Fainting spells

The sight of blood. A foul smell. An accident scene. An emotional upheaval. A hot day. The next thing you know, you feel woozy and you pass out. Sound familiar? Probably.

For fainting – or what doctors call syncope (pronounced sing-kuh-pee) – is extremely common. It is estimated that 30 to 50 percent of adults faint at least once. It also accounts for about three to five percent of all emergency room visits and six percent of all hospital admissions.

Syncope is a symptom, not a diagnosis. It comes on rapidly, usually the result of reduced blood flow to the brain. In most cases, recovery is prompt and little follow-up is needed. But loss of consciousness can also be a sign of something serious, so no episode of fainting should be taken lightly.

The Common Faint

The most common cause of fainting is vasovagal syncope, or the "common faint," sometimes also called neurally-mediated syncope. It’s usually not serious.

Vasovagal syncope occurs when the vagus nerve, which runs from the brain to the abdomen, is stimulated, resulting in an abnormal reflex that slows the heartbeat and widens arterioles (tiny arteries). Blood pressure falls, reducing blood flow to the brain (see diagram). Vasovagal syncope usually progresses from nausea and sweating to "whiting out" and loss of consciousness, followed by "coming to" on one’s own.

The cause can be fear, exhaustion, a distressing physical or emotional event, or even a stuffy room. Blood drawing or other medical procedures can touch it off. Some people faint only during certain activities, such as coughing, swallowing, blowing hard, or straining during urination or bowel movement. This situational syncope is a variant of vasovagal syncope.

Carotid sinus syncope occurs when pressure is applied to the carotid sinus. This small section of the main arteries supplying blood to the brain contains baroreceptors (pressure sensors). Stimulation of these sensors – from a tight collar or other pressures on the neck – causes a reflex slowing of the heart and expansion of the blood vessels. This combination produces a precipitous drop in blood pressure.

Other Causes Of Fainting

• Cardiogenic syncope. This type of fainting is usually related to abnormal heart rhythms and is more serious than vasovagal syncope. Fainting tends to occur suddenly and may be preceded by chest pain, shortness of breath, sweating, the sensation of pounding heart or a rapidly beating heart – all symptoms that suggest heart trouble. But sometimes, you faint without any warning at all. Cardiogenic syncope can occur if the heart beat goes too fast (tachycardia) or too slow (bradycardia). Fainting during exercise also may indicate problems with your heart.

• Medications. Drugs that affect blood pressure, cardiac output, or the brain may also cause syncope. These include tricyclic antidepressants, blood pressure-lowering agents, analgesics, sedatives, and vasodilators used for angina.

• Overuse of diuretics, vasodilators or angiotensin-convertimg enzyme (ACE) inhibitors. This may cause orthostatic syncope – fainting upon standing up due to a rapid drop in blood pressure. Standing suddenly after being in bedrest for a while may also result in orthostatic syncope.

• Seizures. Seizures share many characteristics with syncope, but they’re not the same as fainting. One way to tell whether your experience is syncope or a seizure is to recall your level of confusion after regaining consciousness. When syncope is to blame, post-event confusion usually lasts less than 30 seconds. After a seizure, however, it can last several minutes or considerably longer. Also, seizures may be accompanied by urinary or fecal incontinence and tongue biting.

Fainting First Aid

If you feel you’re about to faint, lie down immediately. If you can’t lie down, then sit down and bend forward with your head between your knees. This helps bring blood back to your head. Wait until you feel better before trying to stand up.

If you’re with someone who faints:

— Position the person on his back and elevate his legs above the heart level.

— Make sure the person has not vomited and is able to breathe.

— Place your ear over the person’s mouth and listen for the sound of breathing. If breathing stopped, call for immediate help or rush the patient to the nearest hospital. The problem is more serious than a fainting spell.

— If the person is breathing but doesn’t regain consciousness in one or two minutes, get medical help immediately.

— Loosen belts, collars, and any other restrictive clothing.

— If the person fell when fainting, treat any bumps, bruises or cuts as needed.

Treatment Strategies

How your fainting spells are treated depends on the cause. If your fainting is the common type (vasovagal) and your episodes are infrequent, you may need no treatment at all. That’s especially true if you have warning signs that you’re about to faint. In that case, you can take proper precautions to prevent a faint or to avoid injuries from falling as you lose consciousness.

When a specific cause is found, the treatment is specific and targeted to that cause. Here’s a sample of what you might expect.

• For frequent common faints. Avoid becoming dehydrated. Drink extra water, especially in hot weather. Rise slowly from a lying or sitting position to allow your body to adjust. Avoid activities that may trigger a faint if you can identify specific ones. Your doctor may prescribe a medication to prevent a fall in blood pressure. In rare cases, a pacemaker may be recommended.

• For situational syncope. Avoid situations that precipitate fainting, if possible. For example, lie down if you’re having blood drawn.

• For slow heart rhythm. A pacemaker may be inserted.

• For rapid heart rhythm. Treatment depends on the nature of the tachycardia. Your doctor may prescribe medications. You may have a procedure called ablation, in which abnormal electrical pathways in your heart are eliminated. Or you may have a defribillator implanted. This is a device resembling a pacemaker, but it can apply a controlled electric shock to your heart to stop a life-threatening tachycardia.

Making A Conscious Effort

Syncope can be caused by a number of conditions. Most are harmless, but some are potentially serious. If you experience fainting spells, see your doctor for an evaluation. With proper diagnosis and treatment, you may be able to diminish or prevent fainting spells or at least minimize the impact they have on your life.