Hypertensive emergency
Formal Definition
Severely elevated blood pressure (>180/120 mmHg) with evidence of acute ongoing end-organ damage; requires immediate but controlled blood pressure reduction with IV antihypertensives in an ICU or critical care setting; target reduction is typically MAP reduction of 20-25% in the first hour, then gradual reduction to 160/100-110 over 2-6 hours.
How It's Used on the Ward
Hypertensive emergency — the BP is so high it is actively damaging organs right now; ICU, IV drips, arterial line.
Example
"BP 240/140, new-onset global aphasia and right hemiparesis, CT negative for hemorrhage. Diagnosis: hypertensive emergency with acute hypertensive encephalopathy/stroke. Arterial line placed. Started nicardipine infusion 5 mg/h, titrating to MAP goal 110-130. Neurology consulted. Blood pressure will be lowered carefully — too fast risks worsening cerebral perfusion in stroke."
Clinical Context
Key principle: speed of BP reduction must be tailored to the specific end-organ injury. Aortic dissection → reduce SBP to <120 in minutes (labetalol + nitroprusside). Stroke → debate: AHA guidelines vary by stroke type, generally allow permissive hypertension >220/120 for ischemic stroke unless planning for thrombolysis. Hypertensive encephalopathy → reduce MAP 20-25% in first hour. Agents: nicardipine (calcium channel blocker, easy titration), labetalol (alpha + beta blocker, ideal for dissection), nitroprusside (potent, short-acting, cyanide toxicity risk with prolonged use), clevidipine (ultra-short acting IV CCB). Avoid: sublingual nifedipine, IMO beta-blockers in aortic dissection.