Fainting

Alternative names   

Passed out; Light-headedness - fainting; Syncopal episode; Syncope

Definition 

Fainting is a temporary loss of consciousness as a result of transiently decreased blood flow to the brain. Light-headedness is a vague feeling of dizziness or a feeling like a person is going to faint.

Considerations

Fainting (syncope) can be caused by any condition causing a reduction of circulating blood flow to the brain. The cause of fainting should be evaluated by a health care provider.

Fainting or syncope is characterized by sudden pallor, loss of consciousness, and occasionally slight twitching or convulsive movements. For a parent, seeing their child faint may be a terrifying experience.

A simple faint (vasovagal faint) is rarely preceded by pain, pressure, constriction in the chest, or shortness of breath. It can be preceded by weakness, giddiness, nausea, dizziness, and a sense that the surrounding noise is growing fainter and fainter.

Pathologic fainting or syncope may also be associated with heart conditions, most often abnormal heart rhythms (arrhythmias).

Common causes

Light-headedness can accompany mild illness such as the flu or the common cold, and may be a symptom of anxiety. Light-headedness without other symptoms is usually not serious.

Actual fainting can be caused by any condition restricting blood flow to the brain; this can be positional, physiological (an automatic body response to a stimulus), or a result of drugs or activity. The more common causes include:

• rigid standing at attention
• arising quickly from a prone position
• pressure on the neck (tight collar)
• abnormal heart rate or rhythm
• low blood pressure (hypotension)
• severe pain, injury or fright
• alcohol or drugs including anxiolytics, antihistamines, antihypertensives, vasodilators, decongestants, central nervous system depressants
• strenuous coughing, straining during a bowel movement or any other Valsalva maneuver (forced exhalation with closure of mouth and nose)
• hyperventilation

Home care

Follow your health care provider’s recommendations.

Susceptible individuals should avoid situations known to cause fainting. Avoid sudden changes in posture. A person who becomes light-headed when they stand up should generate vigorous muscle activity before standing, and stand slowly.

Immediate treatment for fainting includes:

• Keep the affected person lying flat or sitting forward with the head bent below the knees.
• Cool the room down or move the person to a cooler location if heat is a problem (This can be especially helpful for someone with a history of heart problems as a cause of fainting).

Call your health care provider if

• there has been a complete loss of consciousness, especially if it occurs after a head injury or if there is no readily identifiable cause (such as a susceptible individual who faints when they have blood drawn).
• fainting is accompanied by a feeling that the room is spinning (vertigo) or any other symptoms.
• fainting occurs in a susceptible person more often than rarely.
• this is the first time a person has ever fainted.
• medication or alcohol is suspected as the cause.
• lightheadedness lasts for longer than 3 weeks.

What to expect

The medical history will be obtained and a physical examination performed.

Medical history questions may include:

• quality
  • Does fainting occur with upright posture?
  • Does fainting occur with a change in body position?
• time pattern
  • When did the fainting occur?
  • Is this the first time the person has fainted?
  • Was this a single incident or did it occur more than once?
  • How long did the episode last?
• aggravating factors
  • Was there an apparent cause for the fainting?
  • If so, what was it?
  • Did it occur after exercise?
  • Did it occur after coughing?
• other
  • Did the person actually lose consciousness or black out?
  • Were any other symptoms present before or after the person fainted?

There will be a detailed examination of the heart, lungs, and nervous system. The blood pressure may be measured in various positions.

Diagnostic tests that may be performed include:

• ECG
• Holter monitor
• X-ray of the chest
• echocardiogram

If the fainting is determined to be a simple faint, no treatment is usually recommended except as noted in the home care section. Fainting in children often becomes less common as the person grows older.

After seeing your health care provider:
You may want to add a diagnosis related to fainting to your personal medical record.