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Everything About Hypertension - In Simple Words

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1. What Is Blood Pressure?

• The top number (systolic) = pressure when your heart beats and pushes blood out
• The bottom number (diastolic) = pressure when your heart rests between beats

• Cardiac output - how much blood your heart pumps per minute (depends on heart rate and how forcefully it beats)
• Peripheral resistance - how narrow or stiff your blood vessels are (narrower = more resistance = higher pressure)

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2. What Is Hypertension?

Blood Pressure Categories (2025 AHA/ACC Guidelines)

Note: In 2025, the AHA/ACC updated their guidelines using a new risk calculator (called PREVENT) that looks at 10-year AND 30-year cardiovascular risk to decide when to start treatment.

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3. How Common Is Hypertension?

• Only about half of people with high BP know they have it
• Of those who know, only half are treated
• Of those treated, only half are properly controlled

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4. Types of Hypertension

Type 1: Primary (Essential) Hypertension

• Most common - accounts for 90-95% of all cases
• No single clear cause found
• Caused by a combination of genetics, lifestyle, and environment
• "In 90% to 95% of adults with hypertension, the cause is unknown" - Comprehensive Clinical Nephrology

Type 2: Secondary Hypertension

• Caused by another specific disease (only about 5-10% of cases)
• Once you treat that disease, BP often improves

• Kidney diseases - chronic glomerulonephritis, renal artery stenosis (narrowing of the kidney artery)
• Hormonal problems:
  • Primary aldosteronism (adrenal gland makes too much aldosterone hormone)
  • Pheochromocytoma (a tumor in the adrenal gland)
  • Cushing syndrome (too much cortisol)
  • Thyroid disease
• Sleep apnea (breathing stops during sleep)
• Narrowing of the aorta (coarctation of the aorta) - more common in children
• Certain medications - birth control pills, NSAIDs (like ibuprofen), steroids, decongestants

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5. What Causes Primary (Essential) Hypertension?

Lifestyle Factors

• Eating too much salt - salt makes your body hold water, raising blood volume and pressure
• Being overweight/obese - obesity alone accounts for 65-75% of primary hypertension risk
• Not exercising enough (sedentary lifestyle)
• Drinking too much alcohol
• Not eating enough potassium (potassium helps relax blood vessels)
• Smoking
• Chronic stress

Medical Factors

• Insulin resistance and diabetes - high insulin damages blood vessel walls
• High sodium intake - kidneys hold onto more sodium and water
• The Renin-Angiotensin-Aldosterone System (RAAS) becoming overactive - this is a hormonal system that regulates how much water your kidneys keep. When overactive, it raises BP.

Genetic Factors

• Hypertension runs in families
• However, no single "hypertension gene" has been found - it's a complex mix of many gene variations plus environmental triggers

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6. Symptoms - The "Silent Killer"

• Headaches (especially at the back of the head, in the morning)
• Dizziness
• Blurred vision
• Shortness of breath
• Chest pain
• Nosebleeds
• Fatigue

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7. How Is Blood Pressure Measured?

• Sit quietly for 5 minutes before measurement
• Sit with your back supported, feet flat on the floor
• The cuff should be on your bare upper arm, at heart level
• Do NOT smoke, exercise, or have caffeine 30 minutes before
• Measure at least 2-3 times and take the average
• Measure on the same arm each time

• Office BP - measured by your doctor
• Home BP monitoring (HBPM) - you measure at home with your own device (the 2025 guidelines now emphasize this strongly)
• Ambulatory BP monitoring (ABPM) - a device you wear for 24 hours to get readings throughout the day and night - this is the most accurate method

The 2025 AHA/ACC guidelines now say that home and ambulatory BP monitoring should be central to diagnosis and management, not just supplements to office readings.

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8. What Happens to Your Body With Hypertension?

