Management of Hypertensive Emergency
In a hypertensive emergency, immediate hospitalization in an ICU with continuous BP monitoring and IV antihypertensive therapy using titratable short-acting agents is required, with labetalol or nicardipine as first-line treatments for most presentations. 1
Definition and Classification
Hypertensive crisis is defined as severe blood pressure elevation (>180/120 mmHg) requiring prompt clinical attention and is classified into two categories:
- Hypertensive Emergency: Severe hypertension WITH end-organ damage
- Hypertensive Urgency: Severe hypertension WITHOUT end-organ damage
Initial Assessment
Evaluation for end-organ damage should include:
- Physical examination
- Laboratory tests (renal panel)
- ECG
- Additional testing based on symptoms:
- Echocardiogram
- Neuroimaging
- Chest CT
Signs of end-organ damage include:
- Neurological: Hypertensive encephalopathy, stroke, intracranial hemorrhage
- Cardiovascular: Acute coronary syndrome, acute heart failure, pulmonary edema, aortic dissection
- Renal: Acute kidney injury, acute renal failure
- Other: Eclampsia, microangiopathic hemolytic anemia
Caution: Bradycardia with severe hypertension should raise immediate concern for increased intracranial pressure 1
Treatment Approach
Blood Pressure Reduction Targets
- Initial reduction: No more than 25% within the first hour
- Then reduce to 160/100 mmHg within 2-6 hours
- Cautiously reduce to normal over 24-48 hours 1
Warning: Overly aggressive BP reduction can lead to cerebral, cardiac, or renal hypoperfusion 1
Special Conditions with Different Targets
- Aortic dissection: Reduce SBP to <140 mmHg during first hour, then to <120 mmHg
- Severe preeclampsia/eclampsia: Reduce SBP to <140 mmHg during first hour
- Pheochromocytoma crisis: Reduce SBP to <140 mmHg during first hour 1
First-Line Medications by Clinical Presentation
| Clinical Presentation | First-Line Treatment | Alternative |
|---|---|---|
| Most hypertensive emergencies | Labetalol | Nicardipine |
| Acute coronary event | Nitroglycerin | Labetalol |
| Acute pulmonary edema | Nitroglycerin + loop diuretic | Labetalol + loop diuretic |
| Aortic dissection | Esmolol + Nitroprusside | Labetalol, Nicardipine |
| Malignant hypertension with/without acute renal failure | Labetalol | Nicardipine, Nitroprusside |
| Hypertensive encephalopathy | Labetalol | Nicardipine, Nitroprusside |
| Acute ischemic stroke (BP >220/120 mmHg) | Labetalol | Nicardipine |
| Acute hemorrhagic stroke (SBP >180 mmHg) | Labetalol | Nicardipine |
Medication Administration
Labetalol (First-line for most presentations)
- Dose: 10 mg IV over 1-2 min
- May be repeated or doubled every 10-20 min
- Maximum dose: 300 mg 1
Nicardipine (First-line alternative)
- Initial: 5 mg/h
- Increase every 5 min by 2.5 mg/h
- Maximum: 15 mg/h
- Administration: Slow continuous infusion via central line or large peripheral vein
- Change infusion site every 12 hours if administered via peripheral vein 1, 2
- Preparation: Dilute each 25 mg vial with 240 mL of compatible IV fluid to yield 0.1 mg/mL 2
Other Medications
- Clevidipine: Initial 1-2 mg/h, doubling every 90 sec until BP approaches target
- Sodium nitroprusside: Initial 0.3-0.5 mcg/kg/min; increase in increments of 0.5 mcg/kg/min; max 10 mcg/kg/min
- Nitroglycerin: Initial 5 mcg/min; increase in increments of 5 mcg/min every 3-5 min to max 20 mcg/min 1
Important: Avoid hydralazine as first-line treatment due to unpredictable response and prolonged duration. Use sodium nitroprusside cautiously due to risk of cyanide toxicity with prolonged use 1
Monitoring and Follow-up
- Monitor vital signs, especially BP, every 30 minutes during first 2 hours
- Continue monitoring for at least several hours to ensure stability before discharge
- Schedule follow-up within 24 hours after discharge
- Continue with monthly follow-up visits until target BP is reached
- Monitor specifically for renal function improvement, reduction in proteinuria, and regression of left ventricular mass 1
Prognosis
The untreated 1-year mortality rate for hypertensive emergencies exceeds 79%, with median survival of only 10.4 months, highlighting the critical importance of prompt and appropriate management 1. Patients with hypertensive emergency are at increased risk of cardiovascular and renal disease compared to hypertensive patients without emergency.
Special Populations
- Pregnancy-related hypertensive crisis: Use IV labetalol or nicardipine with magnesium
- Autonomic hyperreactivity due to stimulant intoxication: Start with benzodiazepines before antihypertensive therapy 1