Diabetic Fainting: Two Types of Syncope

Fainting, also called syncope, results from a temporary insufficiency in the supply of blood to the brain. Syncope can be the result of many disorders, some benign and some more serious. Some of the complications of diabetes can lead to episodes of syncope.

Two Types of Syncope

There are two primary body systems that are responsible for fainting. The first is the autonomic nervous system - the brain, nerves and spinal cord. These are the areas of the body that automatically regulate such functions as heartbeat, breathing and blood pressure. The second is the cardiovascular system.

Autonomic Nervous System Syncope

This type of syncope is also known as neurally mediated syncope, and it is the most common cause for fainting. It results from a failure of the autonomic nervous system to maintain blood pressure at an appropriate level. This may be due to a momentary slowing or pause of the heart (vasovagal syncope) or, conversely, an abnormal speeding of the heart rate upon standing (postural orthostatic tachycardia).

The triggers can also be as simple as seeing something unpleasant (think of the person who faints at the sight of blood or a needle), sudden heat or sudden pain.

Coughing or sneezing, or even laughing can also cause a fainting spell. This is called situational syncope.

Blood sugar levels also have an impact. If blood glucose is not well controlled, it can damage nerve fibers. This damage can happen to the nerves that control blood pressure, resulting in ineffective control of blood pressure, increasing the incidence of fainting.

Cardiovascular Syncope

Orthostatic Hypotension is another cause of fainting. This one is most common in those over 65 years of age and results from a drop in blood pressure upon standing.

Standing up causes blood to pool in the legs, as the result of gravity. The nervous system is supposed to respond by increasing the heart rate and narrowing the blood vessels, keeping blood circulation steady. If this doesn’t happen, the patient could faint.

One of the causes of orthostatic hypotension is diabetes. If diabetes is not well controlled, urination can be frequent, leading to dehydration. A lower fluid volume in the blood reduces blood pressure, which increases the risk of fainting.

Source: UK National Health Service
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