Fainting (cont.)
Orthostatic hypotension
Blood vessels need to maintain their tone so that the body can withstand the
effects of gravity with changes in position. When the body position changes from
lying down to standing, the autonomic nervous system
(the part of the brain not under conscious control), increases tone in the blood
vessel walls, making them constrict, and at the same time increases the heart
rate so that blood can be pumped upward to the brain. As people age, blood vessels may become less
resilient, and orthostatic hypotension (relative low blood pressure with
standing) may occur and cause syncope.
Vertebrobasilar system
Blood vessels to the brain are no different than any other blood vessels in
the body and are at risk for narrowing with age,
smoking, high blood pressure,
high cholesterol, and diabetes. While most people are aware of the carotid
arteries that supply the thinking parts of the brain, another set of arteries
supply the base of the brain. This vertebrobasilar system is also at risk for
narrowing, and should there be a temporary disruption in the blood flow to the
midbrain and the reticular activating system, fainting or syncope may occur.
Electrolyte imbalance
Electrolyte and hormone abnormalities may also be responsible for syncope;
however these causes are due to their effects on the heart and blood vessels.
Other medications and drugs
Other medications or drugs may also be potential causes of fainting or syncope including those for
high blood pressure that can dilate blood vessels, antidepressants that can
affect heart electrical activity, and those that affect mental status like pain
medications, alcohol, and cocaine.
Next: Pregnancy »
- Beta Blockers - Learn more about Beta Blockers, a drug that treats angina and other heart rhythm disorders, migraines, high blood pressure, panic attacks, and tremors. Generic and brand names are included in the article.
- Complete Blood Count (CBC) - A complete blood count (CBC) measures the concentration of white blood cells, red blood cells, and platelets in the blood and aids in the diagnosis of conditions and diseases such as anemia, malignancies, and immune disorders.
- Low Blood Pressure - Learn about low blood pressure (hypotension). Low blood pressure is blood pressure below normal and symptoms may include: lightheadedness, dizziness, fainting upon standing (orthostatic hypotension). There are many causes of low blood pressure, and treatment is dependant upon the cause.
Latest Medical News
Neurology RSS