Hypertension Study Guide

📖 Core Concepts Hypertension – chronic elevation of arterial pressure (≥ 130/80 mmHg or 140/90 mmHg depending on guideline). Primary (essential) hypertension – 90‑95 % of cases; no single identifiable cause, driven by lifestyle & genetics. Secondary hypertension – 5‑10 % of cases; due to a specific disorder (e.g., renal disease, endocrine tumors, drugs). Hypertensive crisis – systolic ≥ 180 mmHg or diastolic ≥ 120 mmHg. Urgency: no acute organ damage → oral meds, 24–48 h. Emergency: organ damage (brain, heart, kidney, lung) → rapid IV therapy. Blood‑pressure measurement – office, ambulatory (12‑24 h) and home monitoring; ABPM is gold‑standard for confirmation. Target BP – generally < 140/90 mmHg; < 150/90 mmHg for many adults ≥ 60 y; lower targets for diabetes, CKD, high CV risk. --- 📌 Must Remember Prevalence – 33 % of world adults; 1/3 of U.S. adults (≥ 46 % after 2017 guideline change). Risk factors – excess Na⁺, obesity (BMI ≥ 25 kg/m²), smoking, inactivity, alcohol (> 1 drink/d women, > 2 drinks/d men). Primary vs secondary proportion – 90‑95 % primary, 5‑10 % secondary. Diagnostic thresholds – ≥ 130/80 mmHg (ACC/AHA) or ≥ 140/90 mmHg (ESC/ESH) persistently. First‑line drug classes – thiazide‑type diuretics, calcium‑channel blockers (CCB), ACE inhibitors (ACEI), angiotensin‑II receptor blockers (ARB). Resistant hypertension – BP above target despite ≥ 3 agents of different classes (including a diuretic) at optimal doses. Refractory hypertension – uncontrolled BP despite ≥ 5 agents. Lifestyle impact – DASH diet ↓ SBP 8‑14 mmHg; ↓ Na⁺ 2 g/d ↓ SBP ≈ 2 mmHg; 5 % weight loss ↓ SBP ≈ 5 mmHg; 150 min/week aerobic exercise ↓ SBP 4‑9 mmHg. --- 🔄 Key Processes Screening & Diagnosis Measure BP (proper cuff, seated, 5 min rest). Confirm elevated reading on ≥ 2 separate visits or use ABPM/HBPM. For children, compare to sex‑age‑height percentiles; hypertension ≥ 95th percentile on ≥ 3 occasions. Initial Work‑up Labs: serum electrolytes, creatinine, eGFR, lipid panel, HbA1c/fasting glucose, urine protein dipstick. ECG to assess LV hypertrophy or ischemia. Management Algorithm Step 1: Lifestyle modification (DASH, ↓ Na⁺, weight loss, exercise, limit alcohol, stop smoking). Step 2: Initiate 1‑2 first‑line agents (prefer combination if SBP ≥ 20 mmHg above goal). Step 3: Titrate dose; add a third class if target not reached. Step 4: Evaluate for resistant hypertension → adherence check, ABPM, rule out secondary causes, consider MR antagonist (spironolactone). Hypertensive Emergency Treatment Immediate IV antihypertensives (e.g., labetalol, nicardipine). Reduce MAP by ≤ 25 % within the first hour, then to target over next 24 h. --- 🔍 Key Comparisons Primary vs Secondary Hypertension Primary: no identifiable cause; lifestyle/genetic; majority of cases. Secondary: specific cause (renal, endocrine, drugs, sleep apnea); 5‑10 % of cases. Hypertensive Urgency vs Emergency Urgency: SBP ≥ 180 mmHg or DBP ≥ 120 mmHg without acute organ damage; oral meds. Emergency: Same pressures with end‑organ damage; IV meds, rapid reduction. Thiazide Diuretic vs Loop Diuretic (first‑line) Thiazide: preferred for uncomplicated hypertension; long‑acting, inexpensive. Loop: reserved for CKD < 30 mL/min, heart failure, or resistant cases. ACEI vs ARB ACEI: may cause cough; first‑line. ARB: similar efficacy; used if ACEI intolerant. Never combine ACEI + ARB. --- ⚠️ Common Misunderstandings “Hypertension always causes headaches.” – Most patients are asymptomatic; headache is not a reliable indicator. “If BP is 150/95 mmHg, medication is always required.” – Lifestyle