Hypertension and Hypertensive Emergencies

Definition & Classification - Pressure Cooker Intro

Hypertension (HTN): Persistent elevation of systemic arterial blood pressure (BP).

• ACC/AHA 2017 Classification:
  • Normal: <120/<80 mmHg
  • Elevated: 120-129/<80 mmHg
  • Stage 1: 130-139 or 80-89 mmHg
  • Stage 2: ≥140 or ≥90 mmHg
• JNC8 / IGH-IV (2019): Define HTN as BP ≥140/≥90 mmHg. IGH-IV further classifies: Optimal, Normal, High-Normal, Grades 1-3.

⭐ Most common type of hypertension is Essential (Primary) Hypertension (~90-95% cases).

Etiology & Risk Factors - The Usual Suspects

• Primary HTN (Essential): ~90-95% cases. Multifactorial.
  • Risk Factors:
    • Non-modifiable: Age, Family Hx, Ethnicity (African ancestry)
    • Modifiable: ↑Salt, Obesity (BMI >30), Alcohol, Smoking, Sedentary, Stress, DM, Dyslipidemia
• Secondary HTN: ~5-10% cases. Identifiable cause.
  • Common Causes:
    • Renal: CKD, RAS
    • Endocrine: Conn's, Cushing's, Pheo, Thyroid/Parathyroid
    • Drugs: NSAIDs, OCPs, Steroids, Decongestants
    • Other: OSA, Coarctation of Aorta

⭐ Renal artery stenosis is a common correctable cause of secondary hypertension.

Pathophysiology & Complications - Body Under Siege

• Pathophysiology:
  • ↑RAAS: Ang II & Aldo → $Na⁺/H₂O$ retention, vasoconstriction.
  • ↑Sympathetic Nervous System (SNS) activity: ↑HR, ↑CO, ↑PVR.
  • Endothelial dysfunction: ↓NO, ↑ET-1.
  • Vascular remodeling: Arterial stiffness, luminal narrowing.
• Complications (Target Organ Damage - TOD):
  • Heart: LVH, HF, CAD.
  • Brain: Stroke, Hypertensive Encephalopathy, dementia.
  • Kidneys: Nephrosclerosis, CKD (proteinuria).
  • Eyes: Hypertensive Retinopathy (KWB Grades I-IV).
  • Vasculature: Aortic dissection, PAD.

⭐ LVH is an early cardiac complication, significantly increasing cardiovascular risk.

Diagnosis & Evaluation - Case Unfolding

• Accurate BP: Averaged readings (2-3 visits or ABPM/HBPM). Standardized technique crucial.
• ABPM/HBPM: For white-coat, masked, or nocturnal HTN.
• Assess: CV risk factors, Target Organ Damage (TOD).
• Investigations:
  • Baseline: ECG, urine routine, K+, creatinine, fasting glucose, lipid profile.
  • TOD screen: Fundoscopy, Echo (LVH), urine ACR.

⭐ Resistant HTN or HTN in young (<30 yrs) warrants workup for secondary causes.

Chronic HTN Management - Chill Pill Plan

• Foundation: Lifestyle (DASH diet, ↓Na <2.3g/day, aerobic exercise, weight loss, ↓alcohol).
• Pills (📌 "ACD" choices):
  • A: ACEi (Ramipril)/ARB (Telmisartan)
  • C: CCB (Amlodipine, Nifedipine)
  • D: Diuretics (Thiazides: Chlorthalidone, HCTZ)
• Plan:

\*Target <**130/80** mmHg if high ASCVD risk, DM, CKD.

• Pregnancy Safe: Labetalol, Nifedipine, Methyldopa. (📌 "Hypertensive Moms Love Nifedipine")

⭐ ACE inhibitors & ARBs are contraindicated in pregnancy due to teratogenicity.

Hypertensive Crises - Code Red Pressure

• Hypertensive Urgency: SBP >180 mmHg or DBP >120 mmHg, NO Target Organ Damage (TOD).
• Hypertensive Emergency: SBP >180 mmHg or DBP >120 mmHg, WITH acute TOD.
  • Examples: Encephalopathy, MI, unstable angina, LVF, aortic dissection, eclampsia, severe pre-eclampsia.
• Management (Emergency): ICU admission, IV antihypertensives.
  • Goal: ↓MAP by 10-20% in first hour, then gradually by 5-15% over next 23 hours.
  • Exceptions: Aortic dissection (rapid ↓SBP to <120 mmHg in 20 min), acute ischemic stroke (permissive hypertension).
• Key IV Drugs: Labetalol, Nicardipine, Sodium Nitroprusside (SNP), Nitroglycerin (NTG).

⭐ In hypertensive emergency with aortic dissection, rapidly lower SBP to <120 mmHg and HR to <60 bpm within 5-10 minutes using IV beta-blockers (e.g., esmolol, labetalol) first, then vasodilators if needed (e.g., nitroprusside).

High‑Yield Points - ⚡ Biggest Takeaways

• Hypertensive emergency: Severe HTN with acute end-organ damage (brain, heart, kidney).
• Lower MAP by 10-20% in 1st hour, then 5-15% over next 23 hrs in emergencies.
• Labetalol, Nicardipine are key IV agents; Nitroprusside for rapid control (cyanide risk).
• Common secondary HTN causes: Renal artery stenosis, Conn's, pheochromocytoma.
• Resistant HTN: BP uncontrolled on ≥3 drugs (including diuretic).
• Permissive HTN in acute ischemic stroke (up to 220/120 mmHg if no thrombolysis).