Syncope (Loss of Consciousness): A symptom, not a diagnosis..

Syncope, or fainting, is a form of sudden loss of consciousness caused by decreased or insufficient blood flow to the brain which can be of rapid onset, short duration, and spontaneous and complete recovery.  40% will experience syncope at least once in a lifetime. Syncope can occur when a normal reflex is overstimulated, which slows the heart rate and, along with dilation of blood vessels, lowers blood pressure and decreases blood flow to the brain.

Types of Syncope:

Vasovagal syncope is the most common type of fainting. It can be provoked by emotional or physical stress, for example, intense fear, prolonged standing in a crowded, warm room, or having blood drawn. It is often preceded by warning symptoms such as sweating, nausea, lightheadedness, and visual blurring.

Situational syncope occurs in relation to certain specific actions, most commonly urinating or straining with a bowel movement.

Carotid sinus syncope can occur with pressure on the carotid artery, often resulting from a tight-fitting shirt or shaving.

Orthostatic syncope Occurs immediately or up to 10 minutes after assuming upright posture from sleeping or sitting position. Orthostatic hypo-tension refers to low blood pressure that occurs while standing. This may result from dehydration, medications, or certain health conditions.

Cardiac Syncope(or cardiovascular) syncope is caused by arrhythmia and structural heart disease. These may occur in combination because structural disease renders the heart more vulnerable to abnormal electrical activity.

Disorders Mimicking Syncope

  • With loss of consciousness, i.e., seizure disorders, concussion
  • Without loss of consciousness, i.e., psychogenic “pseudo-syncope”



  • The history and physical examination are the most important tools in the initial evaluation of syncope.
  • Details of the syncopal event must be evaluated in detail, including postural, exertional, or situational symptoms, palpitations or cardiac symptoms, use of medications, family history of sudden cardiac death and personal history of cardiac disease.
  • Patients who experience syncope with urination, defecation, coughing, swallowing, or while drawing blood have situational syncope.
  • Syncope related to ischemia is presumed when symptoms are present with ECG findings.
  • Monitoring blood pressure during and after attack are necessary to know if it is related to change in the blood pressure
  • Syncope in patients with coronary artery disease requires evaluation for arrhythmia and ischemia. The evaluation includes exercise stress testing, myocardial perfusion imaging, or cardiac catheterization, depending on the patient’s level of risk and specific findings
  • EEG, Head CT, Head MRI are rarely used, may help in diagnosing seizure and neurological causes.
  • Sugar levels are also tested to rule out hypoglycemic attacks which can mimic syncope.



After knowing the type of syncope and the cause for it, management will be based on the type.

  1. Acute intervention includes physical maneuvers, eg: crossing legs or tugging arms, lowering head, lying down
  2. If it is orthostatic syncope, moving feet and leg few minutes before rising, rising slowly and step-wise will help.
  3. Syncope due to cardiac issues must be treated accordingly based on the test reports.
  4. Reduce / stop exacerbating medication.
  5. Long-term prevention includes education, diet, fluids, salt, minimizing caffeine/alcohol, support hose, sleeping with head of bed elevated, drug therapy,cardiac pacing.




Dr. Y. Alekhya

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