxation techniques like meditation, yoga, and deep breathing exercises.
 Pharmacotherapy of hypertension
1. Diuretics:
– Help the kidneys remove excess sodium and water, reducing blood volume.
– Examples: Hydrochlorothiazide, Furosemide.
2. ACE Inhibitors:
– Inhibit the RAAS, reducing vasoconstriction and blood volume.
– Examples: Enalapril, Lisinopril.
3. Angiotensin II Receptor Blockers (ARBs):
– Block the effects of angiotensin II, reducing blood pressure.
– Examples: Losartan, Valsartan.
4. Calcium Channel Blockers:
– Prevent calcium from entering heart and blood vessel cells, causing relaxation and reduced resistance.
– Examples: Amlodipine, Diltiazem.
5. Beta-Blockers:
– Reduce heart rate and cardiac output.
– Examples: Atenolol, Metoprolol.
6. Alpha-Blockers:
– Relax blood vessels by blocking alpha-adrenergic receptors.
– Examples: Doxazosin, Prazosin.
7. Centrally Acting Agents:
– Reduce sympathetic outflow from the central nervous system.
– Examples: Clonidine, Methyldopa.
 Prevention of Hypertension
Preventive measures include:
– Healthy Diet: Follow a balanced diet low in salt, saturated fats, and cholesterol.
– Regular Exercise: Maintain a regular physical activity routine.
– Weight Control: Maintain a healthy body weight.
– Limit Alcohol: Consume alcohol in moderation.
– Avoid Tobacco: Quit smoking and avoid exposure to secondhand smoke.
– Stress Management: Practice stress-reducing techniques.
Conclusion
Hypertension is a major health issue that significantly increases the risk of cardiovascular diseases. Early diagnosis and management through lifestyle modifications and pharmacotherapy are crucial for reducing morbidity and mortality associated with hypertension. Preventive strategies and public health interventions are essential for controlling the prevalence of hypertension and improving population health. Understanding the pathophysiology, symptoms, diagnosis, treatment, and prevention of hypertension is vital for effective management and improving patient outcomes.
