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Hypertensive Emergencies

By

George L. Bakris

, MD, University of Chicago School of Medicine

Reviewed/Revised Sep 2023
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Topic Resources

A hypertensive emergency is severe hypertension (often defined as systolic blood pressure (BP) ≥ 180 mm Hg and/or diastolic blood pressure ≥ 120 mm Hg) with signs of damage to target organs (primarily the brain, cardiovascular system, and kidneys). Diagnosis is by BP measurement, ECG, urinalysis, and serum electrolyte and creatinine measurements. Treatment is immediate BP reduction with IV antihypertensives.

Signs of target-organ damage include

Damage is rapidly progressive and sometimes fatal.

Hypertensive encephalopathy may involve a failure of cerebral autoregulation of blood flow. Normally, as blood pressure increases, cerebral vessels constrict to maintain constant cerebral perfusion. Above a mean arterial pressure (MAP) of about 160 mm Hg (lower for people who are normotensive whose BP suddenly increases), the cerebral vessels begin to dilate rather than remain constricted. As a result, the very high BP is transmitted directly to the capillary bed with transudation and exudation of plasma into the brain, causing cerebral edema, including papilledema.

Hypertensive urgencies

Severe hypertension (eg, systolic pressure > 180 mm Hg) without target-organ damage (except perhaps grades 1 to 2 retinopathy Hypertensive Retinopathy Hypertensive retinopathy is retinal vascular damage caused by hypertension. Signs usually develop late in the disease. Funduscopic examination shows arteriolar constriction, arteriovenous nicking... read more Hypertensive Retinopathy ) may be considered a hypertensive urgency. Although BP at these very high levels often concerns clinicians, acute complications are unlikely, so immediate BP reduction is not required.

Hypertensive urgencies reference

  • 1. Williams B, Mancia G, Spiering W, et al: 2018 Practice Guidelines for the management of arterial hypertension of the European Society of Hypertension and the European Society of Cardiology: ESH/ESC Task Force for the Management of Arterial Hypertension [published correction appears in J Hypertens 2019 Feb;37(2):456]. J Hypertens 2018;36(12):2284-2309. doi:10.1097/HJH.0000000000001961

Symptoms and Signs of Hypertensive Emergencies

Blood pressure is elevated, often markedly (systolic pressure > 180 mm Hg and/or diastolic pressure 120 mm Hg). Central nervous system symptoms include rapidly changing neurologic abnormalities (eg, confusion, transient cortical blindness, hemiparesis, hemisensory defects, seizures). Cardiovascular symptoms include chest pain and dyspnea. Renal involvement may be asymptomatic, although severe azotemia due to advanced renal failure may cause lethargy or nausea.

Physical examination focuses on target organs, with neurologic examination, funduscopy, and cardiovascular examination. Global cerebral deficits (eg, confusion, obtundation, coma), with or without focal deficits, suggest encephalopathy; normal mental status with focal deficits suggests stroke Overview of Stroke Strokes are a heterogeneous group of disorders involving sudden, focal interruption of cerebral blood flow that causes neurologic deficit. Strokes can be Ischemic (80%), typically resulting... read more Overview of Stroke .

Severe retinopathy Hypertensive Retinopathy Hypertensive retinopathy is retinal vascular damage caused by hypertension. Signs usually develop late in the disease. Funduscopic examination shows arteriolar constriction, arteriovenous nicking... read more Hypertensive Retinopathy (sclerosis, cotton-wool spots, arteriolar narrowing, hemorrhage, papilledema) is usually present with hypertensive encephalopathy, and some degree of retinopathy is present in many other hypertensive emergencies.

Diagnosis of Hypertensive Emergencies

  • Systolic blood pressure > 180 mm Hg

  • Testing to identify target-organ involvement: ECG, urinalysis, serum electrolytes, and creatinine; if neurologic findings, head CT

Testing typically includes ECG, urinalysis, and serum electrolytes, and creatinine.

Patients with neurologic findings require head CT to diagnose intracranial bleeding, edema, or infarction.

Patients with chest pain or dyspnea require and ECG and chest x-ray. ECG abnormalities suggesting acute target-organ damage include acute ischemic changes.

