Hypertensive Crisis

Table of Contents

Introduction

Severe hypertension defined as:
- > 180/120 (sBP or dBP)
- Assess for evidence of end-organ damage (separates urgency from emergencies)
Hypertensive Urgency: Severe hypertension without evidence of end-organ damage
- Manage with oral medications to reduce BP to ≤ 160/100 (over several days)
- No URGENT IV therapy needed
Hypertensive Emergency
- End-organ damage found
- Use IV medication to lower blood pressure (i.e. by 15-25%)

Sufficient elevation of BP (undefined, usually >200/140) to cause:
- Papilledema
- Vascular Damage (retinal hemorrhages, bulging discs, mental status change, increasing creatinine)

Malignant HTN + papilledema
Cerebrovascular
- Hypertensive encepalopathy
- CVA with severe hypertension
- Intracerebral hemorrhage
- SAH
Cardiac
- Aortic dissection
- LV failure (new onset CHF)
- MI
Renal Failure

Goal is to assess for end-organ damage
Physical exam
- Neurologic exam (mental status, visual fields, acuity)
- Volume status (fluid overload?)
- Aortic dissection (symmetry of pulses, bilateral blood pressures)
Investigations:
- Electrolytes, BUN, creatinine, CBC, CK/troponin (ischemia signs?), urinalysis, renal injury, drug levels (cocaine, amphetamines)
- EKG, CXR
- Brain imaging if mental status decreased or neuro findings.
- CT Angio if concerned of aortic dissection.
Management:
- Hypertensive Urgency: ORAL MEDICATIONS (see other sections)
- Hypertensive Emergency: IV MEDICATIONS (keep reading)
  - Short-acting IV antihypertensive infusions to limit end-organ damage.
    - First line: Sodium nitroprusside (controlled BP reduction, continuous infusion, neec surveillance)
    - Second line: boluses of: labetalol, phentolamine, nitroglycerin, hydralazine.
- Should not be lowered to normal, or lowered any further than to stop acute end-organ damage.
  - Generally do not reduce MAP by >25% (sometimes diastolic of 100 (whichever is higher)) in 1 hour.
    - limit of cerebral BP autoregulation. if lower >50% then cerebral ischemia insues.
    - If new focal deficits, stop antihypertensives!
Table below shows options for hypertensive crisis

IV Antihypertensive Agents for Hypertensive Crises

Agent (Class)	Dose (Delivery)	Onset	Duration	Notes	Adverse Effects (All Cause Hypotension)
Nitroprusside (vasodilator)	0.25-10 µg/kg/min (IV)	Immediate	1-10 min	Easy to titrate; often first choice for acute situations	Risk of cyanide toxicity
Nitroglycerin (vasodilator)	0.25-5 µg/kg/min (IV)	Immediate	3-5 min	Used for myocardial ischemia; tolerance may develop	Headache, bradycardia
Hydralazine (vasodilator)	5-20 mg every 4-6 hours (IV)	1-5 min	1-4 hours	Safe in pregnancy	Nausea, headache, tachycardia
Labetalol (α- and β-blocker)	20 mg IV over 2min then infuse 1-2 mg/min (max dose = 300mg) or 20mg every 10 min	2-5 min	3-6 hours	Can be switched to oral	Bradycardia, heart block, nausea, bronchospasm
Enalaprilat (ACE inhibitor)	1.25 mg every 6 hours (IV)	15 min	6-12 hours	Can be switched to oral; good for left ventricular failure	Prolonged hypotension
Nicardipine (calcium channel blocker)	5 mg/hour titrated up to 15 mg/hour (IV)	1-5 min	3-6 hours	Often used for patients with stroke	Myocardial ischemia, tachycardia, headache
Fenoldopam (dopamine agonist)	0.03-0.1 µg/kg/min (IV)	10 min	1 hour	Can be titrated up slowly to 1.6 µg/kg/min; may be protective of kidneys	Flushing, headache, nausea, tachycardia, possibly increased myocardial ischemia
Phentolamine (α-blocker)	5-20 mg (IV)	15-20 min	30-45 min	Used for diagnosis of and surgery for pheochromocytoma	Nausea, arrhythmia
Esmolol	500 ug/kg bolus + 50 ug/kg/min incr. infusion by 25 q5m to target heart rate			- For heart rate control

Source: MKSAP16