by Efrain Gonzalez MD

A handy guide

for physicians to share with their patients.

WHY do some people pass out at the sight of blood? Why do some faint for no apparent reason? After suffering a fall to unconsciousness, patients have questions such as: Why did it happen?  Is passing out a symptom of something serious? Patients are usually reassured to know that in many cases syncope is not serious—depending, of course, on the cause.

Syncope is a term that may be unfamiliar to many patients. It simply means a temporary loss of consciousness that results from an insufficient blood flow to the brain. Syncope affects about three percent of males and up to five percent of females at some point in their life.

There are many kinds of syncope, but three common types are as follows.

1. “Vasovagal syncope” is triggered by emotional stress, pain, trauma, or other disturbing event.

2. “Situational syncope” can occur during a coughing spell or while urinating or defecating.

3. “Carotid sinus syncope” can result when the carotid artery in the neck is constricted. Even a tight collar can contribute to passing out.

The type of syncope that patients are most familiar with is vasovagal syncope (also known as neutrally-mediated, reflex-mediated, neurocardiogenic, or vasodepressor syncope). This syncope is triggered by an emotional stressor—anything from an unpleasant sight (perhaps blood) to tragic news (perhaps the death of a family member). Vasovagal syncope can also be caused by heat exposure, standing for long periods, and having blood extracted during a lab test.

Those are just some of the triggers that can cause a malfunction in the nervous system, resulting in a sudden drop of heart rate and blood pressure. When the heart rate slows, blood pools in the legs, reducing blood flow to the brain. The sufferer may experience lightheadedness, dizziness, nausea, blurred vision, a feeling of warmth, and might also break out in a cold sweat. Shortly afterward, he or she passes out.

The remedy for this is usually keeping the patient on the ground for about 15 minutes in a cool and quiet place, if possible. If the patient cannot lie down, he or she should at least lower the head below the shoulders, perhaps between the knees.

This posture will increase blood flow to the brain and help the patient regain full consciousness. (That same posture can prevent a person from passing out when he or she feels lightheaded.) Usually the patient recovers after a short time and can resume normal activity.

What, though, if there is no identifying trigger to the fainting spell? In that case, syncope could be a sign of something more serious. For instance, sometimes fainting indicates a heart, metabolic, or lung disorder. And according to the National Institute of Neurological Disorders and Stroke (NINDS), while syncope isn’t normally a primary sign of a neurological disorder, “it may indicate an increased risk for neurological disorders such as Parkinson’s disease, postural orthostatic tachycardia syndrome (POTS), diabetic neuropathy, and other types of neuropathy.” Medications may also be behind episodes of syncope.  “Certain classes of drugs are also associated with increased risk of syncope, including diuretics, calcium antagonists, ACE inhibitors, nitrates, antipsychotics, antihistamines, levodopa, and alcohol,” notes NINDS.

Cardiac syncope results from a heart or blood vessel condition—for example, abnormal heart rhythm (arrhythmia). When this is the case, medical attention is crucial. A thorough checkup by a physician can help determine the underlying cause. Physicians use a number of tests. For example, a blood test can reveal whether the patient suffers
from anemia. An electrocardiogram, echocardiogram, and exercise stress test can also detect conditions such as an irregular heart rhythm or valve problems. A tilt-table test helps the medical technician monitor heart rhythm and blood pressure when the patient is put in various positions.

Most cases of syncope are benign and do not need treatment. Sometimes medication that is used to treat low blood pressure can help prevent future fainting episodes. There may be other approaches to help keep blood from pooling in the legs, including foot exercises and tensing the leg muscles while standing. As always, the goal of Heartwell physicians is to give each patient personalized care along with a thorough evaluation and diagnosis, followed by the most advanced available solutions.