ICU · Cardiovascular
Hypertensive emergency and crisis
Also known as Hypertensive emergency · Malignant hypertension · Hypertensive encephalopathy · Pre-eclampsia and eclampsia · Phaeochromocytoma crisis
Hypertensive emergency = severe BP elevation (typically 180/120) with ACUTE end-organ damage (encephalopathy, stroke, MI, pulmonary oedema, aortic dissection, AKI, pre-eclampsia/eclampsia). Requires IMMEDIATE IV treatment in ICU (arterial line, titratable agents). Goal: reduce MAP by 10-20% in first hour, then to 160/100 within 2-6h. Do NOT reduce BP too rapidly — risk of hypoperfusion (especially brain — cerebral autoregulation is shifted right in chronic HTN). Agents: labetalol (versatile — most emergencies), nicardipine (smooth, titratable), nitroprusside (rapid but cyanide toxicity risk), nitroglycerin (ACS/pulmonary oedema). SPECIAL CASES: aortic dissection = rapid reduction (SBP to 100-120), pre-eclampsia = magnesium sulphate + labetalol/hydralazine, phaeochromocytoma = ALPHA-blockade before beta-blockade.
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- Do NOT reduce BP too rapidly in chronic hypertension — cerebral autoregulation is shifted right. Rapid reduction → cerebral hypoperfusion → ischaemic stroke
- Aortic dissection = exception to slow reduction — rapid reduction to SBP 100-120 is required
- Phaeochromocytoma: ALPHA-blockade (phenoxybenzamine) BEFORE beta-blockade — beta-blocker first causes unopposed alpha stimulation → hypertensive crisis
- Eclampsia: give magnesium sulphate FIRST (seizure prevention/treatment), then BP control
Meet the patient
A 58-year-old man arrives in the resus bay with a thunderclap headache, blurred vision, and confusion. BP 230/140, HR 95. Fundoscopy shows papilloedema and flame haemorrhages. The ECG shows LVH with strain; the creatinine is 180. No chest pain. The CT brain shows no haemorrhage.[1]
The registrar asks for sublingual nifedipine. Stop. This is a hypertensive emergency with cerebral involvement, and three rules now govern the next hour: an arterial line, an IV titratable infusion, and a MAP reduced by no more than 25 per cent — never to "normal", never with sublingual nifedipine. The brain of a chronic hypertensive lives on a right-shifted autoregulation curve; dropping it to 120/80 causes the stroke you were trying to prevent.[1][2]
References28ShowHide
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