What is the initial management of a hypertension emergency?

Initial Management of Hypertensive Emergency

Immediate Triage and Assessment

Admit the patient immediately to the ICU for continuous blood pressure monitoring and parenteral antihypertensive therapy. 1, 2

The critical first step is distinguishing a hypertensive emergency from urgency:

• Hypertensive emergency: BP >180/120 mmHg WITH acute target organ damage requiring immediate intervention 1, 2
• Hypertensive urgency: Severe BP elevation WITHOUT acute organ damage, manageable with oral agents outpatient 2

The presence of target organ damage—not the absolute BP number—defines the emergency. 2 The rate of BP rise may be more important than the absolute value, as patients with chronic hypertension often tolerate higher pressures. 2

Rapidly Assess for Target Organ Damage

Perform focused evaluation for: 1, 2

• Neurologic: Altered mental status, headache, visual disturbances, seizures (hypertensive encephalopathy), stroke symptoms
• Cardiac: Chest pain, dyspnea (acute coronary syndrome, pulmonary edema)
• Renal: Acute kidney injury, hematuria
• Vascular: Aortic dissection symptoms
• Ophthalmologic: Fundoscopy for hemorrhages, exudates, papilledema (malignant hypertension)

Essential Laboratory Evaluation

Obtain immediately: 2

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

Blood Pressure Reduction Goals

For most hypertensive emergencies, reduce systolic BP by no more than 25% within the first hour, then if stable to 160/100 mmHg over the next 2-6 hours, then cautiously to normal over 24-48 hours. 1, 2

Exception: More Aggressive Targets for Specific Conditions

• Aortic dissection: Target SBP <120 mmHg and heart rate <60 bpm immediately 2
• Acute coronary syndrome: Target SBP <140 mmHg immediately 2
• Acute pulmonary edema: Target SBP <140 mmHg immediately 2
• Acute ischemic stroke: Avoid BP reduction unless >220/120 mmHg; if treating, reduce MAP by 15% within first hour 2
• Acute hemorrhagic stroke: If SBP ≥220 mmHg, carefully lower to 140-160 mmHg within 6 hours 2

Critical pitfall: Avoid excessive acute drops in systolic BP (>70 mmHg), which can precipitate cerebral, renal, or coronary ischemia. 2 Patients with chronic hypertension have altered autoregulation and cannot tolerate acute normalization. 2

First-Line Intravenous Medications

Nicardipine (Preferred Agent)

Nicardipine is the preferred first-line agent for most hypertensive emergencies due to its titratable nature, predictable effects, and preservation of cerebral blood flow. 1, 2

Dosing: 3

• Start at 5 mg/hr IV infusion
• For gradual reduction: Increase by 2.5 mg/hr every 15 minutes to maximum 15 mg/hr
• For more rapid reduction: Titrate every 5 minutes
• Dilute to 0.1 mg/mL concentration
• Change infusion site every 12 hours if using peripheral vein

Advantages: Rapid onset, easily titratable, does not increase intracranial pressure, maintains cerebral blood flow 2

Labetalol (Alternative Agent)

Labetalol is particularly effective for hypertensive emergencies with renal involvement or hypertensive encephalopathy. 1, 2

Dosing: 2

• 0.25-0.5 mg/kg IV bolus, OR
• 2-4 mg/min continuous infusion until goal BP reached, then 5-20 mg/hr maintenance

Condition-Specific First-Line Agents

• Hypertensive encephalopathy: Labetalol or nicardipine 2
• Acute coronary syndrome: Nitroglycerin 5-10 mcg/min IV, titrate by 5-10 mcg/min every 5-10 minutes 2
• Acute pulmonary edema: Nitroglycerin or nitroprusside 1, 2
• Aortic dissection: Esmolol plus nitroprusside or nitroglycerin 2
• Malignant hypertension with renal failure: Labetalol 2

Monitoring Requirements

Place arterial line for continuous BP monitoring in the ICU. 2

Monitor continuously: 1, 2

• Blood pressure (preferably via arterial line)
• Heart rate (watch for reflex tachycardia)
• Neurological status (mental status, visual changes, focal deficits)
• Cardiac function (ECG, symptoms)
• Renal function (urine output, creatinine)

Critical Medications to Avoid

Do not use the following agents: 2

• Immediate-release nifedipine: Unpredictable precipitous BP drops, reflex tachycardia
• Hydralazine: Unpredictable effects, difficult titration
• Sodium nitroprusside: Risk of thiocyanate toxicity (use only if other agents fail and limit to <48-72 hours) 2, 4

Transition to Oral Therapy

After stabilization (typically 6-12 hours of parenteral therapy): 5

• Initiate oral antihypertensive therapy with combination of RAS blockers, calcium channel blockers, and diuretics 2
• When switching to oral nicardipine: Give first dose 1 hour prior to discontinuing IV infusion 3
• Target long-term SBP 120-129 mmHg for most adults 2

Post-Stabilization Evaluation

Screen for secondary hypertension causes after stabilization, as 20-40% of malignant hypertension cases have secondary causes. 2 Evaluate for:

• Renal artery stenosis
• Pheochromocytoma
• Primary aldosteronism
• Medication non-compliance (most common trigger) 2