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🩺 HYPERTENSION — INTERNAL MEDICINE NOTES

Exam-Oriented | High-Yield | Made Easy

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📌 QUICK RECALL FRAMEWORK

BP = CO × TPR (Blood Pressure = Cardiac Output × Total Peripheral Resistance) All antihypertensives work by reducing CO and/or TPR.

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1. DEFINITION & CLASSIFICATION

ACC/AHA 2017 Guidelines (Most Current — Used in Exams)

Exam Pearl: If SBP and DBP fall in different categories → use the HIGHER category. (e.g., 162/92 = Stage 2, not Stage 1)

JNC 7 Classification (Older but Still Asked)

Mnemonic for JNC 7: 120/80 → 140/90 → 160/100 — each step is +20/+10

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2. EPIDEMIOLOGY — HIGH YIELD FACTS

• Affects 1/3 of adults worldwide
• Control rates in USA: < 50% (Global low/middle income: 8–14%)
• Black adults have highest prevalence and 2x higher CVD risk from HTN (REGARDS study)
• Most common cause of myocardial infarction, heart failure, AF, stroke, CKD, dementia
• After age 50 → SBP matters more than DBP (opposite of common belief - exam trap!)
• Hypertension contributes to:
  • 43% of coronary heart disease in Black adults
  • 22% of heart failure
  • 39% of strokes

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3. PATHOPHYSIOLOGY

Core Equation:

BP = CO × TPR
CO = HR × SV

Key Mechanisms of HTN:

Pressure Natriuresis - Key Concept:

• Kidneys normally respond to ↑ BP by excreting more Na⁺ (reset mechanism)
• In HTN → this curve is shifted RIGHT (more pressure needed to excrete same Na⁺)
• Reduced RAAS responsiveness makes BP salt-sensitive

Pulse Pressure = SBP − DBP

• ↑ Pulse pressure = marker of vascular stiffness
• Seen in elderly, females, diabetes
• SBP is the stronger predictor of long-term CVD mortality than DBP or pulse pressure alone

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4. ETIOLOGY

Primary (Essential) HTN — 90–95% of cases

• No identifiable cause
• Risk factors: obesity, high sodium diet, sedentary lifestyle, alcohol, family history, age, Black race

Secondary HTN — 5–10% of cases

Mnemonic: "PRCHADS" = Primary aldosteronism, Renovascular, Cushing's, Hypothyroid/Hyperthyroid, Aortic coarctation, Drugs, Sleep apnea

Exam Pearl: Suspect secondary HTN when: onset < 30 yrs, resistant HTN, hypokalemia without diuretics, abrupt BP worsening, or BP refractory to ≥ 3 drugs.

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5. DIAGNOSIS & BP MEASUREMENT

Proper Office BP Measurement (Box MUST KNOW):

1. Patient seated quietly for ≥ 5 minutes
2. Back supported, feet flat on floor
3. Arm at heart level, bare arm
4. Cuff covers 80% of arm circumference
5. Average ≥ 2 readings on ≥ 2 occasions
6. Use Korotkoff Phase V (disappearance) for diastolic

Types of BP Monitoring:

White Coat HTN = High office BP + normal ABPM → treat with lifestyle, no drugs initially Masked HTN = Normal office + high ABPM → higher CV risk, treat!

Workup for New HTN:

• Basic labs: FBS, lipid profile, serum creatinine, eGFR, urine ACR, electrolytes, CBC
• ECG: LVH (Sokolow-Lyon: S in V1 + R in V5/V6 > 35mm)
• Echo: if suspected LVH or heart failure
• Fundoscopy: Keith-Wagener-Barker grading

Keith-Wagener-Barker Retinopathy:

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6. TARGET ORGAN DAMAGE (TOD)

Mnemonic: "BRAIN-K" = Brain, Retina, Aorta (heart), In the kidney (nephropathy)

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7. TREATMENT

Step 1: Lifestyle Modifications (ALL patients)

Mnemonic: "DASH-WAS"

When to Start Drugs?

BP Targets:

ACCORD Trial: In diabetics, targeting < 120/80 vs < 140/90 - no difference in primary CV outcomes, but MORE side effects and reduced strokes only. So aggressive targets not universally recommended.

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8. ANTIHYPERTENSIVE DRUG THERAPY

First-Line Drug Classes (4 pillars):

Mnemonic: "A-B-C-D" (modified) A = ACE inhibitors/ARBs C = Calcium Channel Blockers (CCBs) D = Diuretics (Thiazide type - Chlorthalidone preferred) B = Beta-blockers (NOT first line in uncomplicated HTN)

Drug Class Summary:

Best Combination Therapy:

• ACEi + CCB (Amlodipine) = Best combination per ACCOMPLISH trial
• ACEi + Thiazide = Also acceptable
• NEVER combine: ACEi + ARB, or ARB + Renin inhibitor (dual RAAS blockade = dangerous)
• If BP > 20/10 above target → start with 2-drug combination directly

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9. COMPELLING INDICATIONS (JNC 7 Table — Very High Yield)

Exam Tips:

• Black patients: CCB or Thiazide preferred first line (ACEi/ARB less effective as monotherapy)
• Pregnancy: Methyldopa (1st choice), Labetalol, Nifedipine. AVOID ACEi, ARBs, Aliskiren.
• Asthma/COPD: Avoid BB. Use CCB.
• Gout: Avoid Thiazides. Use Losartan (uricosuric property - bonus!).
• BPH + HTN: Alpha-blocker (Doxazosin).
• Raynaud's + HTN: CCB (Nifedipine).

