What is hypotension?

Causes and Symptoms

The body has a complex system for regulating blood pressure, which ensures adequate blood flow to each organ and tissue. The sympathetic and parasympathetic branches of the autonomic nervous system, various hormones produced by the adrenal and pituitary glands, the kidneys, the heart, and local mechanisms in all parts of the body control the amount of blood in the vessels, how much blood is squeezed out of the heart with each beat, and how much blood is available to any body system at a given time. A failure in any of these regulatory areas can cause the blood pressure to become too low for the person to function normally.

Normal blood pressure varies depending on the demands put on the body, how fit a person is, and the age of the individual. For most adults, 120/80 is considered normal; however, the top number (systolic pressure) can be as low as 90 and the bottom number (diastolic) as low as 60 and still be considered normal. When the blood pressure is lower than about 90/60 and the individual develops symptoms related to the low pressure, then that individual is diagnosed with hypotension. Low blood pressure by itself is not unhealthy, especially in athletic people, but when the flow of blood to the organs of the body is inadequate, symptoms develop. They include rapid heartbeat, light-headedness or dizziness, weakness, and possibly fainting. Other symptoms vary with the cause of the low blood pressure.

Low blood pressure associated with insufficient blood flow to the body organs can cause kidney failure, strokes, and heart attacks. Orthostatic hypotension is low blood pressure and its associated symptoms that are most pronounced when a person goes from lying or sitting to standing.

Specific causes of hypotension include adverse drug reactions, diseases such as diabetes that damage the autonomic nervous system, hormone-producing tumors, fever, heart disease, dehydration, hemorrhage, excessive heat, alcohol use, heart attack, heart trauma, abnormal heart rhythms, overwhelming infection, anaphylaxis, burns, vomiting, and diarrhea.

Treatment and Therapy

The treatment of hypotension is primarily aimed at removing the underlying cause—for example, discontinuing a drug that causes blood vessels to dilate or wearing elastic stockings to improve blood flow back to the heart. If the low blood pressure is severe enough, then supportive treatment with fluids, oxygen, and other modalities may be required.

Bibliography

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Voyatzis, Diane. "Orthostatic Hypotension." Health Library, 25 Mar. 2013. Web.