Syncope And Its Multiple Causes


Syncope is a medical term used for fainting, which is defined as a transient loss of consciousness caused when there is an insufficient flow of blood to the brain.

The severity of syncope can range from mild to life threatening as it may result from something as benign as dehydration, or in contrast, it can be a warning sign of some undiagnosed underlying serious condition.

Hypotension or low blood pressure is the primary cause of it. Blood pressure is the flow of blood or the pressure on the walls of arteries, Generally, heart pumps blood to all the parts of the body, including the brain. When the blood pressure becomes too low, the supply of oxygen rich blood to the parts of the body is affected. As a result, an insufficient supply of blood reaches the brain that causes syncope or fainting.

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Causes of syncope

There are many causes of syncope:

Over stimulation of normal reflex

Reflex mediated syncope is the most common cause of syncope and a large number of causes of syncope are associated with it. Syncope occurs as a result of overstimulation of normal reflex, which is associated with marked stimulation of the vagus nerve that slows the heart rate, lowers blood pressure, and decreases the flow of blood to the brain. Syncope can be categorized into  types:

  • Vasovagal Syncope - It is the most common type which is often provoked by emotional or physical stress, such as intense fear of something and standing for a long time. This type of fainting is preceded by some noticeable symptoms such as sweating, lightheadedness, problems with vision, and nausea.

  • Situational syncope - It is a type of syncope which usually occurs with certain types of actions such as while urinating or putting pressure.

  • Carotid sinus syncope - It results due to pressure on the carotid artery and it can occur due to various reasons such as wearing a tight fitted shirt.


Dysautonomia is a medical term used for the diseases which are caused due to any problem in the Autonomic Nervous System. In the body, the autonomic nervous system is responsible for controlling various essential functions such as heart rate, blood pressure, and dilation. Problems with autonomic nervous system impair the ability of the body to prevent the blood from pooling in lower extremities and gut, which causes a decrease in the blood pressure and triggers syncope.

Dysautonomia can occur due to various health problems such as Parkinson’s disease, rheumatoid arthritis, and diabetes. Millions of people across the world suffer from autonomic dysfunction. Autonomic dysfunction is diabetes patients, is known as diabetic autonomic neuropathy. It is considered to be a complication of diabetes which occurs when damage is caused to parasympathetic and/or sympathetic nerves in people having diabetes. The uncontrolled glucose level in the blood leads to damage to these nerves.  

Parkinson’s disease is another disease which is closely associated with syncope. Parkinson’s disease is a neurological disorder which occurs when there is a loss of the cells in the brain that are responsible for storing dopamine. Dopamine is an essential chemical required for controlling movement in the body. Parkinson’s disease is accompanied by the drop in systolic blood pressure, resulting in syncope.

Cardiovascular causes

Problems with the cardiovascular system is also associated with syncope. When there is an abnormality in heart rhythm, the heartbeat becomes irregular - too slow or too fast. Syncope can also occur when there is an abnormality in the structure of the heart, including the valves and arteries. Almost any heart problem can cause syncope, such as Arrhythmogenic right ventricular dysplasia and Subclavian steal syndrome.

Arrhythmogenic right ventricular dysplasia is a heart disease which is characterized by inflammation of both ventricles - right and left. It is a serious disorder which is associated with a significant decrease in health related quality of life. Apart from syncope, arrhythmogenic right ventricular dysplasia is accompanied by other symptoms as well such as palpitations.

Subclavian steal syndrome is a disease which is characterized by the symptoms of transient ischaemic symptoms and it occurs when there is a reversal of normal blood flow in the vertebral artery. Subclavian steal syndrome is associated with various symptoms and syncope is one of the common ones.

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