What is the difference between a hypertensive (HTN) emergency and a hypertensive urgency?

Hypertensive Emergency vs. Hypertensive Urgency

A hypertensive emergency is defined as blood pressure exceeding 180/120 mmHg WITH acute target organ damage requiring immediate ICU admission and IV therapy, while hypertensive urgency is the same BP elevation WITHOUT organ damage and can be managed with oral medications as an outpatient. 1

Key Distinguishing Factor

The presence or absence of acute target organ damage—not the absolute blood pressure number—is the critical differentiating feature between these two conditions. 1 The rate of BP rise may actually be more important than the absolute BP level, as patients with chronic hypertension often tolerate higher pressures than previously normotensive individuals. 1

Hypertensive Emergency Criteria

Blood Pressure Threshold

• BP >180/120 mmHg 1, 2
• However, the specific BP threshold is less important than the presence of organ damage 1

Required Evidence of Target Organ Damage

Target organ damage must include one or more of the following: 1

Neurologic:

• Hypertensive encephalopathy (altered mental status, headache, visual disturbances, seizures)
• Intracranial hemorrhage
• Acute ischemic stroke
• Posterior reversible encephalopathy syndrome (PRES)

Cardiac:

• Acute myocardial infarction
• Acute left ventricular failure with pulmonary edema
• Unstable angina

Vascular:

• Aortic dissection or aneurysm

Renal:

• Acute kidney injury
• Hypertensive thrombotic microangiopathy

Ophthalmologic:

• Malignant hypertension with bilateral retinal hemorrhages, cotton wool spots, and papilledema 1

Obstetric:

• Severe preeclampsia or eclampsia 1

Clinical Significance

Without treatment, hypertensive emergencies carry a 1-year mortality rate >79% and median survival of only 10.4 months. 1

Hypertensive Urgency Criteria

Blood Pressure Threshold

• BP >180/120 mmHg 1, 3

Absence of Target Organ Damage

• No evidence of new or worsening end-organ injury 4, 5
• No acute neurologic, cardiac, vascular, renal, or ophthalmologic damage 1

Clinical Context

Up to one-third of patients with diastolic BP >95 mmHg normalize before follow-up, and rapid BP lowering may be harmful in these asymptomatic patients. 1

Management Implications

Hypertensive Emergency Management

• Immediate ICU admission (Class I recommendation, Level B-NR) 1
• Continuous arterial line BP monitoring 1
• Parenteral (IV) antihypertensive therapy with titratable short-acting agents 1, 4
• First-line IV medications: nicardipine, clevidipine, labetalol, or sodium nitroprusside 1
• BP reduction target: Reduce mean arterial pressure by 20-25% within the first hour, then if stable to 160/100 mmHg over 2-6 hours, then cautiously normalize over 24-48 hours 1
• Exception for aortic dissection: Target SBP <120 mmHg within 20 minutes 1

Hypertensive Urgency Management

• No hospital admission required 1
• Oral antihypertensive therapy 1, 4
• Outpatient follow-up within 2-4 weeks 1
• Gradual BP reduction over 24-48 hours 3
• Initiating or restarting long-acting antihypertensives (typically combination of ACE inhibitor/ARB, thiazide diuretic, and/or calcium channel blocker) 2

Critical Assessment Algorithm

When evaluating a patient with BP >180/120 mmHg: 1

1. Confirm BP elevation with repeat measurement using proper technique
2. Assess for symptoms suggesting organ damage (headache, visual changes, chest pain, dyspnea, neurologic symptoms)
3. Perform focused examination:
   • Brief neurologic exam (mental status, visual changes, focal deficits)
   • Cardiac assessment (signs of heart failure, acute coronary syndrome)
   • Fundoscopic exam (looking for bilateral retinal hemorrhages, cotton wool spots, papilledema)
4. Obtain essential labs: hemoglobin, platelets, creatinine, sodium, potassium, LDH, haptoglobin, urinalysis, troponins if chest pain 1
5. ECG to assess for cardiac involvement 1

Common Pitfalls to Avoid

• Do not admit patients with asymptomatic hypertension without evidence of acute target organ damage 1
• Do not confuse subconjunctival hemorrhage with malignant hypertensive retinopathy—true malignant hypertension requires bilateral retinal hemorrhages, cotton wool spots, or papilledema 1
• Do not rapidly lower BP in hypertensive urgency—this may cause harm through hypotension-related complications 1
• Avoid excessive acute drops >70 mmHg systolic—this can precipitate cerebral, renal, or coronary ischemia, particularly in patients with chronic hypertension who have altered autoregulation 1
• Do not use IV medications for hypertensive urgency—oral therapy is appropriate 1
• Do not dismiss "normal" BP readings in patients with concerning symptoms—BP may fluctuate in hypertensive emergencies 1