What is the recommended management for a hypertensive crisis, including how to distinguish a hypertensive emergency from a hypertensive urgency and the appropriate intravenous and oral antihypertensive regimens?

Hypertensive Crisis Management

Distinguishing Emergency from Urgency

The critical distinction between hypertensive emergency and urgency is the presence or absence of acute target-organ damage, not the absolute blood pressure value. 1

Hypertensive Emergency

• Defined as BP >180/120 mmHg WITH acute target-organ damage requiring immediate ICU admission and IV therapy 1, 2
• Target-organ damage includes:
  • Neurologic: altered mental status, seizures, hypertensive encephalopathy, acute stroke, intracranial hemorrhage 1
  • Cardiac: acute MI, unstable angina, acute left ventricular failure with pulmonary edema 1
  • Vascular: aortic dissection or aneurysm 1
  • Renal: acute kidney injury, thrombotic microangiopathy 1
  • Ophthalmologic: bilateral retinal hemorrhages, cotton-wool spots, or papilledema (grade III-IV retinopathy) on fundoscopy 1
  • Obstetric: severe preeclampsia or eclampsia 1
• Untreated, carries >79% one-year mortality and median survival of only 10.4 months 1

Hypertensive Urgency

• Defined as BP >180/120 mmHg WITHOUT acute target-organ damage 1
• Managed with oral antihypertensives and outpatient follow-up within 2-4 weeks 1
• Hospital admission and IV medications are not indicated 1, 2

Blood Pressure Reduction Targets

For Hypertensive Emergency (Without Compelling Conditions)

• First hour: Reduce SBP by no more than 25% (or MAP by 20-25%) 1, 2
• Hours 2-6: Lower to ≤160/100 mmHg if stable 1, 2
• Hours 24-48: Gradually normalize blood pressure 1, 2
• Critical: Avoid systolic drops >70 mmHg to prevent cerebral, renal, or coronary ischemia 1

For Compelling Conditions (More Aggressive Targets)

Condition	Target SBP	Timeframe
Aortic dissection	<120 mmHg	Within 20 minutes [1,2]
Severe preeclampsia/eclampsia or pheochromocytoma	<140 mmHg	Within first hour [1,2]
Acute coronary syndrome or pulmonary edema	<140 mmHg	Immediately [1,2]
Acute intracerebral hemorrhage (SBP ≥220 mmHg)	140-180 mmHg	Within 6 hours [1]

For Hypertensive Urgency

• First 24-48 hours: Gradually reduce to <160/100 mmHg 1
• Subsequent weeks: Aim for <130/80 mmHg 1
• Rapid lowering should be avoided to prevent hypoperfusion-related injury 1

Intravenous Antihypertensive Regimens (Emergency)

First-Line IV Agents

Nicardipine (preferred for most emergencies except acute heart failure):

• Start 5 mg/h IV infusion, titrate by 2.5 mg/h every 15 minutes to maximum 15 mg/h 1, 2
• Onset 5-15 minutes, duration 30-40 minutes 1
• Preserves cerebral blood flow and does not raise intracranial pressure 1
• Preferred for hypertensive encephalopathy, malignant hypertension, and most general emergencies 1

Labetalol (preferred for aortic dissection, eclampsia, renal involvement):

• 10-20 mg IV bolus over 1-2 minutes, repeat or double every 10 minutes (max cumulative 300 mg) 1, 2
• Alternative: continuous infusion 2-8 mg/min 1
• Contraindications: reactive airway disease, COPD, heart block, bradycardia, decompensated heart failure 1

Clevidipine (alternative rapid-acting CCB):

• Start 1-2 mg/h IV infusion, double every 90 seconds until near target, then increase <2-fold every 5-10 minutes 1
• Maximum 32 mg/h 1
• Contraindication: soy/egg allergy 1

Condition-Specific IV Regimens

Acute Coronary Syndrome / Pulmonary Edema:

• Nitroglycerin IV 5-100 mcg/min ± labetalol 1, 2
• Avoid nicardipine monotherapy (reflex tachycardia worsens ischemia) 1

Aortic Dissection:

• Esmolol loading 500-1000 mcg/kg, then infusion 50-200 mcg/kg/min BEFORE any vasodilator 1, 2
• Add nitroprusside or nitroglycerin to achieve SBP ≤120 mmHg and HR <60 bpm 1
• Beta-blockade must precede vasodilator to prevent reflex tachycardia 1

Eclampsia / Severe Preeclampsia:

• Labetalol, hydralazine, or nicardipine 1
• Absolutely contraindicated: ACE inhibitors, ARBs, sodium nitroprusside 1

Agents to Avoid

Sodium Nitroprusside (last-resort only):

• Risk of cyanide toxicity with prolonged use (>30 minutes at ≥4 mcg/kg/min) or renal insufficiency 1, 3, 4, 5
• Requires thiosulfate co-administration when infusion ≥4 mcg/kg/min or >30 minutes 1

Immediate-Release Nifedipine:

• Absolutely contraindicated - causes unpredictable precipitous drops, stroke, and death 1, 3, 4, 5

Hydralazine:

• Not first-line due to unpredictable response and prolonged duration 1

Oral Antihypertensive Regimens (Urgency)

Preferred Oral Agents

• Extended-release nifedipine 30-60 mg PO (never immediate-release) 1
• Captopril 12.5-25 mg PO (caution in volume-depleted patients) 1
• Labetalol 200-400 mg PO (avoid in reactive airway disease, heart block, bradycardia) 1

Follow-Up

• Outpatient visit within 2-4 weeks 1
• Monthly follow-up until target BP <130/80 mmHg achieved 1

Critical Monitoring Requirements

• All hypertensive emergencies: ICU admission with continuous arterial-line BP monitoring (Class I recommendation) 1, 2
• Continuous cardiac monitoring and frequent assessment of target-organ function 2
• Serial neurologic, cardiac, and renal assessments 1

Essential Laboratory Evaluation

• Complete blood count (hemoglobin, platelets) to assess for microangiopathic hemolytic anemia 1
• Basic metabolic panel (creatinine, sodium, potassium) 1
• Lactate dehydrogenase and haptoglobin to detect hemolysis 1
• Urinalysis for protein and urine sediment 1
• Troponins if chest pain present 1
• ECG to assess for cardiac involvement 1

Post-Stabilization Management

• Screen for secondary causes (present in 20-40% of malignant hypertension): renal artery stenosis, pheochromocytoma, primary aldosteronism, renal parenchymal disease 1
• Address medication non-adherence (most common trigger for hypertensive emergencies) 1
• Transition to oral regimen combining RAS blocker, calcium-channel blocker, and diuretic after 24-48 hours 1
• Monthly follow-up until target BP achieved and organ damage regressed 1

Common Pitfalls to Avoid

• Do not admit patients with severe hypertension without evidence of acute target-organ damage 1
• Do not use IV agents for hypertensive urgency; oral therapy is appropriate 1
• Do not rapidly lower BP in urgency - can cause cerebral, renal, or coronary ischemia 1
• Do not normalize BP acutely in chronic hypertensives - altered autoregulation predisposes to ischemic injury 1
• Do not treat the BP number alone - up to one-third of patients with elevated BP normalize before follow-up 1
• Do not assume absence of symptoms equals absence of organ damage - focused exam including fundoscopy is essential 1