A hypertensive emergency is having dangerously high blood pressure that causes complications such as organ failure. Malignant hypertension is one type of hypertensive emergency.

There is disagreement between doctors and diagnostic guides about how to characterize malignant hypertension. Some refer to the sudden onset of symptoms as the main characteristic of malignant hypertension, while others point to a combination of eye damage and very high blood pressure.

Definitions aside, blood pressure higher than 180/120 millimeters of mercury (mm Hg) is a cause for concern. Anyone who has it should receive immediate care.

Below, we describe what a hypertensive emergency is and how it is distinct from benign hypertension, a hypertensive crisis, and hypertensive urgency. We then explore the symptoms, diagnosis, and treatment for dangerously high blood pressure.

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Malignant hypertension is the most severe type of high blood pressure. It qualifies as a hypertensive emergency.

Blood pressure often exceeds 180/120 mm Hg, with the bottom number above 130 or 140 mm Hg. A hypertensive emergency affects the entire body, causing damage to multiple organs and organ systems.

Doctors once defined malignant hypertension as extreme blood pressure that damages the retinas. However, health experts now recognize that the problem can present in a range of ways, and they define it more generally, noting that it can damage multiple organs.

Many people with malignant hypertension do experience eye changes, such as:

  • blurred vision
  • seeing spots
  • sudden blindness
  • bleeding

Typically, malignant hypertension involves diastolic pressure, the bottom number in a reading, exceeding 130 mm Hg. It also tends to damage the eyes, brain, heart, and kidneys.

If a person does not receive treatment for malignant hypertension, the outlook is worse than it is for people who have other forms of high blood pressure. This is especially true for Black people, according to a 2019 report on a long-term study.

The study, which included 168 participants with malignant hypertension, also found:

  • “significant” brain damage in 93% of the participants
  • kidney damage in 55% of the participants
  • blood clots in small blood vessels in 15% of the participants
  • enlargement of the heart’s left ventricle in 82% of the participants
  • decreased pumping of the heart in 56% of the participants

Normal blood pressure usually ranges from 90/60 mm Hg to 130/80 mm Hg.

Benign hypertension is a less dangerous form of high blood pressure, which doctors may also call essential hypertension. It does not stem from a specific medical condition, though lifestyle factors such as smoking, eating too much salt, and obesity may play a role.

Unlike malignant hypertension, benign hypertension is not a medical emergency. It is a chronic condition, and despite its name, it can cause harm over time. For example, benign hypertension may affect the kidneys by thinning the renal cortex. It may also cause protein to leak into urine.

However, benign hypertension does not cause significant, immediate kidney damage, changes to the eyes, or widespread organ damage, as seen in hypertensive emergencies such as malignant hypertension.

If a person with benign hypertension does not receive treatment for it, it may lead to a hypertensive emergency. However, as many as 60% of people who have experienced a hypertensive emergency may have no history of benign hypertension.

A “hypertensive crisis” is an umbrella term that includes cases of hypertensive urgency and hypertensive emergency, such as malignant hypertension. While about 30% of adults in the United States have hypertension, 2% or fewer will experience a hypertensive crisis.

The difference between hypertensive urgency and a hypertensive emergency is that no organ damage occurs in cases of urgency, despite a severe elevation in blood pressure. Organ damage is a defining feature of a hypertensive emergency.

A rapid increase in blood pressure can cause hypertensive urgency or an emergency, even when blood pressure is still within the normal range. This can even involve diastolic blood pressures as low as 100–110 mmHg. But a person with hypertensive urgency or an emergency typically has blood pressure higher than 180/120 mm Hg.

Although technically the term “hypertensive crisis” includes cases of hypertensive urgency and emergency, doctors sometimes only use the term for hypertensive emergencies, such as cases of malignant hypertension. This is often true if brain dysfunction is involved, causing loss of consciousness, confusion, seizure, or stroke.

Hypertensive emergencies, including malignant hypertension, are life-threatening and require immediate treatment.

A hypertensive emergency is a common complication of benign hypertension. This means that people with high blood pressure have an increased risk of hypertensive emergencies, such as malignant hypertension.

Other causes of malignant hypertension include:

Symptoms of a hypertensive emergency can include:

  • chest pain
  • a headache
  • mood or personality changes
  • stomach pain
  • nausea or vomiting
  • back pain
  • breathing difficulty
  • trouble seeing, including sudden blindness
  • a decrease in urination
  • arm or leg weakness
  • confusion
  • seizures
  • loss of consciousness

These symptoms may indicate organ damage and may also resemble those of other medical conditions, such as heart and kidney diseases. For this reason, it is important to receive medical attention right away. A person should not self-diagnose.

Blood pressure above 180/120 mm Hg may be the first sign of a life threatening emergency. If either number exceeds this, seek immediate medical care. This might involve calling 911 or the local emergency number.

A person should contact a doctor if they:

  • have high blood pressure, of 130/80 mm Hg or higher, and no other symptoms
  • want to stop taking blood pressure medication or their medication stops working
  • have new symptoms related to high blood pressure, such as seeing spots

After receiving urgent care for a hypertensive emergency, continue seeing a doctor. This can reduce the risk of long-term, serious complications and allow the doctor to track symptoms over time.

Diagnosing malignant hypertension begins with taking a medical history and considering the symptoms. This can help a doctor determine which tests may detect organ failure. Tests that a doctor might recommend include:

  • an electrocardiogram, called an EKG, which measures electrical pulses in the heart
  • a chest X-ray to check the health of the heart and lungs
  • blood work to look for signs of organ failure, infection, and certain chronic diseases
  • urine screening to look for signs of kidney failure
  • CT, MRI, and other imaging scans to check for damage to the brain and aorta, for example
  • ultrasounds, which may include echocardiography, to check how the heart is pumping

Lowering blood pressure too quickly can damage the blood flow to organs accustomed to functioning at high blood pressure levels. For this reason, doctors usually administer drugs that gradually lower a person’s blood pressure to around 160/110 mm Hg within the first 24 hours.

There are exceptions to this rule. For example, if a person has an aortic dissection, it is important to lower their blood pressure quickly.

Medications that a doctor might use include:

  • labetalol
  • sodium nitroprusside
  • nicardipine
  • esmolol
  • nitroglycerin
  • clevidipine

Usually, a person receives the medication through an intravenous (IV) line in a vein. A doctor may also give fluids through the IV.

The person needs to stay in the hospital for monitoring until their blood pressure drops and a doctor can identify the cause of the hypertensive emergency. They may recommend additional treatments, and they may refer the person to a specialist for care.

A hypertensive emergency can be life threatening, and it requires immediate care. If a person receives treatment in time, there is a possibility of recovery.

It is crucial not to delay treatment for dangerously high blood pressure. This usually involves either figure in a blood pressure reading being higher than 180/120 mm Hg.

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