Urinalysis abnormalities typical of renal involvement include red blood cells (RBCs), RBC casts, and proteinuria.

Diagnosis is based on the presence of a very high BP and findings of target-organ involvement.

Treatment of Hypertensive Emergencies

  • Initiate short-acting IV medication (eg, labetalol, clevidipine, esmolol) in the emergency department

  • Admit to intensive care unit (ICU)

  • Goal: 20 to 25% reduction MAP in 1 to 2 hours

Hypertensive emergencies are treated in an ICU; blood pressure is progressively (although not abruptly) reduced using a short-acting, titratable IV medication. Choice of medication and speed and degree of reduction vary somewhat with the target organ involved, but generally a 20 to 25% reduction in MAP over about an hour or two is appropriate, with further titration based on symptoms. Achieving “normal” BP urgently is not necessary. Typical first-line medications include nitroprusside, fenoldopam, nicardipine, and labetalol (see table ). Nitroglycerin alone is less potent.

Table

Oral medications are not indicated because onset is variable and the medications are difficult to titrate. Although short-acting oral nifedipine reduces blood pressure rapidly, it may lead to acute hypotension, which may lead to cardiovascular and cerebrovascular ischemic events (sometimes fatal) and is therefore not recommended.

Clevidipine is an ultra-short-acting (within 1 to 2 minutes), 3rd-generation calcium channel blocker that reduces peripheral resistance without affecting venous vascular tone and cardiac filling pressures. Clevidipine is rapidly hydrolyzed by blood esterases and, thus, its metabolism is not affected by renal or hepatic function. It has been shown to be effective and safe in the control of perioperative hypertension and hypertensive emergencies and was associated with lower mortality than nitroprusside (1 Treatment references A hypertensive emergency is severe hypertension (often defined as systolic blood pressure (BP) ≥ 180 mm Hg and/or diastolic blood pressure ≥ 120 mm Hg) with signs of damage to target organs... read more ). Clevidipine may thus be preferred over nitroprusside for most hypertensive emergencies, although it should be used with caution in acute heart failure with reduced ejection fraction Heart failure with reduced ejection fraction (HFrEF) Heart failure (HF) is a syndrome of ventricular dysfunction. Left ventricular (LV) failure causes shortness of breath and fatigue, and right ventricular (RV) failure causes peripheral and abdominal... read more Heart failure with reduced ejection fraction (HFrEF) as it may have negative inotropic effects. If clevidipine is not available, then fenoldopam, nitroglycerin, or nicardipine are reasonable alternatives.

Fenoldopam is a peripheral dopamine-1 agonist that causes systemic and renal vasodilation and natriuresis. Onset is rapid and half-life is brief, making it an effective alternative to nitroprusside, with the added benefit that it does not cross the blood-brain barrier.

Labetalol is a beta-blocker with some alpha-1-blocking effects, thus causing vasodilation without the typical accompanying reflex tachycardia. It can be given as a constant infusion or as frequent boluses; use of boluses has not been shown to cause significant hypotension. Labetalol is used during pregnancy, for intracranial disorders requiring BP control, and after myocardial infarction. Adverse effects are minimal, but because of its beta -blocking activity, labetalol should not be used for hypertensive emergencies in patients with asthma Asthma Asthma is a disease of diffuse airway inflammation caused by a variety of triggering stimuli resulting in partially or completely reversible bronchoconstriction. Symptoms and signs include dyspnea... read more . Low doses may be used for left ventricular failure if nitroglycerin is given simultaneously.

Nitroprusside is a venous and arterial dilator, reducing preload and afterload; thus, its use is mostly limited to patients with acute decompensated heart failure Heart Failure (HF) Heart failure (HF) is a syndrome of ventricular dysfunction. Left ventricular (LV) failure causes shortness of breath and fatigue, and right ventricular (RV) failure causes peripheral and abdominal... read more Heart Failure (HF) who are hypertensive. It is also used for hypertensive encephalopathy and, with beta-blockers, for aortic dissection Aortic Dissection Aortic dissection is the surging of blood through a tear in the aortic intima with separation of the intima and media and creation of a false lumen (channel). The intimal tear may be a primary... read more Aortic Dissection .The medication is rapidly broken down into cyanide and nitric oxide (the active moiety). Cyanide is detoxified to thiocyanate. However, administration of > 2 mcg/kg/minute can lead to cyanide accumulation with toxicity to the central nervous system and heart; manifestations include agitation, seizures, cardiac instability, and an anion gap metabolic acidosis.

