Fainting
(Syncope)
Definition:
Fainting is the sudden loss of consciousness.
Causes:
In general, fainting is caused by decreased blood flow to the brain.
This can occur due to:
- Vasovagal spells (most common cause) – simple fainting that can occur:
- During medical procedures
- During times of high stress, trauma, or fright
- After standing still for a long period of time
- Low blood pressure, especially when standing (called orthostatic hypotension)
- Dehydration
- Anemia due to blood loss
- Side effect of a medication
- Seizure
- Stroke or transient ischemic attack
- Too rapid or too slow heart rhythm
- Organic heart problems such as:
- hypertrophic cardiomyopathy
- pulmonary stenosis
- constrictive pericarditis
Risk Factors:
A risk factor is something that increases your chance of getting a disease or condition.
- Heart disease, especially congestive heart failure or abnormal rhythms
- Blood loss
- Medications, including:
- Blood pressure medications
- Drugs that enlarge blood vessels
- Antidepressants
- Drugs that regulate the heart's rhythm
- Water pills (diuretics)
Symptoms:
Symptoms include:
- Sudden loss of consciousness
- Inability to remain standing or sitting
- Consciousness regained without any need for intervention
- Dizziness or lightheadedness before losing consciousness
Diagnosis:
The doctor will ask about your symptoms and medical history, and perform a physical exam.
Tests may include (in order of importance):
Blood Tests – to look for anemia, hypoglycemia, low potassium, and low magnesium
Electrocardiogram (EKG) – a test that records the heart's activity by measuring electrical currents through the heart muscle
Holter Monitoring – a mobile EKG test that is performed over 24 hours, while you go about your usual daily activities
Head CT Scan – a type of x-ray that uses a computer to make pictures of the brain
MRI Scan of the Brain – a test that uses magnetic waves to make pictures of the brain
Echocardiogram – a test that uses high-frequency sound waves (ultrasound) to examine the size, shape, and motion of the heart
Cardiac Catheterization –a tube-like instrument inserted into the heart through a vein or artery (usually in the arm or leg) to detect problems with the heart and its blood supply
Electroencephalogram (EEG) – a test that records the brain's activity by measuring electrical currents through the brain
Treatment:
Treatment will depend on the underlying condition that has caused fainting. For example:
- Abnormal heart rhythms can be treated with medications or by implanting a pacemaker.
- If a medication is causing syncope, it may need to be changed or discontinued.
- Anemia or other blood abnormalities should be treated.
Prevention:
If you feel any warning signs, such as dizziness or lightheadedness, sit or lie down immediately so that you don't get hurt falling during a fainting spell.
If you are prone to fainting:
- Get up slowly and carefully from lying down. Start by sitting up. Don't ever jump to a standing position.
- Ask your doctor if you should be on a high-salt diet.
- Drink lots of fluids.
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