changes may suffice, especially if < 160/100 mmHg and low CV risk. “Beta‑blockers are first‑line for everyone.” – They are less effective for primary prevention of CV events; reserved for CAD, HF, or specific indications. “White‑coat hypertension is harmless.” – Can progress to true hypertension; ABPM/HBPM needed to differentiate. --- 🧠 Mental Models / Intuition “Pressure = Flow × Resistance.” In primary hypertension, ↑ total peripheral resistance (not cardiac output) is the main driver. “The salt‑sensitivity ladder.” More dietary Na⁺ → ↑ extracellular volume → ↑ cardiac output → chronic vascular remodeling → ↑ resistance. “Target‑organ damage is the alarm system.” When you start seeing retinopathy, albuminuria, or LVH, the disease has moved from “silent” to “dangerous.” --- 🚩 Exceptions & Edge Cases Isolated systolic hypertension – common in older adults due to arterial stiffening; DBP may be normal. Pregnancy – gestational hypertension vs pre‑eclampsia (adds proteinuria/organ dysfunction); eclampsia = seizures → emergency. Children – hypertension defined by percentiles, not absolute numbers. Very low BP targets (< 110 mmHg SBP) – marginal benefit, higher risk of hypotension, especially in frail elders. --- 📍 When to Use Which | Clinical Situation | Preferred First‑Line Drug(s) | Rationale | |--------------------|------------------------------|-----------| | Young, low‑risk adult | Thiazide diuretic or CCB | Proven efficacy, low cost | | Black patients | CCB or thiazide | Better BP response than ACEI/ARB alone | | Diabetes or CKD (proteinuria) | ACEI or ARB | Renoprotective, ↓ albuminuria | | History of myocardial infarction | Beta‑blocker + ACEI/ARB | Improves survival, reduces remodeling | | Contraindication to ACEI (cough) | ARB | Same renin‑angiotensin blockade without cough | | Resistant hypertension | Add spironolactone (MRA) after confirming adherence | Targets aldosterone‑mediated sodium retention | | Pregnancy | Methyldopa, labetalol, nifedipine | Safe for fetus; ACEI/ARBs are teratogenic | --- 👀 Patterns to Recognize “High SBP + normal DBP in older adults → think isolated systolic hypertension (arterial stiffness). “Sudden rise in BP + acute neurologic/renal/respiratory signs → hypertensive emergency. “BP spikes in clinic but normal at home → possible white‑coat effect; order ABPM/HBPM. “Refractory hypertension + hypokalemia → suspect primary aldosteronism. “Elevated BP + nocturnal non‑dipping on ABPM → higher CV risk, consider sleep apnea work‑up. --- 🗂️ Exam Traps Trap: “All patients with BP ≥ 140/90 mmHg need immediate medication.” Why tempting: Classic textbook threshold. Why wrong: Guidelines allow lifestyle trial for modest elevations, especially if < 160/100 mmHg and low risk. Trap: “Beta‑blockers are first‑line for everyone.” Why tempting: Historically taught as a main class. Why wrong: Evidence shows they are less effective for primary prevention; reserved for specific comorbidities. Trap: “ACEI and ARB can be combined for additive effect.” Why tempting: Both block the renin‑angiotensin system. Why wrong: Combination raises risk of hyperkalemia, renal failure, and offers no extra BP benefit. Trap: “A single office BP reading > 180/120 mmHg automatically means hypertensive emergency.” Why tempting: Numbers match crisis definition. Why wrong: Must have evidence of acute target‑organ damage; otherwise it’s a hypertensive urgency. Trap: “In children, hypertension is defined as > 130/80 mmHg just like adults.” Why tempting: Simpler to remember. Why wrong: Pediatric diagnosis uses age‑sex‑height percentiles (≥ 95th percentile). ---