Prolonged administration of nitroprusside (> 1 week or, in patients with renal insufficiency, 3 to 6 days) leads to accumulation of thiocyanate, which can result in lethargy, tremor, abdominal pain, and vomiting. Other adverse effects include transitory elevation of hair follicles (cutis anserina) if BP is reduced too rapidly. Thiocyanate levels should be monitored daily after 3 consecutive days of therapy, and the medication should be stopped if the serum thiocyanate level is > 12 mg/dL (> 2 mmol/L). Because nitroprusside is broken down by ultraviolet light, the IV bag and tubing are wrapped in an opaque covering. Given data showing increased mortality with nitroprusside compared to clevidipine, nitroglycerin, and nicardipine, nitroprusside should not be used when other alternatives are available.

For long-term BP control, nitroglycerin must be used with other medications. The most common adverse effect is headache, occurring in the majority of patients (2 Treatment references A hypertensive emergency is severe hypertension (often defined as systolic blood pressure (BP) ≥ 180 mm Hg and/or diastolic blood pressure ≥ 120 mm Hg) with signs of damage to target organs... read more ); others include tachycardia, nausea, vomiting, apprehension, restlessness, muscular twitching, and palpitations.

Nicardipine, a dihydropyridine calcium channel blocker with less negative inotropic effects than nifedipine, acts primarily as a vasodilator. It is most often used for postoperative hypertension and during pregnancy. It may cause flushing, headache, and tachycardia; it can decrease glomerular filtration rate (GFR) in patients with renal insufficiency.

Treatment references

  • 1. Aronson S, Dyke CM, Stierer KA, et al. The ECLIPSE trials: comparative studies of clevidipine to nitroglycerin, sodium nitroprusside, and nicardipine for acute hypertension treatment in cardiac surgery patients. Anesth Analg 107(4):1110-1121, 2008. doi:10.1213/ane.0b013e31818240db

  • 2. Tfelt-Hansen PC, Tfelt-Hansen J. Nitroglycerin headache and nitroglycerin-induced primary headaches from 1846 and onwards: a historical overview and an update. Headache 49(3):445-456, 2009. doi:10.1111/j.1526-4610.2009.01342.x

Key Points

  • A hypertensive emergency is significantly elevated blood pressure (eg, systolic blood pressure > 180 mm Hg and/or diastolic pressure 120 mm Hg) that causes target-organ damage; it requires intravenous therapy and hospitalization.

  • Target-organ damage includes hypertensive encephalopathy, preeclampsia and eclampsia, acute left ventricular failure with pulmonary edema, myocardial ischemia, acute aortic dissection, and renal failure.

  • Do ECG and urinalysis, measure serum electrolytes and creatinine, and, for patients with neurologic symptoms or signs, obtain head CT.

  • Reduce mean arterial pressure by about 20 to 25% over the first hour using a short-acting, titratable IV medication such as clevidipine, nitroglycerin, fenoldopam, nicardipine, or labetalol.

  • It is not necessary to achieve “normal” blood pressure urgently (especially true in acute stroke).

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

Drugs Mentioned In This Article

Drug Name Select Trade
Normodyne, Trandate
Cleviprex
Brevibloc
NIPRIDE RTU , Nitropress
Corlopam
Cardene, Cardene IV, Cardene SR
Deponit, GONITRO , Minitran, Nitrek, Nitro Bid, Nitrodisc, Nitro-Dur, Nitrogard , Nitrol, Nitrolingual, NitroMist , Nitronal, Nitroquick, Nitrostat, Nitrotab, Nitro-Time, RECTIV, Transdermal-NTG, Tridil
Adalat, Adalat CC, Afeditab CR, Nifediac CC, Nifedical XL, Procardia, Procardia XL
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