What does a sudden drop in blood pressure mean?


A sudden drop in blood pressure can occur for a number of reasons, some of which may be accidental and not a real danger, while others may be a sign of a life-threatening condition.

José Luis Peláez Inc. / Fake images

A sudden drop in blood pressure is often recognized by symptoms ranging from mild dizziness and fatigue to severe heart rhythm disturbances and respiratory failure.

Although low blood pressure (hypotension) is easily diagnosed with a blood pressure cuff (sphygmomanometer), the underlying cause of sudden and severe falls may require extensive investigation, including physical examination, laboratory tests, heart monitoring, and blood pressure studies. images.


Blood pressure is measured in millimeters of mercury (mm Hg). Hypotension is generally defined as a systolic (upper) value of 90 mm Hg. Art. And the (lowest) diastolic value is 60mm Hg. Normal blood pressure is closer to 120/80 mm Hg .

In general, the lower and faster your blood pressure falls, the greater your risk and the severity of your symptoms. The degree of pressure drop also plays a role.

If, for example, you have high blood pressure ( hypertension ) and your blood pressure suddenly drops below 90/60 mmHg.

Common symptoms

A sudden drop in blood pressure can be a symptom, as decreased blood flow deprives the body of oxygen and nutrients it needs to function. Common signs include :

  • Daze
  • Dizziness
  • Nausea
  • Fatigue
  • Drowsiness
  • Lack of concentration
  • Blurry vision
  • Fainting

Many other symptoms may be involved, such as chest pain, shortness of breath, irregular heartbeat, hives, fever, indigestion, and vomiting, but these are generally associated with the condition that caused the decline in the first place .

Severe symptoms

Severe hypotension can severely deprive the brain and vital organs of oxygen and nutrients, leading to shock . Shock can progress rapidly and usually presents with:

  • Extreme weakness
  • Extreme anxiety
  • Cardiopalmus
  • Weak pulse
  • Rapid, shallow breathing
  • Profuse sweating
  • Increased thirst
  • Clammy skin
  • Confusion

Call 911 or go to the nearest emergency room if signs of shock appear. Left untreated, shock can lead to permanent organ damage, cardiac arrest , and even death.


Sudden hypotension can be classified for underlying reasons, some of which may overlap, making diagnosis difficult.


Hypovolemia , a term used to describe reduced blood volume, is the most common cause of hypotension. This occurs as a result of excessive fluid loss or insufficient fluid intake .

Common causes of hypovolemia include:

  • Dehydration
  • Fasting or starvation
  • Severe diarrhea or vomiting
  • Heatstroke
  • Overuse of diuretics (“ water pills '')
  • Renal insufficiency
  • Severe pancreatitis (causing fluid to leak into the abdomen)
  • Loss of blood leading to hemorrhagic shock .

Hypovolemic shock occurs when, for whatever reason, you lose more than 20% of your blood volume. Loss at this level prevents the heart from pumping enough blood throughout the body .

Decreased cardiac output.

Even if blood volumes are normal, there are conditions that can reduce the body's ability to pump blood. A condition known as decreased cardiac output can result from heart failure, endocrine (hormonal) dysfunction, and certain medications. Sudden changes in cardiac output can often present with symptoms of acute hypotension.

Causes of decreased cardiac output include .


Vasodilation describes the sudden expansion of blood vessels due to chemical, neurological, or immune stimuli. As the blood vessels expand, the blood pressure will drop simultaneously with the increase in the girth of the blood vessels.

Common causes of vasodilation include :

  • Vasodilator drugs: such as calcium channel blockers, angiotensin II receptor blockers, nitroglycerin, nitrous oxide, rogaine (minoxidil), and viagra (sildenafil).
  • Dysautonomia – A condition in which the autonomic nervous system is disrupted and affects the heart, bladder, intestines, blood vessels, and other organs.
  • Sepsis : can cause septic shock.
  • Anaphylaxis – A severe whole-body allergy that can lead to anaphylactic shock.
  • Acidosis: increased acidity of the blood.
  • Injury to the brain or spinal cord – May cause neurogenic shock.

Hypotensive syndromes.

Hypotensive syndromes are interrelated phenomena that cause a sudden drop in blood pressure. Some of them happen on their own without any illness or long-term consequences. Others arise from disease or other external factors.

Hypotensive syndromes often appear suddenly with obvious and sometimes dramatic symptoms, including severe dizziness and loss of consciousness.

