What Is Malignant Hypertension?

Malignant hypertension (MHT) is a severe form of high blood pressure. It is characterized by a sudden spike in blood pressure and acute organ damage. The incidence of MHT in the United States is highest among Black Americans, current and former smokers, and people with a history of renal artery stenosis (narrowing in one or more arteries carrying blood to the kidneys). 

Malignant hypertension is a medical emergency. It can lead to permanent central nervous system (CNS), cardiovascular, and renal damage if left untreated.

An episode may be categorized as a hypertensive emergency when systolic blood pressure (the top number) is 180 millimeters of mercury (mmHg) or higher, diastolic blood pressure (the bottom number) is 120 mmHg or higher, and there is the presence of end-organ damage.

Severe and life-threatening complications may be avoided with prompt medical treatment aimed at gradually reducing blood pressure levels.

Malignant Hypertension Symptoms

Symptoms of malignant hypertension include:

• Headache
• Changes in vision, such as blurred or double vision
• Shortness of breath
• Change in mental status, such as stupor, agitation, anxiety, confusion, decreased alertness, decreased ability to concentrate, fatigue, restlessness, or sleepiness
• Chest pain (crushing or pressure sensation)
• Cough
• Nausea or vomiting
• Numbness or weakness of the arms, legs, face, or other areas
  
• Reduced urine output

In severe cases, untreated malignant hypertension can lead to:

• Permanent heart damage, such as heart attack, aortic dissection (a tear in the aorta), chest pain (angina), and arrhythmias (irregular heartbeat) 
• Paralysis or trouble finding words due to a stroke
• Seizure
• Blood in urine due to kidney failure
• Permanent vision loss
• Swelling of the brain (encephalopathy)

Causes

MHT is relatively rare, occurring in less than 1% of people with hypertension. The most common cause of MHT is uncontrolled hypertension, but the following conditions may also lead to MHT:

• Collagen vascular diseases (conditions that cause inflammation in the connective tissues), such as systemic lupus erythematosus and systemic sclerosis
• Kidney failure or some other type of renal disorder, such as narrowing of the renal arteries (renal artery stenosis)
• Spinal cord injuries
• Tumor of the adrenal gland
• Use of certain medications, including birth control pills and some antidepressants
• Use of recreational drugs, such as cocaine and amphetamines 
• High blood pressure in pregnancy (preeclampsia) 
• Coarctation of the aorta (narrowing that is present from birth)

Diagnosis

Diagnosis of malignant hypertension starts with a healthcare provider taking a detailed history and vital signs. A focused physical examination will include taking the blood pressure in both arms, a neurological examination, and a fundoscopic eye examination.

If signs of neurological damage are present, a computed tomography (CT) scan or magnetic resonance imaging (MRI) of the brain may be used to look for signs of damage.

If you have signs of cardiac dysfunction, such as chest pain or shortness of breath, your healthcare provider may perform a chest X-ray, followed by a chest CT or MRI, to check for aortic dissection (a tear in the wall of the aorta).

An electrocardiogram (EKG or ECG), echocardiogram, and cardiac biomarkers can help check for arrhythmias or heart damage. 

Blood urea nitrogen (BUN) and creatinine levels may be measured to assess kidney damage. A urinalysis is a quick and widely available way to check for protein or blood in your urine, which are signs of renal damage.

While there is some debate on the exact definition and diagnostic criteria for MHT, generally, a diagnosis of malignant hypertension can be made in the presence of very high blood pressure readings in one or both arms (usually 180/120 mmHg) and any sign of acute damage in one or more organs, such as flame-shaped hemorrhages or soft exudates on your eye exam.

Still, treatment is usually initiated by your healthcare provider if there is a high degree of clinical suspicion for MHT, even if blood pressure is not over 180/120 mmHg or there are no obvious signs of retinal hemorrhage, papilledema, or exudates on fundoscopy. 

Treatment

MHT is a medical emergency. Treatment should be administered in a hospital under medical supervision. Referral to specialists, surgery, dialysis, and even kidney transplant may be needed. Hypertensive medications must be given via an intravenous (IV) line to take effect faster than oral medication.

Medical management to gradually reduce blood pressure is the gold standard treatment for malignant hypertension. The best hypertensive treatment for you will be based on the cause of your MHT.

Intravenous (IV) beta-blockers (labetalol, propranolol, or esmolol) and calcium channel blockers (nicardipine and clevidipine) are first-line treatments for MHT when detected in its early stages. IV nitroglycerin may be used in more severe cases based on its rapid onset of action.

Nitroprusside may be used in cases of MHT that present with intracranial bleeding, swelling of the brain (encephalopathy), heart attack, or aortic dissection. Hydralazine may be used in hypertensive cases in pregnancy (preeclampsia).

Reducing your blood pressure under the guidance of a medical professional is especially important because an overly aggressive approach can lead to a harmful reduction in organ blood flow (hypoperfusion) and more serious organ damage.

For most hypertensive emergencies, mean arterial pressure should be reduced gradually, by approximately 10% to 20% in the first hour and by a further 5% to 15% over the next 23 hours.

Prognosis

Those who receive a prompt diagnosis and appropriate antihypertensive treatment generally have a good prognosis. The time from diagnosis to treatment is critically important because the disease tends to progress rapidly toward permanent end organ damage.

Untreated MHT has a mortality rate of 80% within two years. Even with treatment, MHT can be deadly, with one study reporting a nearly 7% hospital mortality rate and a 37% readmission rate within 90 days across 25 U.S. hospitals.

Summary

Malignant hypertension (MHT), the most severe form of hypertension, is a phenomenon characterized by a sudden spike in blood pressure (usually above 180/120 mmHg) and acute damage in one or more organs. It is a medical emergency that should be treated in a hospital.

A Word From Verywell

Survival rates have improved dramatically for MHT due to advances in clinical treatment. Still, the key to avoiding serious medical complications is to receive medical treatment as soon as possible if you are experiencing any of the aforementioned symptoms.

Even after successful treatment, you may need to see your healthcare provider for follow-up appointments to screen for secondary hypertension, help catch complications, and mitigate any lingering issues.

MHT can affect any person at any age. But smokers, Black Americans, and people with a history of drug use or kidney damage are more likely than others to get MHT. They should check with a healthcare provider regularly to manage their blood and discuss lifestyle changes (like quitting smoking) that can help reduce the risk of MHT recurrence.