Heart

• The heart has to work harder to pump against high pressure
• The heart muscle gets thicker (left ventricular hypertrophy)
• This leads to heart failure (the heart gets too weak or too stiff to pump properly)
• Coronary artery disease and heart attack (myocardial infarction)

Brain

• Damaged arteries can burst: hemorrhagic stroke (bleeding in the brain)
• Blood clots form more easily in damaged arteries: ischemic stroke (blockage)
• Over time: dementia and cognitive decline

Kidneys

• High pressure damages the tiny filtering units in the kidney (glomeruli)
• Leads to chronic kidney disease (CKD)
• Eventually kidney failure requiring dialysis

Eyes

• Damaged blood vessels in the retina: hypertensive retinopathy
• Can cause blurred vision or even blindness

Blood Vessels

• Arteries throughout the body become stiff and narrow (atherosclerosis)
• Peripheral artery disease (poor circulation in legs)
• Aortic dissection (a life-threatening tear in the main artery) - Morgan & Mikhail's Clinical Anesthesiology

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9. Hypertensive Emergencies

• Chest pain (heart attack or aortic dissection)
• Shortness of breath (heart failure)
• Confusion or stroke symptoms
• Vision loss
• Kidney failure (less urine output)

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10. Hypertension in Special Groups

In Pregnancy

• Gestational hypertension - high BP after 20 weeks, no protein in urine
• Preeclampsia - high BP after 20 weeks + protein in urine, or signs of organ damage
  • Dangerous to both mother and baby
  • Can cause seizures (eclampsia) - a life-threatening emergency
  • Treatment with magnesium sulfate to prevent seizures; medications like labetalol or nifedipine to lower BP
  • Delivery of the baby is the definitive cure

In Elderly

• "Isolated systolic hypertension" is common (top number is high, bottom number is normal)
• Goal BP is still <130/80 but must be careful not to lower BP too much (risk of falls and dizziness)

In Diabetes

• Hypertension + diabetes greatly multiplies the risk of kidney and heart disease
• ACE inhibitors or ARBs are preferred because they protect the kidneys

In Chronic Kidney Disease (CKD)

• Both hypertension causes CKD and CKD causes hypertension - a vicious cycle
• ACE inhibitors or ARBs are first-line to slow kidney damage

In Children

• Often secondary to kidney disease or coarctation of the aorta
• Lifestyle changes are the first step

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11. Diagnosis - How Doctors Confirm Hypertension

1. Measure BP on at least 2 separate visits
2. Rule out secondary causes if:
   • Young patient
   • Resistant to multiple medications
   • Sudden onset
   • Low potassium (hypokalemia) - suggests aldosteronism
3. Blood tests: kidney function, electrolytes, blood sugar, cholesterol, thyroid
4. Urine test: for protein (sign of kidney damage)
5. ECG: to check if heart is already enlarged
6. Echocardiogram: to see heart size and function
7. Eye exam (fundoscopy): to see if retinal vessels are damaged

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12. Treatment: Lifestyle Changes First

The DASH Diet

• Eat more: fruits, vegetables, whole grains, low-fat dairy, nuts, seeds
• Eat less: salt (sodium), red meat, sugar, processed food, saturated fats
• Can lower BP by 8-14 mm Hg

Reduce Salt Intake

• Limit sodium to less than 2.3 grams per day (about 1 teaspoon of salt)
• The 2025 guidelines now also recommend salt substitutes (potassium chloride instead of sodium chloride) as an evidence-based strategy

Exercise

• At least 30 minutes of moderate-intensity aerobic exercise most days (walking, cycling, swimming)
• Can lower BP by 4-9 mm Hg

Weight Loss

• Losing even 5-10 kg (10-20 lbs) can significantly lower BP
• Every 1 kg of weight lost = approximately 1 mm Hg drop in systolic BP

Quit Smoking

• Smoking damages blood vessel walls and raises BP acutely
• Stopping protects the heart and vessels