Some common hypotensive syndromes include:

  • Neurogenic orthostatic hypotension (NOH) occurs when a change in body position, such as getting up from a chair or bed, causes a sharp drop in blood pressure. NOH is caused by an underlying neurological disease that affects the autonomic nervous system. It is common in neurogenerative disorders such as Parkinson's disease and Lewy body dementia , as well as diabetic nerve damage .
  • Orthostatic hypotension (OH) has the same symptoms as NOH, but is caused by non-neurological causes such as decreased cardiac output, severe vasodilation, and chronic use of diuretics, tricyclic antidepressants, and antihypertensive drugs. OH and NOH can also be collectively referred to as postural hypotension .
  • Supine hypotensive syndrome occurs later in pregnancy when the baby's weight presses on the body's two largest blood vessels, the aorta and the inferior vena cava, reducing blood flow to the heart .
  • Postprandial hypotension occurs after a meal, when blood is sent to the intestines to aid digestion, temporarily depriving the brain of blood and oxygen. It is most common in the elderly and usually occurs between 30 and 75 minutes after eating .
  • Vasovagal syncope is an overreaction to certain triggers, such as seeing blood or extreme emotional stress, causing a sudden drop in blood pressure and fainting ( fainting ). It is caused by over-activation of the vagus nerve , which carries nerve signals from the heart, liver, heart, lungs, and intestines to the brain .
  • Situational reflex syncope affects the vagus nerve, but occurs when physical stress is placed directly on the nerve. Examples include straining during a bowel movement, lifting heavy objects, or standing in one place for too long. Urination after taking a vasodilator such as Cialis (tadalafil) can also cause reflex fainting .
  • Carotid syncope is similar to supine hypotension in that it involves compression of another major artery, the internal carotid artery in the neck. Wearing a tight collar, shaving, or turning your head can cause a sudden drop in blood pressure, especially in the elderly or people with carotid stenosis .


Hypotension can be easily diagnosed with a blood pressure cuff called a tonometer. What the sphygmomanometer cannot detect is the cause of the sudden drop in blood pressure.

To do this, your doctor will need to review your medical history, family history, current symptoms, and medications to list possible causes. Between examinations and tests, the doctor may prescribe :

  • Valsalva maneuver: An office test used to diagnose orthostatic hypotension, in which you blow forcefully through pursed lips to see how it affects your blood pressure and heart rate.
  • Blood tests: These are used to detect conditions associated with acute hypotension, such as diabetes, anemia, hypoglycemia, thyroid problems, kidney failure, and hormonal imbalances.
  • Urinalysis – Used when kidney failure is suspected.
  • Electrocardiogram (ECG): measures the electrical activity of the heart to detect rhythm disturbances, heart failure, and other cardiovascular diseases.
  • Echocardiograms – Uses sound waves to create video images of the heart to detect structural defects, such as a leaking heart valve.
  • Imaging tests : X-rays, computed tomography (CT) , or magnetic resonance imaging (MRI) , which are used to look for internal bleeding, structural heart problems, kidney problems, or brain or spinal cord injuries.
  • Tilt Table Test – Measures heart function and blood pressure when the body is tilted at different angles on an adjustable table. It is used primarily to diagnose postural hypotension.
  • Stress test: measures a person's heart rate and blood pressure while running on a treadmill or pedaling an exercise bike. It is used primarily to diagnose coronary artery disease.

Watch out

Treatment of acute hypotension depends on the underlying cause. If the condition is not a medical emergency, you should sit or lie down immediately and raise your legs above the level of your heart. If you are dehydrated, you should make up for the fluid loss and seek immediate medical attention if symptoms are severe.

If there is hypovolemic or hemorrhagic shock, you may be given intravenous (IV) saline or a blood transfusion . Septic shock may require intravenous antibiotics, while anaphylactic shock almost always requires adrenaline (epinephrine) .

If hypotension is associated with severe vasodilation or decreased cardiac output, medications such as vasodilators ( such as midodrine ) or cardiac stimulants (such as digitalis) may be prescribed to improve cardiac function and cardiac output .

People with severe postural hypotension may benefit from the anti-inflammatory steroid fludrocortisone .

Compression socks are often prescribed for people with orthostatic hypotension to prevent blood from pooling in the legs. Wearing them holds more blood in the upper body.

Acute hypotension is usually treated successfully. On the other hand, the underlying cause may require extensive treatment and the help of a specialist cardiologist, neurologist, or endocrinologist.

Get the word of drug information

It is important not to ignore the signs of hypotension, no matter how minor. Hypotension can be something you were just born with or something you can control by properly consuming water. In other cases, it could be a sign of something more serious.

This is especially true if the fall is sudden and violent. Seeing your doctor and determining the cause of your acute hypotension can help you get proper treatment and prevent long-term damage to your health.

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