Alternative names   

Passed out; Lightheadedness - fainting; Syncope; Vasovagal

Definition   

Fainting is a temporary loss of consciousness due to a drop in blood flow to the brain. The episode is brief (lasting less than a couple of minutes) and is followed by rapid and complete recovery. You may feel lightheaded or dizzy before fainting.

A longer, deeper state of unconsciousness is often called a coma.

Considerations   

When you faint, you not only experience loss of consciousness, but also loss of muscle tone and paling of color in your face. You may also feel weak or nauseated just prior to fainting, and you may have the sense that surrounding noises are fading into the background.

Common Causes   

Fainting may occur while you are urinating, having a bowel movement (especially if straining), coughing strenuously, or when you have been standing in one place too long. Fainting can also be related to fear, severe pain, or emotional distress.

A sudden drop in blood pressure can cause you to faint. This may happen if you are bleeding or severely dehydrated. It can also happen if you stand up very suddenly from a lying position.

Certain medications may lead to fainting by causing a drop in your blood pressure or for another reason. Common drugs that contribute to fainting include those used for anxiety, high blood pressure, nasal congestion, and allergies.

Other reasons you may faint include hyperventilation, use of alcohol or drugs, or low blood sugar.

Less common but more serious reasons include heart disease (like abnormal heart rhythm or heart attack) and stroke.

Home Care   

If you have a history of fainting and have been evaluated medically, follow your doctor's instructions for how to prevent fainting episodes. For example, if you know the situations that cause you to faint, avoid or change them. Avoid sudden changes in posture. Get up from a lying or seated position slowly and gradually. When having blood drawn (if this makes you faint), tell the technician and make sure that you are lying down.

Immediate treatment for someone who has fainted includes:

• Checking the person's airway and breathing. If necessary, call 111 and begin rescue breathing and CPR.
• Loosening tight clothing around the neck.
• Keeping the affected person lying down for at least 10 - 15 minutes, preferably in a cool and quiet space. If the person cannot lie down, have him sit forward and lower his head below the levels of the shoulders, between the knees.
• If vomiting has occurred, turning the person onto one side to prevent choking
• Elevating the feet above the level of the heart (about 12 inches).

Contact your GP if you are concerned or if you have the above symptoms

Call 111 if:  

If the person who fainted:

• Fell from a height, especially if injured or bleeding.
• Does not regain consciousness quickly (within a couple of minutes).
• Is pregnant or over 50 years old.
• Has diabetes (check medical identification bracelets).
• Feels chest pain, pressure, or discomfort; pounding or irregular heartbeat; or has loss of speech, visual disturbances, or inability to move one or more limbs.
• Has convulsions, tongue trauma, or loss of bowel control.

Even if it's not an emergency situation, people should be evaluated by a doctor if they have never fainted before, if they are fainting frequently, or if they have new symptoms associated with fainting. Call for an appointment to be seen as soon as possible.

What to expect with your doctor:   

When you see your doctor, the focus of the questions will be to determine whether you simply fainted, or if something else happened (like a seizure), and to figure out the cause of the fainting episode.

The questions will include:

• How would you describe the dizziness that you felt before fainting? Did you feel light-headed, off-balance, or like the room was spinning?
• Was the faint associated with convulsions (jerking muscle movements), tongue trauma, or loss of control of your bowels?
• When you regained consciousness were you aware of your surroundings or were you confused?
• Did you experience chest pain or heart palpitations when you fainted?
• Is this the first time you fainted?
• When did you faint? What were you doing before it occurred? For example, were you going to the bathroom, coughing, or standing for a long time?
• Does fainting occur when you change positions -- for example, go from lying to standing?

The physical examination will focus on your heart, lungs, and nervous system. Your blood pressure may be measured in several different positions.

Tests that may be performed include:

• ECG
• Holter monitor
• X-ray of the chest
• Echocardiogram
• EEG

References   

American College of Emergency Physicians. Clinical policy: critical issues in the evaluation and management of patients presenting with syncope. Ann Emerg Med. 2001; 37(6): 771-776.

Marx J. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 5th ed. St. Louis, Mo: Mosby, Inc.; 2002.

Ganzeboom KS. Prevalence and triggers of syncope in medical students. Am J Cardiol. 2003; 91(8): 1006-1008, A8.

Update Date: 6/3/2005