Limit Alcohol

• Men: no more than 2 drinks per day
• Women: no more than 1 drink per day

Stress Reduction

• Relaxation techniques, adequate sleep, mindfulness

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13. Treatment: Medications

The 4 Main First-Line Drug Classes

1. Thiazide Diuretics (Water Pills)

• Examples: Hydrochlorothiazide, Chlorthalidone
• How they work: Make your kidneys remove more salt and water, so blood volume decreases. After a few weeks, they also relax blood vessel walls.
• Good for: Most patients, especially elderly and African Americans
• Side effects: Low potassium (hypokalemia), high uric acid (can trigger gout), slightly raised blood sugar

2. ACE Inhibitors

• Examples: Lisinopril, Enalapril, Ramipril, Captopril
• How they work: Block a key enzyme (ACE) that converts angiotensin I to angiotensin II. Angiotensin II normally raises BP by narrowing blood vessels and increasing water retention. By blocking it, vessels relax and BP drops.
• Good for: People with diabetes, heart failure, chronic kidney disease
• Side effects: Dry persistent cough (in up to 10% of patients), high potassium, angioedema (rare but dangerous swelling of lips/throat), cannot be used in pregnancy

3. Angiotensin Receptor Blockers (ARBs)

• Examples: Losartan, Irbesartan, Valsartan, Olmesartan
• How they work: Similar to ACE inhibitors but block the receptor where angiotensin II acts (AT1 receptor). Lower BP by relaxing blood vessels and reducing water retention.
• Good for: Same as ACE inhibitors; preferred when ACE inhibitors cause a cough
• Side effects: Similar to ACE inhibitors but without the cough; still cannot be used in pregnancy

4. Calcium Channel Blockers (CCBs)

• Examples: Amlodipine, Nifedipine (dihydropyridines); Verapamil, Diltiazem (non-dihydropyridines)
• How they work: Calcium makes blood vessel muscle cells contract. By blocking calcium channels, the vessels relax and widen, lowering pressure.
• Good for: Elderly, African Americans, patients with angina (chest pain from heart)
• Side effects: Ankle swelling, flushing, headache; non-dihydropyridines (verapamil, diltiazem) can slow the heart

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Other Drug Classes

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Drug Choice Based on Other Conditions

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When to Use More Than One Drug

• If BP is more than 20/10 mm Hg above target, start with TWO drugs at once
• Most people with hypertension need 2 or more drugs to reach their BP goal
• Fixed-dose combination pills (two drugs in one tablet) make this easier and improve compliance

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14. Resistant Hypertension

• Not taking medications properly (poor adherence)
• Too much salt in diet
• Secondary cause not treated (e.g., undiagnosed sleep apnea or aldosteronism)
• Interactions with other medications (NSAIDs, birth control pills, steroids)

• Add spironolactone (very effective)
• Renal denervation - a new procedure (catheter-based) that cuts the nerve supply to the kidneys. The 2025 AHA/ACC guidelines introduced this as a Class IIb option (can be used with shared decision-making).

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15. Monitoring and Follow-Up

• Check BP regularly (home monitoring every day or at least weekly)
• Blood tests every 3-6 months to check kidneys, potassium, and blood sugar
• Annual eye exam
• ECG or echo if needed
• Keep taking your medications even when you feel well - hypertension has no symptoms but still causes damage silently

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16. Can Hypertension Be Prevented?

• Healthy weight from childhood
• Low-salt, high-potassium diet
• Regular exercise
• No smoking
• Limited alcohol
• Stress management
• Regular BP checks from age 18 onward

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17. Quick Summary Table

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• Harrison's Principles of Internal Medicine, 22nd Ed. (2025), Chapter 288 on Hypertension
• Lippincott Illustrated Reviews: Pharmacology - Antihypertensive Drugs Chapter
• Fuster and Hurst's The Heart, 15th Ed. - Pathophysiology of Primary Hypertension
• Goldman-Cecil Medicine - Drug-Resistant Hypertension
• Comprehensive Clinical Nephrology, 7th Ed. - Classification by Cause
• Park's Textbook of Preventive and Social Medicine - Hypertension Epidemiology
• 2025 AHA/ACC Hypertension Guideline - Updated BP classification and treatment thresholds