What is syncope

Syncope is the medical term for fainting which is sudden, temporary loss of consciousness (seconds to 3 minutes ) that usually related to temporary insufficient blood flow to the brain.

What causes syncope?

It may be caused by emotional stress, pain, pooling of blood in the legs due to sudden changes in body position, overheating, dehydration, heavy sweating or exhaustion.

Syncope also may occur during violent coughing spells (especially in men) because of rapid changes in blood pressure.

It also may result from several heart, neurologic, psychiatric, metabolic and lung disorders. It may also be a side effect of some medicines eg anti diabetic,social drugs ect.

What is neurally mediated syncope?

Neurally mediated syncope (NMS) is also called neurocardiogenic, vasovagal, vasodepressor or reflex mediated syncope. It’s a benign (and the most frequent) cause of fainting. NMS is more common in children and young adults, although it can occur at any age. NMS happens because blood pressure drops, reducing circulation to the brain and causing loss of consciousness. Typical NMS occurs while prolonged standing activities such as school assemblies  and is often preceded by a sensation of warmth, nausea, lightheadedness and visual “grayout.”

Some forms of syncope suggest a serious disorder which commonly related to heart problems are:

  • those occurring with exercise
  • those associated with palpitations or irregularities of the heart
  • those associated with family history of recurrent syncope or sudden death


A person may have some warning signs prior to syncope. He may have the feelings of dizziness or faintness which can be characterized by:

  • Quite sudden light-headedness
  • General weakness, then falling to the ground
  • Fading hearing or blurred vision
  • Nausea, hot and cold skin sensations
  • Paleness and sweating
  • Slow pulse
  • Rapid return of full consciousness

Usually the person invariably remembers the onset of the fainting spell. People who are prone to syncope they should lie or sit down when they become aware of the above symptoms.

However, it is important to check for heartbeat and breathing when a person faints. If the heartbeat or breathing is not present, this may be cardiac arrest rather than syncope.

Syncope is usually nothing to worry, but it can sometimes be a sign of serious problem. If you faint, it is important to see your health care provider and find out why it happened.

Syncope can happen to anyone and at any time, but there are certain conditions that increases the risk of syncope

  • Stress
  • Hot, humid weather
  • Stuffy, poorly ventilated rooms
  • Old age
  • Prolonged standing
  • Menstruation especially painful periods
  • Social drugs particularly alcohol
  • Medication especially anti blood pressure drugs
  • Diabetes


The majority of children and young adults with syncope have no structural heart disease or significant arrhythmia (abnormal heart rhythm). So, extensive medical work-up is rarely needed. A careful physical examination by a physician, including blood pressure and heart rate measured lying and standing, is generally the only evaluation required.

A common simple faint usually disappears in a few seconds or minutes with complete recovery. However, a person my acquire complications such as injury and concussion during falling.


  • If a person feels like fainting  they should sit down immediately and bend over with their head between their legs or lie down.
  • If the person faints and is breathing and has a normal pulse, leave them on the ground or floor with their head down and to one side and make them comfortable.  Elevating both legs helps return blood to the heart.

It is important to make sure the person has no underlying medical illness. Please seek medical advice as soon as possible  if medical problems cannot be rulled out or in cases with known underlying diseases.

For those who has no other problem, next steps can be followed:

  • Leave the person in the lying position for about 10 minutes.
  • ‘smelling salts’ (ammonium carbonate) can be carried and used in those prone to faint.
  • Resume normal activities as soon as possible.

Medication is not necessary for fainting but may be necessary for underlying heart disorders.

  • Electrocardiogram (ECG) is used to test for abnormal heart rhythms
  • Other tests, such as exercise stress test, Holter monitor, echocardiogram, etc. may be needed to rule out other cardiac causes of syncope.


  • If you are prone to frequent fainting spells, avoid activities in which fainting may endanger your life, such as climbing to high places, swimming, driving or operating dangerous machinery.
  • Avoid precipitating causes (e.g. prolonged standing in queues, hot weather)
  • Avoid sudden changes in physical activity.
  • Ensure your medication for any medical illness is taken regularly as prescribed by your doctors.


Vasovagal syncope (NMS) appears to have a good prognosis. Generally, recovery is usually complete within minutes to hours.

Persons with cardiac syncope are at increased risk for death from any cause of cardiovascular events


  1. John Murtagh’s Patient Education, Fifth edition, page 244.

  2. John Murtagh, General Practice, Third Edition, page 510.

  3. Incidence and Prognosis of Syncope, Elpidoforos S. Soteriades, M.D., Jane C. Evans, D.Sc., Martin G. Larson, Sc.D., Ming Hui Chen, M.D., Leway Chen, M.D., Emelia J. Benjamin, M.D., and Daniel Levy, M.D.N Engl J Med 2002; 347:878-885September 19, 2002

Last Reviewed : 31 May 2012
Content Writer : Dr. Norizzati Bukhary bt. Ismail Bukhary
Accreditor : Dr. Rosnah bte. Ramly