Low Blood Pressure
Alternate Names : Hypotension
Low blood pressure is a term for blood pressure that is abnormally or dangerously low.
What is going on in the body?
Blood pressure is given as two numbers (140/90, for example) that describe the amount of pressure inside the arteries of the body. Arteries are blood vessels that carry blood from the heart to the rest of the body. Blood pressure is fairly easy to measure. The pressure is related to blood flow inside the arteries, much like the pressure inside a hose is related to water flowing through it. Many conditions can cause low blood pressure.
What are the causes and risks of the condition?
There are many possible causes of this condition, including:
medications, such as those used to treat high blood pressure. In this case, the medication may work too well and make the blood pressure too low. Many other medications, such as the sedative diazepam or amitriptyline, which is used to treat depression, can cause low blood pressure in some people.
heart conditions, such as abnormal heartbeats called arrhythmias or congestive heart failure. Cardiac tamponade, a condition in which fluid builds up around the heart and prevents it from pumping well, is another possible cause.
excessive blood loss
dehydration, which may be due to vomiting, diarrhea, or not getting enough fluids
a very serious blood infection known as sepsis
hypothermia, or an abnormally low body temperature
severe allergic reactions of any kind, often called anaphylaxis
low levels of oxygen in the blood, called hypoxia, which may be due to severe asthma, pneumonia, or other conditions
a hormone imbalance known as adrenal insufficiency, which can be caused by Addison's disease
high levels of acid in the blood, such as respiratory acidosis or metabolic acidosis
nervous system conditions. One example is diabetic neuropathy, or nerve damage caused by high glucose levels when diabetes is not well controlled. Serious head injuries or other nervous system damage may also cause low blood pressure.
Other causes are also possible. In some cases, no cause can be found. Some people always have a blood pressure that is low compared to other people, but normal for them. They may not have any symptoms from their low blood pressure because it is normal for them.