What is the indication for and treatment of a hypertensive emergency?

Hypertensive Emergency: Indications and Treatment

A hypertensive emergency is defined as severely elevated blood pressure (typically >180/120 mmHg) associated with acute hypertension-mediated end-organ damage requiring immediate BP reduction to prevent progressive organ failure. 1

Indications for Hypertensive Emergency

Hypertensive emergency is characterized by:

• Severely elevated BP with evidence of acute target organ damage to:
  • Heart
  • Brain
  • Kidneys
  • Retina
  • Large arteries 1

Specific Clinical Presentations Include:

1. Malignant hypertension: Severe BP elevation (commonly >200/120 mmHg) with advanced bilateral retinopathy (hemorrhages, cotton wool spots, papilledema) 1

2. Hypertensive encephalopathy: Severe BP elevation with lethargy, seizures, cortical blindness, or coma 1

3. Hypertensive thrombotic microangiopathy: Severe BP with hemolysis and thrombocytopenia 1

4. Other presentations:

   • Cerebral hemorrhage
   • Acute stroke with specific BP thresholds
   • Acute coronary syndrome
   • Cardiogenic pulmonary edema
   • Aortic dissection
   • Severe preeclampsia/eclampsia 1

Important: Patients with severely elevated BP without acute end-organ damage do NOT have a hypertensive emergency and can typically be treated with oral medications 1

Diagnostic Workup

• Medical history: Preexisting hypertension, symptom onset/duration, medication adherence, use of BP-elevating drugs
• Physical examination: Cardiovascular and neurologic assessment
• Laboratory tests: Hemoglobin, platelets, creatinine, electrolytes, LDH, haptoglobin, urinalysis
• Fundoscopy and ECG 1

Treatment Approach

General Principles:

• Patients with hypertensive emergency require admission for close monitoring 1
• Most cases require intravenous BP-lowering agents 1
• The type of target organ damage determines:
  • Drug of choice
  • Target BP
  • Timeframe for BP reduction 1

Medication Selection:

First-line IV agents based on clinical presentation:

Clinical Presentation	First Choice Medication(s)	Timeline and Target BP
Malignant hypertension	Labetalol, Nicardipine	Several hours, MAP −20% to −25%
Hypertensive encephalopathy	Labetalol, Nicardipine	Immediate, MAP −20% to −25%
Acute ischemic stroke (SBP >220 or DBP >120)	Labetalol, Nicardipine	1 hour, MAP −15%
Acute hemorrhagic stroke	Nicardipine, Labetalol	Immediate, 130<SBP<180 mmHg
Acute coronary event	Nitroglycerin, Esmolol, Labetalol	Immediate, SBP <140 mmHg
Acute pulmonary edema	Clevidipine, Nicardipine	Immediate, SBP <140 mmHg
Aortic dissection	Esmolol, Labetalol	Immediate, SBP <120 mmHg and HR <60 bpm
Eclampsia/severe preeclampsia	Hydralazine, Labetalol	Immediate, SBP <160 mmHg and DBP <105 mmHg
[1,2]

Specific Medication Dosing:

• Labetalol: 20-80 mg IV bolus every 10 minutes or 0.5-2 mg/min infusion; onset 5-10 minutes, duration 3-6 hours 2
• Nicardipine: 5-15 mg/h IV infusion; onset 5-10 minutes, duration >4 hours 2
• Clevidipine: Start at 2 mg/h IV, increase by 2 mg/h every 2 minutes until goal BP 2
• Esmolol: 0.5-1 mg/kg IV bolus, then 50-300 μg/kg/min continuous infusion 2
• Nitroglycerin: 0.3-10 μg/kg/min, increase by 0.5 μg/kg/min every 5 minutes 2
• Fenoldopam: 0.1 μg/kg/min IV, increase by 0.05-0.1 μg/kg/min every 15 minutes 2

BP Reduction Guidelines:

• Initial reduction should be no more than 25% within the first hour 2
• Continuous infusion of short-acting titratable agents is preferred over intermittent bolus dosing 2
• Monitor BP response every 5-15 minutes during initial treatment 2

Important Considerations and Contraindications

• Sodium nitroprusside should be avoided due to significant toxicity 3
• Nifedipine, nitroglycerin, and hydralazine should not be considered first-line therapies due to toxicities and adverse effects 3
• Contraindications:
  • Labetalol: Heart block, heart failure, asthma, bradycardia
  • Nitroprusside: Liver/kidney failure, use with PDE-5 inhibitors
  • Nicardipine: Use with caution in coronary ischemia
  • Enalaprilat: Avoid in acute myocardial infarction 2

Long-term Management

• Initiate or adjust long-term antihypertensive therapy once BP is stabilized 2
• Consider combination therapy for long-term control 2
• Single-pill combinations improve adherence 2
• Close follow-up is essential to adjust treatment and prevent complications 2

Pitfall to avoid: Do not rapidly lower BP in patients with chronic hypertension or ischemic stroke (unless thrombolysis is planned) as this can lead to cerebral hypoperfusion and worsen outcomes.