Hypertensive Emergency

Severe elevation in blood pressure (typically SBP ≥180mmHg and/or DBP ≥120mmHg) associated with acute, progressive target-organ damage, distinguishes this from hypertensive urgency, where BP is similarly elevated but without acute end-organ compromise. The absolute BP value is less important than the presence of acute organ injury in determining emergency status and treatment urgency.

Classified by affected organ system:

• Hypertensive encephalopathy
• Acute aortic dissection
• Acute coronary syndrome/unstable angina with severe hypertension
• Acute pulmonary edema/decompensated heart failure
• Acute kidney injury
• Eclampsia/severe pre-eclampsia (pregnancy-specific)
• Hemorrhagic or ischemic stroke with severe hypertension
• Retinal hemorrhage/papilledema (malignant hypertension)
• Microangiopathic hemolytic anemia (malignant hypertension)

• Severe headache, visual disturbance, confusion, nausea/vomiting (encephalopathy)
• Chest pain (ACS, aortic dissection: classically tearing, radiating to back, unequal limb BPs/pulses)
• Dyspnea, orthopnea, frothy sputum (pulmonary edema)
• Focal neurological deficit, reduced consciousness (stroke: but note ischemic stroke often warrants permissive hypertension)
• Oliguria, hematuria (renal involvement)
• Fundoscopy: papilledema, flame hemorrhages, cotton wool spots, exudates (grade III-IV hypertensive retinopathy), hallmark of malignant hypertension
• Seizures (encephalopathy or eclampsia if pregnant/postpartum)
• Examination for underlying/precipitating causes: radiofemoral delay, abdominal/renal bruit, signs of pheochromocytoma (episodic headache/sweating/palpitations), medication/substance history (cocaine, sympathomimetics, abrupt antihypertensive withdrawal, especially clonidine/beta-blockers)

• Confirm BP on repeated measurement, both arms (discrepancy suggests dissection)
• Fundoscopy: mandatory in all suspected hypertensive emergencies
• ECG: ischemia, LVH strain pattern, arrhythmia
• Bloods: FBC and blood film (schistocytes, microangiopathic hemolysis in malignant hypertension), U&E/creatinine (AKI), troponin if ACS suspected, LFTs, coagulation
• Urinalysis: proteinuria, hematuria
• CXR: pulmonary edema, widened mediastinum (dissection, proceed to CT angiography if suspected)
• CT head: if encephalopathy/stroke suspected, distinguishes hemorrhagic from ischemic
• CT angiography chest/abdomen: if aortic dissection suspected, do not delay for other workup if clinical suspicion high
• Pregnancy test in women of reproductive age (exclude eclampsia/pre-eclampsia as cause)
• Toxicology screen if substance-induced hypertensive crisis suspected

Differentials: hypertensive urgency (no end-organ damage, manage with gradual oral BP reduction, no need for IV therapy or ICU), pain/anxiety-related BP elevation (reassess after analgesia/reassurance), white-coat effect.

General principle: reduce MAP by no more than 25% in the FIRST HOUR (except specific exceptions below), overly rapid correction risks cerebral, coronary, or renal hypoperfusion given impaired autoregulation in chronically hypertensive vasculature.

• ICU/HDU admission, continuous BP monitoring (arterial line preferred), IV antihypertensive titration

Agent selection by scenario:

• General/encephalopathy: labetalol IV bolus 20mg over 2 min then infusion 1-2mg/min (titrate), or nicardipine infusion 5mg/hr titrated by 2.5mg/hr every 5-15 min (max 15mg/hr)
• Aortic dissection: target SBP <120mmHg AND HR <60 within 20 minutes, labetalol IV first-line (combined alpha/beta blockade controls both BP and shear stress), or esmolol infusion + nitroprusside if additional BP control needed; avoid pure vasodilators alone (reflex tachycardia increases aortic wall stress), urgent cardiothoracic/vascular surgery referral
• Acute pulmonary edema: IV GTN infusion, titrate rapidly, ± IV furosemide, non-invasive ventilation (CPAP)
• ACS with severe hypertension: IV GTN, beta-blocker if not contraindicated, avoid nifedipine/other agents causing reflex tachycardia
• Hypertensive encephalopathy: labetalol or nicardipine, target 25% MAP reduction in first hour then more gradual over following 23 hours
• Acute kidney injury: labetalol or nicardipine, avoid ACE inhibitors/ARBs acutely
• Ischemic stroke: generally permissive hypertension UNLESS thrombolysis/thrombectomy planned (then target <185/110 pre-treatment, <180/105 post-treatment) or BP extremely high (>220/120)
• Catecholamine excess (cocaine, pheochromocytoma, MAOI interaction, sympathomimetic overdose): AVOID beta-blockers as sole/first agent (unopposed alpha stimulation risk), use phentolamine, or benzodiazepines first-line for cocaine-associated hypertension/chest pain

Oral transition: once IV control achieved and stable (typically 6-24 hours), transition to oral antihypertensive regimen, continue gradual reduction toward target over following days, identify and address underlying/secondary cause and precipitant.

Referral: cardiothoracic/vascular surgery for aortic dissection (emergency), nephrology for renal involvement/malignant hypertension workup, obstetrics immediately if pregnant/postpartum.