Hypertensive Emergency: Criteria and Treatment
A hypertensive emergency is defined as severe blood pressure elevation (>180/120 mmHg) with evidence of new or worsening target organ damage, requiring immediate blood pressure reduction to prevent progressive organ failure. 1
Definition and Clinical Presentation
- Hypertensive emergency involves substantially elevated blood pressure with acute hypertensive-mediated organ damage (HMOD) affecting the retina, brain, heart, large arteries, or kidneys 2
- The 1-year mortality rate for untreated hypertensive emergencies exceeds 79%, with median survival of only 10.4 months, emphasizing the need for prompt recognition and treatment 1
- Hypertensive emergency must be distinguished from hypertensive urgency, which involves severe blood pressure elevation without progressive target organ dysfunction 1
Specific presentations of hypertensive emergencies include:
- Malignant hypertension: Severe BP elevation (commonly >200/120 mm Hg) with advanced bilateral retinopathy (hemorrhages, cotton wool spots, papilledema) 2
- Hypertensive encephalopathy: Severe BP elevation with lethargy, seizures, cortical blindness, and coma 2
- Hypertensive thrombotic microangiopathy: Severe BP elevation with hemolysis and thrombocytopenia 2
- Other presentations: Severe BP elevation with cerebral hemorrhage, acute stroke, acute coronary syndrome, cardiogenic pulmonary edema, aortic aneurysm/dissection, or severe preeclampsia/eclampsia 2
Diagnostic Workup
- Medical history: Assess for preexisting hypertension, onset and duration of symptoms, potential causes (medication nonadherence, lifestyle changes, use of BP-elevating drugs) 2
- Physical examination: Thorough cardiovascular and neurologic assessment 2
- Laboratory analysis: Hemoglobin, platelets, creatinine, sodium, potassium, LDH, haptoglobin, urinalysis for protein, urine sediment 2
- Essential examinations: Fundoscopy, ECG 2
- Additional investigations based on presentation: Troponins (chest pain), chest x-ray (congestion/fluid overload) 2
Treatment Approach
Patients with hypertensive emergencies should be admitted to an intensive care unit for continuous blood pressure monitoring and parenteral administration of appropriate antihypertensive agents to prevent further target organ damage. 1
Blood Pressure Reduction Targets
- For most hypertensive emergencies: Reduce mean arterial pressure by no more than 25% within the first hour, then further reduce to 160/100-110 mmHg within the next 2-6 hours 1
- After stability is confirmed, gradually reduce blood pressure toward normal over the next 24-48 hours 1
- Special situations require different targets (see table below) 2
| Clinical Presentation | Timeline and Target BP |
|---|---|
| Malignant hypertension with/without TMA or acute renal failure | Several hours, MAP −20% to −25% |
| Hypertensive encephalopathy | Immediate, MAP −20% to −25% |
| Acute ischemic stroke and SBP >220 mm Hg or DBP >120 mm Hg | 1 h, MAP −15% |
| Acute ischemic stroke with indication for thrombolytic therapy and SBP >185 mm Hg or DBP >110 mm Hg | 1 h, MAP −15% |
| Acute hemorrhagic stroke and SBP >180 mm Hg | Immediate, 130<SBP<180 mm Hg |
| Acute coronary event | Immediate, SBP <140 mm Hg |
| Acute cardiogenic pulmonary edema | Immediate, SBP <140 mm Hg |
| Acute aortic disease | Immediate, SBP <120 mm Hg and heart rate <60 bpm |
| Eclampsia and severe preeclampsia/HELLP | Immediate, SBP <160 mm Hg and DBP <105 mm Hg |
First-Line Parenteral Medications
- Nicardipine: Initial dose 5 mg/h IV, increasing every 5 min by 2.5 mg/h to maximum 15 mg/h; suitable for most hypertensive emergencies except acute heart failure 1, 3
- Labetalol: 20-80 mg IV bolus every 10 min or 0.4-1.0 mg/kg/h IV infusion; suitable for most hypertensive emergencies except acute heart failure 1, 4
- Clevidipine: Initial dose 1-2 mg/h IV, doubling every 90 seconds until blood pressure approaches target, maximum 32 mg/h; contraindicated in patients with soy/egg allergies or lipid metabolism disorders 1
- Enalaprilat: Useful for hypertensive emergencies, particularly beneficial for patients at high risk of cerebral hypotensive episodes due to impaired cerebral circulation 5
Common Pitfalls to Avoid
- Avoid excessive blood pressure reduction, as too rapid or excessive lowering can cause cerebral, coronary, or renal hypoperfusion 1
- Avoid short-acting nifedipine due to the risk of uncontrolled blood pressure reduction 1, 6
- Avoid oral agents for initial management of hypertensive emergencies, as parenteral therapy provides more reliable and titratable control 1
- Sodium nitroprusside should be used with caution because of its toxicity (metabolized to thiocyanate and cyanide) 6, 7
- Avoid hydralazine, immediate release nifedipine, and nitroglycerin as first-line therapies due to significant toxicities and/or adverse effects 6
- If hypotension occurs, place the patient in the supine position and administer intravenous normal saline 5
Transition to Oral Therapy
- Oral antihypertensive therapy can usually be instituted after 6-12 hours of parenteral therapy 7
- After stability is confirmed, the patient can be moved out of the intensive care unit 7
- Consider screening for secondary causes of hypertension 7
- Long-term follow-up to ensure adequate control of hypertension is necessary to prevent further target-organ damage and recurrence of hypertensive emergency 7