Syncope accounts for almost 40 percent patients visiting a clinic for the complaints of ‘sudden fall episodes’. It is a transient loss of consciousness associated with the loss of body tone. Most of the patients recover spontaneously. It may occur as a single event without any specific causation or can also be recurrent when it is associated with some organic pathology. The basic pathophysiology includes reduced cerebral blood flow.
An occurrence of syncope needs to be differentiated from a seizure episode, since it mimics the later very closely. A recurrent an d unexplained episodes of syncope need to be examined for possible structural cardiac pathologies, since it can lead to death if not attended in time. Most of the times, syncope occurs suddenly without any warning, but few patients can experience pre-syncope manifestations like light-headedness, dizziness, a feeling of warmth, nausea, and visual blurring.
The transient reduction in the cerebral blood flow is mostly due to three basic causes
1. Disturbance in the vascular tone or blood volume
2. Obstructive cardiovascular disorders and rhythm abnormalities
3. Cerebrovascular diseases
The disturbance of vascular tone or blood volume can be due to situations like cough, micturition, defecation or valsalva maneuver as well as due to carotid sinus hypersensitivity. Also due to orthostatic hypotension because of some vasodilator drugs, pure autonomic failure, peripheral neuropathy, and decreased blood volume. Cardiac rhythm abnormalities like sinus bradicardia, sinus arrest, atrioventricular block or atril flutter and fibrillation can also lead to syncope. Vetebrobasilar insufficiency or basilar artery migraine are one of the cerebrovascular diseases causing syncope.
Disorders that can mimic syncope are few metabolic disorders like hypoxia, hypoglycemia, anemia or hyperventilation or some psychogenic events due to anxiety attacks or hysterical fainting.
Neurocardiogenic or vasovagal syncope is usually associated with both sympathetic withdrawal [vasodilatation] and increased parasympathetic activity causing bradicardia. These are precipitated by alcohol consumption, severe pain, extreme fatigue, hunger, prolonged standing, exposure to hot or crowded environment, and during emotional situation.
The above mentioned pathologies should be ruled out by conducting diagnostic tests after a thorough clinical history – including serum electrolytes, glucose and blood counts. Electrocardiogram, cardiac enzymes need to be checked in case of cardiac causes. An electroencephalogram will rule out the possibility of a seizure activity.
Sporadically occurring syncope attacks do not need any treatment if you diagnose them of vasovagal origin. Remedies like gelsemium, belladonna, conium and phosphorus have been most effective in treating intermittent episodes of syncope.