ASK DR. BAUGHAN                                             April 21, 2000

FAINTING

“When is fainting a medical problem that needs attention?”

Fainting (swooning, passing out, and in the South, “falling out”) is a common phenomenon.  The medical term for fainting without a discrete medical problem is vasovagal syncope (sing-cope-ee).  It is fairly remarkable that it does not happen more often in us strange creatures who walk on two feet.  The nervous system (primarily the vagal nerve that controls many of our gut functions and the dilation and constriction of our blood vessels) and the vascular (“vaso-“) system must constantly be making adjustments to counter the effects of gravity as we change positions.  Imagine taking a fluid filled bag of skin with an internal framework of sticks (or bones) from a horizontal position to a vertical position.  All the fluid will want to settle toward the ground.  The same thing happens with our blood when we go from lying down to standing.  Our brains must rapidly and unconsciously send signals along the vagus nerve to our blood vessels in our legs and bodies telling them to tighten up so that blood will flow back up against gravity and still keep oxygen flowing to command central, our brains.  If it does not, the brain can’t work, it switches off, we faint, and unless we are strapped into a chair or held upright, we fall to the ground, then our circulatory system does not need to fight against gravity to get blood to our brains, and we wake up again.

If this only happens once or twice with position change, and if it is prevented by getting up slowly, then no medical treatment is necessary.  If it happens in reaction to a sudden stress (bad news, a scare, a needle stick or other pain), our bodies send signals to the blood vessels in our legs to dilate (GET READY TO RUN!!).  If we don’t run, though, it’s just like gravity stealing blood from our brains.  This also requires no medical attention.

If it happens repeatedly, though, several factors deserve review.  Is the person somewhat dehydrated?  Do they need to be drinking more fluids to keep the blood vessels adequately filled?  Are they taking medicine that interferes with the vasovagal response to position change?  Are they so fatigued that their vagus nerve can’t stimulate the vessels enough to keep fighting gravity?

If the above factors are not present, some other observations can be important.  Does the person truly lose consciousness temporarily?  If not, it may be a balance problem and not a vasovagal reaction.  Do they have any abnormal movements while unconscious to suggest a seizure?  Even with vasovagal syncope, a person may briefly have their eyes roll back and become rigid.  Only if there is more prolonged total body jerking motions would it be considered a seizure.  What is the heart rhythm and rate immediately after fainting?  If it is regular and between 60 and 100, that is normal.  If it is higher than 120 or lower than 60 or the beat is erratic, then a heart problem may be present.  If there is any chest pain or shortness of breath, then a cardiac evaluation may be in order.  Could it be a stroke?  If the person promptly wakes up, can speak coherently, move all arms and legs, and see normally, then probably not.  Do they have a history of a heart murmur?  Narrowing of the aortic valve of the heart can cause syncope and can usually be determined by listening with a stethoscope. 

We highly value our brains when they suddenly do not work right.  We ought to value them that highly when they are working.  The many ways we think of to tinker with our brains, such as alcohol and other drugs, are also common causes of fainting.  So protect your brain.  You’re not very interesting without it.