When do you treat hypertension in the emergency department (ED)?

When to Treat Blood Pressure in the Emergency Department

Treat blood pressure in the ED immediately only when there is evidence of acute target organ damage (hypertensive emergency), defined as BP >180/120 mmHg WITH acute organ injury—not based on the BP number alone. 1

Critical Distinction: Emergency vs. Urgency

The presence of acute target organ damage—not the absolute BP value—determines whether immediate treatment is required 1:

Hypertensive Emergency (Requires Immediate IV Treatment)

• BP >180/120 mmHg PLUS evidence of acute organ damage 1, 2
• Requires ICU admission with continuous arterial monitoring 3, 1
• Demands immediate parenteral (IV) antihypertensive therapy 1
• Without treatment, carries 79% mortality at 1 year 1

Hypertensive Urgency (Does NOT Require Immediate Treatment)

• BP >180/120 mmHg WITHOUT acute organ damage 1, 2
• Can be managed with oral medications and outpatient follow-up 1
• Does NOT require hospital admission or IV medications 1
• Rapid BP lowering may actually be harmful 1

Identifying Target Organ Damage

You must actively assess for these specific manifestations 1, 2:

Neurologic Damage

• Hypertensive encephalopathy: altered mental status, headache with vomiting, visual disturbances, seizures 3, 1
• Acute ischemic stroke 3, 1
• Intracranial hemorrhage 3, 1

Cardiac Damage

• Acute coronary syndrome/myocardial infarction 3, 1
• Acute left ventricular failure with pulmonary edema 3, 1
• Cardiogenic pulmonary edema 3

Vascular Damage

• Acute aortic dissection 3, 1

Renal Damage

• Acute kidney injury 3, 1
• Malignant hypertension with thrombotic microangiopathy 3, 1

Ophthalmologic Damage

• Retinal hemorrhages, cotton wool spots, papilledema on fundoscopy 1

Essential Diagnostic Workup

When hypertensive emergency is suspected, obtain immediately 1:

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

Treatment Approach for Hypertensive Emergency

Standard BP Reduction Target 3, 1

• First hour: Reduce mean arterial pressure by 20-25% 3, 1
• Next 2-6 hours: If stable, reduce to 160/100 mmHg 1
• Next 24-48 hours: Cautiously normalize BP 1

Critical caveat: Avoid excessive acute drops >70 mmHg systolic, which can precipitate cerebral, renal, or coronary ischemia 1

First-Line IV Medications 3, 1

Labetalol or nicardipine are preferred for most hypertensive emergencies 3, 1:

• Labetalol: 0.25-0.5 mg/kg IV bolus or 2-4 mg/min continuous infusion 1
• Nicardipine: 5 mg/hr IV infusion, titrate by 2.5 mg/hr every 15 minutes (max 15 mg/hr) 1

Condition-Specific Modifications 3, 1

Acute aortic dissection (most aggressive target):

• Target SBP <120 mmHg and heart rate <60 bpm within 20 minutes 3, 1
• Use esmolol plus nitroprusside/nitroglycerin 3, 1

Acute pulmonary edema:

• Target SBP <140 mmHg immediately 3, 1
• Use nitroglycerin or nitroprusside with loop diuretic 3, 1

Acute ischemic stroke:

• Generally withhold BP lowering unless BP >220/120 mmHg 3
• If thrombolysis planned: lower to <185/110 mmHg 3
• Reduce MAP by only 15% over 1 hour 3

Acute hemorrhagic stroke:

• If SBP >180 mmHg: lower to 130-180 mmHg 3
• Use labetalol as first-line 3

Critical Medications to AVOID

Never use these agents in hypertensive emergencies 1, 4:

• Short-acting nifedipine: causes unpredictable precipitous drops and reflex tachycardia 3, 1
• Hydralazine as first-line: unpredictable response and prolonged duration 1
• Sodium nitroprusside except as last resort: risk of cyanide toxicity 1, 4

Management of Hypertensive Urgency

For asymptomatic severe hypertension WITHOUT organ damage 1:

• Initiate or adjust oral antihypertensive medications 1
• Arrange outpatient follow-up within 2-4 weeks 1
• Target BP <130/80 mmHg to be achieved over weeks to months 1
• Do NOT admit to hospital 1
• Do NOT use IV medications 1

Important consideration: Up to one-third of patients with diastolic BP >95 mmHg normalize before follow-up, and rapid BP lowering may be harmful 1

Common Clinical Pitfalls

The rate of BP rise is often more important than the absolute value 1, 2—patients with chronic hypertension tolerate higher pressures due to altered autoregulation 1

Many patients with acute pain or distress have transiently elevated BP that normalizes when the underlying condition is treated—avoid treating the BP number alone 1

Asymptomatic severe hypertension does NOT automatically require treatment in the ED—absence of symptoms does not rule out organ damage, but presence of organ damage is what mandates immediate treatment 2

Screen for secondary causes after stabilization—20-40% of patients with malignant hypertension have secondary causes including renal artery stenosis, pheochromocytoma, or primary aldosteronism 1, 2