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Hypertensive emergencies

Hypertensive emergencies

Hypertensive emergencies

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Diagnosis - Pressure Cooker Crisis

Defined as severe hypertension (SBP >180 mmHg or DBP >120 mmHg) with evidence of acute end-organ damage. The key is active, ongoing injury.

  • Key End-Organ Damage:
    • Brain: Encephalopathy, Stroke (ICH)
    • Eyes: Papilledema
    • Heart: Acute Coronary Syndrome (ACS), Heart Failure
    • Vessels: Aortic Dissection
    • Kidney: Acute Kidney Injury (AKI)
    • Pregnancy: Eclampsia

Fundoscopy showing hypertensive retinopathy with papilledema

⭐ Differentiating from hypertensive urgency is critical; urgency lacks acute end-organ damage and is managed with oral agents, not IV infusions.

Initial Management - Dropping The Pressure

  • Initial Goal: Lower Mean Arterial Pressure (MAP) by 10-20% in the first hour.
  • Subsequent Goal: Gradually reduce BP by another 5-15% over the next 23 hours.
  • $MAP = DP + 1/3(SP - DP)$
  • ⚠️ Crucial: Avoid precipitous drops in BP, which can cause ischemia (CVA, MI, AKI).

Exception: In acute aortic dissection, rapidly lower SBP to <120 mmHg and HR to <60 bpm within 20 minutes.

Condition-Specific Goals - When Organs Cry Out

Tailoring BP reduction is critical based on the specific end-organ damaged. The goal is controlled lowering, not normalization, to avoid iatrogenic hypoperfusion. A general rule is to decrease Mean Arterial Pressure (MAP) by no more than 10-20% in the first hour.

ConditionTarget BP / Rate of LoweringPreferred Agent(s)Agents to AVOID
Aortic DissectionRapidly ↓ SBP to <120 mmHg & HR <60Esmolol, Labetalol (β-blocker first!)Vasodilators alone (e.g., Hydralazine)
Acute Ischemic StrokePermissive HTN unless >220/120 mmHgLabetalol, NicardipineAggressive lowering
(tPA candidate: <185/110 mmHg)
ACS / MI↓ SBP by 10-20% (symptom relief)Nitroglycerin, LabetalolHydralazine, Nitroprusside (coronary steal)
Hypertensive Encephalopathy↓ MAP by 20-25% over hoursNicardipine, LabetalolRapid, excessive lowering
Acute Pulmonary Edema↓ Preload & AfterloadNitroglycerin, FurosemideBeta-blockers (if decompensated HF)

IV Drug Reference - The Vasoactive Arsenal

  • 📌 Mnemonic: 'Lovely Nice Evening Nitro' (Labetalol, Nicardipine, Esmolol, Nitroprusside/Nitroglycerin).
DrugMechanismOnset/DurationKey Considerations
Labetalolβ₁/β₂/α₁ Blocker2-5 min / 2-4 hrAvoid in asthma/COPD, bradycardia, heart failure.
NicardipineDihydropyridine CCB5-10 min / 1-4 hrPotent vasodilator; reflex tachycardia possible.
EsmololSelective β₁ Blocker1-2 min / 10-20 minUseful in aortic dissection, tachyarrhythmias.
NitroprussideArterial/Venous Dilator<1 min / 2-3 min⚠️ Risk of cyanide toxicity (esp. w/ renal failure).
NitroglycerinVenodilator > Arterial1-3 min / 5-10 minBest for ACS, pulmonary edema; avoid in PDE5i use.

High‑Yield Points - ⚡ Biggest Takeaways

  • A hypertensive emergency is severe hypertension (>180/120 mmHg) with evidence of acute end-organ damage.
  • The initial goal is to lower Mean Arterial Pressure (MAP) by 10-20% in the first hour and by another 5-15% over the next 23 hours.
  • Avoid rapid, excessive BP reduction to prevent cerebral, coronary, or renal ischemia.
  • Management requires IV antihypertensive agents; oral agents are for hypertensive urgency.
  • Exceptions include aortic dissection (rapidly lower SBP to <120 mmHg) and acute ischemic stroke (permissive hypertension).

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