In physiology and medicine, hypotension refers to an abnormally low blood pressure. It is often associated with shock, though not necessarily indicative of it. Hypotension is not to be confused with hypertension.
Causes
Orthostatic hypotension or postural hypotension is a common cause of low blood pressure. It is caused by a change in body position, when a person moves to a more vertical position, an example of this is when someone moves from sitting to standing or from lying down to sitting/standing. Tilt-table testing can confirm this.
Reduced blood volume, called hypovolemia is the most common cause of hypotension. hypovolemia is often induced by excessive use of diuretics; relative hypovolemia is caused by vasodilator therapy with nitrate preparations and calcium channel blockers or with ACE inhibitors.
It has been recorded as a side-effect of certain forms of anesthesia, such as curare, in which event it is often treated by the anesthesiologist.
Another -- albeit rare -- form, is "Postprandial hypotension," which occurs 30-75 minutes after eating. It is not well understood.
Indicators
For most individuals, a healthy blood pressure lies between 90/50 mmHg to 135/90 mmHg. A small drop in blood pressure, even as little as 20 mmHg, can result in transient hypotension.
Symptoms
Low blood pressure is often accompanied by:
References
See also
The content of this page is retrieved from http://en.wikipedia.org/wiki/Hypotension under GFDL
