Hypertension V - Severe High Blood Pressure and Hypertensive Crisis

hypertension; severe high blood pressure; hypertensive crisis; types of hypertension; risk factors of hypertension; prevention of primary/essential hypertension
Medical Tutors Limited
September 13, 2023

11:01 AM

Once hypertension or high blood pressure has been diagnosed, and treatment does not commence immediately, it can lead to severe high blood pressure or crisis

If high blood pressure is not controlled or well managed, it can lead to a hypertensive crisis. A hypertensive crisis is a sudden, quick, and severe increase in blood pressure. It can be described among patients with systolic blood pressure greater than 180mmHg and diastolic blood pressure greater than 120mmHg. It can cause symptoms such as headache, chest pain, nausea/vomiting, or dizziness, shortness of breath, back pain, numbness/weakness, etc.

A hypertensive crisis is a medical emergency that can lead to a heart attack, stroke, or other life-threatening health problems. Severely high blood pressure can damage blood vessels and body organs, including the heart, brain, kidneys, and eyes. During a hypertensive crisis, the heart may be unable to pump blood effectively.

Hypertensive crisis is classified into two types:

  1. Hypertensive Urgency
  2. Hypertensive Emergency

Who Can Have Hypertensive Crisis and What Causes It?

Although hypertensive crisis affects only a small amount of people with high blood pressure (about 1% - 3%,) including children and adults, it is more common in younger adults. Also, it is more common among Blacks, men, and people who smoke.

Causes of a hypertensive crisis include:

  • Forgetting to take blood pressure medication
  • Suddenly stopping certain medications, such as clonidine
  • Medication interactions
  • Tumor of the adrenal gland (pheochromocytoma)

Hypertensive Urgency

This is when the blood pressure is abnormally high i.e., 180/120mmHg, but there are no signs of damage to the body’s organs.

Clinical Features of Hypertensive Urgency

There are no symptoms for hypertensive urgency, but rather an extreme rise in blood pressure i.e., 180/120mmHg or greater and there is no organ damage.

Treatment of Hypertensive Urgency

Hypertensive urgency does not need inpatient care or intravenous blood pressure medications. Instead, blood pressure medications are taken by mouth. These drugs gradually decrease blood pressure until it reaches a safe range.

Hypertensive Emergency

This is when a rise in blood pressure is 180/120mmHg or greater and with life-threatening damage to the body’s organs.

What Causes a Hypertensive Emergency?

Some health conditions increase one chance of having a hypertensive emergency. These include:

  • Kidney disorders or kidney failure
  • Use of drugs such as cocaine, amphetamines, birth control pills, or monoamine oxidase inhibitors (MAOIs)
  • Pregnancy
  • Preeclampsia, which is common after 20 weeks gestation, but can sometimes occur earlier.
  • Renal artery stenosis, which is a narrowing of the arteries of the kidneys
  • Not taking the medication for high blood pressure or sudden withdrawal of certain antihypertensive drugs like clonidine

Clinical Features of Hypertensive Emergency

When the blood pressure in a person tends to be extremely high above 180/120mmHg, and some organs in the body seem to be affected, the commonest hypertensive emergencies are hypertensive encephalopathy and eclampsia.

Hypertensive Encephalopathy

Hypertensive encephalopathy is a manifestation of a hypertensive emergency. A hypertensive encephalopathy is a life-threatening condition where ongoing target-organ damage occurs due to markedly elevated blood pressure. Patients with hypertensive encephalopathy require hospital admission and administration of parenteral antihypertensive drugs for immediate reduction of blood pressure.

Symptoms of hypertensive encephalopathy vary from patient to patient. It includes the gradual onset of headache, nausea, and vomiting, followed by neurologic symptoms such as restlessness, drowsiness, confusion, and possibly epileptic event. These symptoms are manifested over several days in various combinations and degrees and may progress to stupor, coma, and death if left untreated.  If hypertension is treated promptly, the symptoms of encephalopathy are usually reversible.

Headache is the, most common symptom, occurring in greater than 75% of hypertensive encephalopathy patients. The gradual onset of morning headaches accompanied by nausea and vomiting is typical.

Visual disturbance is Common, occurring in 4 out of 11 cases symptoms range from nonspecific blurring to visual field defects, Prosopagnosia, and even cortical blindness.


Pregnant patients who develop elevations in blood pressure during pregnancy, immediately before, or after delivery do have a hypertensive emergency called eclampsia. The presence of a systolic pressure greater than 169 mmHg or a diastolic pressure greater than 109 mmHg in a pregnant woman with features of hypertensive encephalopathy is considered a hypertensive emergency that requires immediate pharmacologic management. This emergency is called eclampsia.

Eclampsia is a rare but serious complication of preeclampsia. Preeclampsia is a disorder of pregnancy in which a person who is pregnant has high blood pressure and protein in their urine. Eclampsia is when a person with preeclampsia develops seizures (convulsions) during pregnancy. These seizures are episodes of shaking, confusion, and disorientation caused by abnormal brain activity. Also, these seizures can cause confusion and disorientation or put the pregnant person in a coma. In some cases, it can lead to stroke or death.

Eclampsia typically occurs after the 20th week of pregnancy. It is rare and affects less than 3% of people with preeclampsia. Eclampsia can cause complications during pregnancy and requires emergency medical care.

In pregnant patients, the clinical features vary but may include visual field defects, severe headaches, seizures, altered mental status, severe right upper quadrant abdominal pain, congestive heart failure, and Oliguria. In the vast majority of cases, this process can only be terminated by delivery.

Treatment of Hypertensive Encephalopathy and Eclampsia

Hypertensive Encephalopathy

In patients with hypertensive encephalopathy, blood pressure should be lowered within minutes to decrease morbidity. The best agent to use and the degree to which blood pressure should be acutely reduced depends on several variables including the patient's pre-morbid blood pressure, duration of hypertensive emergency, and other medical diseases.

The primary treatment for this condition involves administering antihypertensive drug therapy to lower the MAP by 10% to 15% during the first hour. The MAP should not be lowered by more than 25% of the original baseline MAP within the first day of treatment.

Certain drug medications are used in the treatment of hypertensive encephalopathy, and they include:

  • Labetalol - intravenous
  • Nicardipine - intravenous
  • Esmolol - intravenous
  • Fenoldopam - intravenous
  • Nitroglycerin


In patients with eclampsia, the recommended treatment is the delivery of the baby and placenta. Allowing the pregnancy to continue while the mother has eclampsia can result in complications. The doctor will consider the severity of the disease and how mature the baby is when recommending the timing of delivery. Medications and monitoring will help keep blood pressure within a safer range until the baby is mature enough to deliver.

Also, medications to prevent seizures, called anticonvulsant drugs, may be necessary.

Prevention of Hypertensive Crisis

Some cases of hypertensive crisis can be prevented. If one has high blood pressure, it is important to check blood pressure regularly. It is also important to take all prescribed medications without missing any doses. Maintain a healthy lifestyle by eating a healthy diet that is low in salt and fat, exercising regularly, managing stress, losing weight, limiting alcohol intake, and quitting smoking. Also, treat any ongoing health conditions that may put one at risk for a hypertensive emergency. Seek immediate treatment if one develops any symptoms.

Latest News