healthy people, the systolic pressure varies between 90 and 120 millimeters
of mercury (mm Hg).
is produced by the pumping of blood through the heart and arteries
that provide resistance to the passage of the blood.
is measured by two figures, a higher (systolic) represents the pressure
in the arteries when the heart contracts and pumps blood into them,
and a lower number (diastolic) represents the pressure in the arteries
when the heart muscle relaxes after contracting.
refers to a blood pressure that is too low and causes a series of
signs and symptoms. When blood pressure is too low, there is not enough
blood supply to organs and tissues, they are not getting enough oxygen
and nutrients and can not function properly.
is defined primarily by signs and symptoms of decreased blood flow,
rather than measuring blood pressure.
a person may have a blood pressure of 90/50 and not show symptoms
of hypotension (eg, athlete), and therefore not considered to have
hypotension, whereas a person with normal blood pressure of 130 /
80 may develop a symptomatic hypotension if the pressure drops to
effects of hypotension
pressure does not necessarily pose a risk to health.
with low blood pressure have a lower risk of kidney disease and heart
disease. Athletes, people who exercise regularly, people with a healthy
weight and non-smokers tend to have lower blood pressure than other
Therefore, low blood pressure is desirable as long as it is not low
enough to cause symptoms and damage organs.
of hypotension or low blood pressure
When blood pressure is not high enough so you can get blood to the
body's organs, they do not receive an adequate supply of oxygen and
nutrients, so they do not work properly and may be damaged.
if the brain does not receive an adequate supply of oxygen and nutrients,
the person may feel dazed, dizzy or even faint.
When there is not enough blood reaching the coronary arteries (which
supply blood to the heart muscle), a person can develop chest pain
(angina) or myocardial infarction.
When there is not enough blood reaching the kidneys, they do not properly
dispose of body waste products such as urea and creatinine, so the
blood levels of these substances increase.
occurs when blood pressure remains low, resulting in rapid failure
of organs such as kidneys, liver, lungs or brain. For example when
there is severe bleeding, with great loss of blood.
When a person is sitting or lying down and up, symptomatic hypotension
may occur. This happens because when standing, blood pools in the
lower body and this can cause pressure to drop momentarily.
pressure is already low, the fact of standing up can make the blood
pressure to come down even more to the point of producing symptoms.
This is called orthostatic hypotension. Healthy people make up this
quickly so that the pressure returns to normal soon.
of low blood pressure
main causes of hypotension are the diseases that reduce blood volume
or the amount of blood pumped by the heart and drugs.
Hypotension due to reduced blood volume
can occur in people with diarrhea who lose large amounts of water
in your stool, especially when associated with vomiting. Dehydration
can also occur due to repeated vomiting.
causes of dehydration include exercise, sweating, fever and heat stroke.
People with mild dehydration may experience only thirst and dry mouth.
A moderate to severe dehydration may cause orthostatic hypotension.
Severe dehydration can cause shock, kidney failure, confusion, acidosis,
coma and even death.
Moderate or severe bleeding
of blood caused by bleeding can lead to hypotension.
bleeding is severe, it can produce a shock quickly.
Severe swelling of internal organs
pancreatitis is an example. The liquid passes from the blood to the
inflamed pancreas and abdominal cavity lowers the blood volume.
Hypotension due to heart disease.
Weakened heart muscle
can cause failure of the heart, so reducing the amount of blood can
weakness of the myocardium may occur due to extensive myocardial infarction
or multiple small strokes that make the infarcted zone inoperable.
Other causes include: certain medications toxic to the heart, infections
of the myocardium (heart muscle) and cardiac valve disease.
an inflammation of the pericardium (the membrane that surrounds the
heart). Pericarditis can cause a buildup of fluid in the pericardium
and around the heart, preventing the heart from pumping blood properly.
when a blood clot in a vein travels to the heart and lungs, blocking
the flow of blood from the lungs into the left ventricle, so reducing
the amount of blood the heart can pump.
of a slowing heart rate. The resting heart beats at a rate of between
60 and 100 beats per minute. When the pressure drops below 60 there
is a bradycardia which may produce hypotension, dizziness and fainting.
high heart rate can also lead to hypotension. For example, when an
atrial fibrillation ocurrs, which is characterized by rapid and irregular
electrical discharge that starts from the heart muscle, rather than
from the SA node (sinoatrial node) and causes the ventricles to contract
very quickly and, generally, irregularly. By shrinking so rapidly,
they do not have time to fill, so the amount of blood pumped is limited.
Drugs that may cause hypotension
- Medications such as beta blockers, calcium channel or lanoxin.
- Drugs used to treat hypertension.
- Diuretics, because they can decrease blood volume.
- Alcohol and narcotics.
Other disorders that may cause hypotension
a common response by which a healthy person may develop temporary
hypotension, with slowing heart rate, and sometimes fainting.
It occurs due to intense emotions of fear or panic. The autonomic
nervous system induces the release of hormones that slow the heart
rate and dilate blood vessels.
be due, for example, to Addison's disease.
disease leads to destruction of the adrenal glands, which can not
produce enough adrenal hormones (especially cortisol). Cortisol has
many functions; one among them is the maintenance of blood pressure
and heart function.
disease is characterized by weight loss, muscle weakness, fatigue,
hypotension, and sometimes darkening of the skin.
of a severe infection in which bacteria or other infectious organisms
enter the blood. The infection usually originates in the lungs (eg
pneumonia), bladder or abdomen due to diverticulitis or gallstones.
The bacteria enter the blood and release toxins produced there severe
hypotension (septic shock), often with damage to several organs.
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