Signs of a Hypertensive Emergency and When to Call 911

A hypertensive emergency is a potentially life-threatening rise in blood pressure defined by a systolic pressure over 180 or a diastolic pressure over 120. Also known as malignant hypertension, a hypertensive emergency can cause shortness of breath, confusion, blurred vision, and seizures. If left untreated, it can start to damage organs, including the brain, heart, and kidneys.

A hypertension emergency requires treatment in an intensive care unit (ICU) of a hospital, often using intravenous beta-blockers like Brevibloc (esmolol) to quickly lower blood pressure.

This article describes the symptoms, causes, and treatment of a hypertensive emergency, including the risk of death from untreated malignant hypertension.

When Should You Go to the ER for a Hypertensive Emergency?

Blood pressure is measured in millimeters of mercury, or mmHg. In adults, hypertension (high blood pressure) is defined by a systolic (upper) blood pressure reading of 120 mmHg or greater and a diastolic (lower) blood pressure reading of 80 mmHg or greater.

Hypertension is considered malignant with systolic readings greater than 180 mmHg or diastolic readings greater than 120 mmHg.

Sustained levels this high can start to damage blood vessels and organs, leading to an irreversible condition called hypertension-mediated organ damage (HMOD), complications of which may include:

• Unstable angina (chest pains)
• Pulmonary edema (fluid in the lungs)
• Optic nerve damage
• Acute kidney failure
• Heart failure
• Heart attack
• Aortic aneurysm (a bulge in a major blood vessel servicing the heart)
• Hemorrhagic stroke (stroke caused by a ruptured blood vessel in the brain)

Can a Hypertensive Emergency Kill You?

A study published in the Journal of the American Heart Association reported that 9.9%—or roughly one out of every 10 people—die of a hypertensive emergency while in the hospital.

What Are the Signs of a Hypertensive Emergency?

Hypertension doesn't generally cause any symptoms. The same is not true with a hypertensive emergency in which dangerously high blood pressure can lead to profound symptoms such as:

• Headaches
• Blurred vision
• Increasing confusion
• Severe anxiety
• Nausea and vomiting
• Increasing shortness of breath
• Transient loss of vision
• Swelling of the feet, lower legs, and ankles
• Blood in urine
• Seizures
• Loss of consciousness

What Can Cause a Hypertensive Emergency?

The majority of hypertensive emergencies occur in people diagnosed with chronic hypertension. Failure to take your high blood pressure medications or suddenly stopping treatment is one of the most common causes of a hypertensive emergency.

A class of drugs called sympathomimetics can elevate blood pressure excessively, particularly those with uncontrolled hypertension. These include commonplace drugs like:

• Epinephrine used to treat anaphylaxis
• Asthma bronchodilators
• Decongestants containing pseudoephedrine
• Appetite suppressants
• Stimulants used to treat attention-deficit/hyperactivity disorder (ADHD)
• Cocaine and methamphetamine

Certain drug-drug interactions can lead to malignant hypertension, while medical conditions like advanced chronic kidney disease, certain endocrine (hormonal) disorders, and preeclampsia (high blood pressure during pregnancy) can trigger a hypertensive emergency.

Oftentimes, multiple factors are involved.

How Common Is a Hypertensive Emergency?

A hypertensive emergency is an uncommon event. Studies suggest that only 1% to 3% of people with hypertension will experience a hypertensive emergency during their lifetime.

Symptoms and Complications of Heart Failure

How a Hypertensive Emergency Is Diagnosed

Blood pressure is measured with a device called a sphygmomanometer that is placed on your arm.

If you are having a hypertensive emergency, your blood pressure will be checked in both arms. This is because variations of blood pressure in each arm of 10 mmHg and 15 mmHg are indicative of arterial blockage somewhere in the body that can lead to a stroke or heart attack.

After the initial readings, you would be placed on a continuous blood pressure monitor to keep constant track of increases or decreases in your blood pressure.

To characterize your risk of HMOD, other tests and procedures may be ordered, including:

• Blood tests, including kidney function tests and blood clotting tests
• Chest X-ray to check the pulmonary edema or bleeding
• Urinalysis to check for blood in urine and other kidney problems
• Electrocardiogram (ECG) to check for changes in heart rhythms
• Computed tomography (CT) scan of the heart and brain to check for ruptures and bleed

What Is the First-line Treatment for a Hypertensive Emergency?

Treating hypertensive emergencies may require admission into the ICUs. Medications aimed at reducing blood pressure can be administered orally (through the mouth), sublingually (under the tongue), or intravenously (through a vein).

The goal of therapy is to reduce blood pressure by 20% to 25% during the first hour. Drugs commonly used for this include:

• Adalat (nifedipine
• Brevibloc (esmolol)
• Cardine (nicardipine)
• Nitroglycerin
• Trandate (labetalol)

The emergency room team won't want to reduce your blood pressure too quickly as this could lead to shock (another condition in which multi-organ failure may occur due to a sudden, severe drop in blood pressure).

Summary

A hypertensive emergency, also known as malignant hypertension, occurs when your blood pressure is high enough to cause organ damage and even death. It is diagnosed when your systolic pressure is over 180 mmHg and/or the diastolic pressure is over 120 mmHg. A hypertensive emergency is treated in the ICU of a hospital with rapid-acting blood pressure medications.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

1. Centers for Disease Control and Prevention. High blood pressure.
2. Benken ST. Hypertensive emergencies. Medical Issues in the ICU. 2018; 7-30.
3. Siddiqi TJ, Usman MS, Rashid AM, et al. Clinical outcomes in hypertensive emergency: a systematic review and meta-analysis. J Am Heart Assoc. 2023 Jul 18;12(14):e029355. doi:10.1161/JAHA.122.029355
4. Assarzadegan F, Asadollahi M, Hesami O, Aryani O, Mansouri B, Beladi moghadam N. Secondary headaches attributed to arterial hypertension. Iran J Neurol. 2013;12(3):106-10.

By Brandon Peters, MD
Dr. Peters is a board-certified neurologist and sleep medicine specialist and is a fellow of the American Academy of Sleep Medicine.

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