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10. RESISTANT HYPERTENSION

Definition:

Causes to Rule Out First ("Pseudo-resistant"):

1. Poor medication adherence (MCC!)
2. White coat effect
3. Suboptimal technique
4. Volume overload (under-diuresis)
5. Drug interactions (NSAIDs, OCPs, decongestants, cocaine, licorice, erythropoietin, cyclosporine)

Truly Resistant - Look For Secondary Causes:

Mnemonic: "PRCHADS" (same as secondary HTN above)

• Primary aldosteronism (#1)
• CKD
• OSA
• Pheochromocytoma
• Cushing's syndrome
• Renal artery stenosis
• Coarctation of aorta

Management of Resistant HTN:

1. Optimize existing 3-drug regimen
2. Add Spironolactone 25–50 mg/day (evidence-based, highly effective - PATHWAY-2 trial)
3. Screen for secondary causes
4. Consider referral to HTN specialist
5. Renal denervation (investigational - modest BP reduction, not FDA approved)

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11. HYPERTENSIVE CRISIS

Definitions:

Remember: Urgency = 1% of ER visits. Emergency = 0.3% of ER visits. Most patients = exacerbation of previously diagnosed but poorly controlled HTN.

Hypertensive Emergency - Target Organ Damage Presentations:

BP Reduction Strategy (General Rule):

• First 1–2 hours: Reduce MAP by 10–15%
• Next 12–24 hours: Another 10–15% reduction
• Exception (faster reduction): Aortic dissection, cardiogenic pulmonary edema, ACS, hemorrhagic stroke

IV Drugs for Hypertensive Emergency:

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12. SPECIAL SITUATIONS

HTN in Pregnancy:

Drug of choice in pregnancy = Methyldopa AVOID: ACEi, ARBs (teratogenic - fetal renal dysgenesis)

HTN in CKD:

• Target < 130/80 mmHg
• ACEi or ARB preferred (reduce proteinuria, slow progression)
• Thiazides lose efficacy at eGFR < 30 → switch to loop diuretics
• Monitor K⁺ and creatinine after starting ACEi/ARB

HTN in Elderly:

• Isolated Systolic HTN (ISH) = most common pattern
• Treat cautiously (orthostasis risk)
• JNC 8 allows < 150/90 for age > 60 (controversial)
• Chlorthalidone, CCBs preferred

HTN in Diabetes:

• Target < 130/80 mmHg
• ACEi or ARB first line (nephroprotective)
• CCBs or thiazides as add-on

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13. EXAM MNEMONICS RAPID RECALL

"ABCD" of 1st line antihypertensives:

"5 P's" of Pheo:

Secondary HTN "PRCHADS":

Hypertensive Emergency target organs "BRAIN-K":

Cough from ACEi = bradykinin buildup → Switch to ARB (no cough)

Rebound HTN on abrupt withdrawal = Clonidine (also BB in IHD)

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14. HIGH-YIELD CLINICAL PEARLS - EXAM TRAPS ⚠️

1. SBP > DBP as predictor after age 50 - examiners love to flip this.
2. Chlorthalidone > HCTZ (longer acting, better outcomes in ALLHAT) - use chlorthalidone when they say "best thiazide."
3. ACEi + ARB combination = CONTRAINDICATED (dual RAAS blockade - worsens renal outcomes).
4. Never give BB alone in pheo - causes paradoxical hypertension from unopposed α stimulation.
5. Aortic dissection = most aggressive BP reduction of all emergencies (SBP < 120 within minutes).
6. Ischemic stroke: Do NOT aggressively lower BP (lose autoregulation in penumbra). Only lower if > 220/120 (no thrombolytics) or > 185/110 (with thrombolytics).
7. ACCOMPLISH trial = ACEi + CCB superior to ACEi + Thiazide in reducing CV events.
8. ALLHAT trial = Chlorthalidone as effective as CCB or ACEi; reduced HF more.
9. Losartan has a uricosuric effect - best ARB in patient with HTN + gout.
10. Methyldopa = DOC in pregnancy; causes Coombs positive hemolytic anemia (side effect).
11. Spironolactone for resistant HTN = highly effective (PATHWAY-2 trial).
12. Hydralazine = DOC for HTN in pregnancy emergencies (IV), also causes lupus-like syndrome at high doses.

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15. QUICK REVISION FLOWCHART

NEW HTN DIAGNOSED
       ↓
Measure BP properly (avg ≥2 readings on ≥2 visits)
       ↓
Rule out White Coat HTN (ABPM if needed)
       ↓
Lifestyle modifications for ALL
       ↓
Drug therapy?
→ Stage 1 + 10-yr ASCVD < 10% → Lifestyle only
→ Stage 1 + 10-yr ASCVD ≥ 10% → Add drug
→ Stage 2 (≥ 140/90) → Drug + Lifestyle
       ↓
Choose drug based on compelling indication
(ACEi/ARB + CCB/Thiazide as first combo)
       ↓
Target < 130/80 (most patients)
       ↓
Not at goal after 4–6 weeks?
→ Increase dose OR Add second drug
       ↓
Resistant? (≥ 3 drugs, including diuretic)
→ Add Spironolactone
→ Screen for secondary causes
→ Refer to specialist

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