Fainting can be a frightening experience—especially if you don’t know what’s caused it. In most cases, it’s something harmless. But when it’s not, fainting (known by medical professionals as “syncope”) can signal a life-threatening condition that requires appropriate and prompt medical care.

Because up to half of Americans will faint (that is, lose consciousness for no more than a few minutes and then return to their normal selves) at least once in their lifetimes, it’s crucial to get the right answer.

The problem: It has traditionally been difficult for doctors to differentiate between benign fainting that needs no treatment and potentially fatal fainting that requires close medical supervision.

Latest development: A tool that allows emergency department physicians to more accurately make that critical evaluation.

BENIGN FAINTING

An estimated 90% of people who go to a hospital emergency department after fainting do not have a serious condition that caused it.

The most common cause of this type of fainting is vasovagal syncope. When this occurs, the body overreacts to certain environmental conditions, which cause a person’s heart rate and blood pressure to drop suddenly.

Susceptible people can faint at the sight of blood or after having blood drawn…during an emotional shock or surprise…or when in a warm, crowded place. Once a person knows he/she has this condition, it’s just a matter of avoiding the situations that cause fainting.

You can also faint just from standing up if your blood pressure can’t adapt quickly enough—a condition called orthostatic hypotension. This health problem can be caused by dehydration…medications used for high blood pressure, such as beta-blockers and ACE inhibitors, or for enlarged prostate, such as tamsulosin (Flomax)…or nervous system damage due to diabetes or Parkinson’s disease. It’s important that orthostatic hypotension be identified and treated so that injuries from falls are prevented.

WHEN IT’S DANGEROUS

For the remaining 10% of fainters, the situation is more complicated.

About half of these episodes are due to an obvious cause, such as profuse bleeding…a measurable irregular heartbeat…bleeding in the brain (subarachnoid hemorrhage) or abdomen (ulcer)…a large clot in the lung…heart attack…or a tear in the wall of the main artery carrying blood out of the heart (aortic dissection)—all of which can lead to a sharp drop in blood pressure and result in not enough oxygen-rich blood getting to the brain. Most of these patients will be obviously sick when seen in the emergency department. These problems are dangerous and life-threatening, but can be treated once they’re detected.

It’s the final 5% of fainting episodes that are a physician’s nightmare. In these cases, patients can have similar conditions to those above, but they do not have symptoms and say they feel fine, which presents a diagnostic challenge.

This group also includes fainting episodes due to a silent heart condition present from birth (congenital) that can cause those afflicted to die at a very young age. These potentially fatal conditions include long QT syndrome, which is associated with abnormalities in the electrical system of the heart…and hypertrophic cardiomyopathy, in which the walls of the lower chambers of the heart (ventricles) are thickened. These and other heart conditions can lead to an erratic, fast heart rhythm, a precursor to cardiac arrest and death.

Physicians can detect these disorders simply, either in the hospital or office, with an electrocardiogram (ECG or EKG), which measures the electrical activity of the heart. But you can’t be diagnosed without an ECG, which is why prompt medical attention is so important.

A NEW WAY TO EVALUATE

This complex diagnostic maze is why researchers at The Ottawa Hospital and the University of Ottawa in Ontario, Canada, developed the Canadian Syncope Risk Score (CSRS), a new tool to help emergency department doctors focus on patients who are more likely to have serious underlying conditions that caused fainting.*

With this tool, doctors can rate a patient’s risk for potentially life-threatening conditions by applying factors such as whether the patient has a predisposition to vasovagal symptoms…history of heart disease…abnormal blood pressure readings during the emergency…unusual readings on the ECG…signs of heart attack in blood tests…and the presumed diagnosis of fainting  (vasovagal or cardiac).

WHAT TO DO IF YOU FAINT

Given the possibility of “nothing serious” or “possibility of death,” what should you do if you faint? When you see your doctor (emergency department and/or personal), you can mention the CSRS. In addition…

  • If this is your first fainting episode, and you also have a health danger sign—such as headache, chest pain or abdominal pain, or you fainted while exercising or exertion—call 911 and get to an emergency department immediately. Your fainting could be a red flag for a potentially fatal condition, such as heart attack or aortic dissection.
  • If this is your first fainting episode…you do not have other symptoms…and the episode was believed to be due to a fainting trigger (heat, emotional shock, etc.), you don’t have to go to the hospital, although you can for peace of mind. But see your primary care provider promptly for an evaluation and an ECG.
  • If you faint repeatedly, and the experience fits with a known pattern of vasovagal syncope (due, for example, to heat or emotional shock), there’s no need to see a doctor…provided you don’t have any of the danger signs listed above. It’s safe to assume these fainting episodes are benign. But you should avoid any triggers that have been identified.
  • If you faint frequently but have not been diagnosed with vasovagal syncope—or if you’re fainting more frequently—go to an emergency department to be evaluated and receive an ECG to identify conditions that can lead to life-threatening arrhythmias.

*To access the Canadian Syncope Risk Score, go to QxMD.com.