Types of Syncope or Fainting

Syncopes are characterized by a loss of consciousness that are usually accompanied by cold skin, pallor and shallow breathing. We'll explain why it occurs and the main types.
Types of Syncope or Fainting

Last update: 06 May, 2021

Syncope or fainting is a very frequent situation. It’s a temporary loss of consciousness, and is due to a decrease in blood flow to the brain.

Many people use the term fainting instead of syncope. The fact that there may be a decrease in cerebral blood flow may be due to multiple reasons. For this reason, different types are distinguished according to their etiology.

General symptoms of syncope or fainting

Syncope is defined as the transient loss of consciousness and postural tone. According to a study published in Frontiers in Physiology, it’s a very frequent problem. So much so that specialists estimate its incidence at between 15 and 39% of the general population.

Moreover, it can affect people of any age and sex. However, it’s true that its incidence increases with age. From the age of 70 upwards, this problem becomes more common.

Fainting is usually accompanied by a number of very characteristic symptoms. As stated in the MSD Manual, presyncope is characterized by the perception of dizziness and impending fainting. However, actual loss of consciousness still hasn’t occurred.

A person suffering from syncope actually loses consciousness. Their skin is usually cold and clammy. Their pulse weakens and breathing becomes very shallow. Just before losing consciousness there’s usually lightheadedness, blurred vision, a headache, and weakness.

In some cases, involuntary muscle movements may appear. They can seem to be convulsions, but they aren’t. This is one of the most relevant differential diagnoses that doctors must make.

What types of syncope are there?

Earlier, we noted that syncope is due to a decrease in blood flow to the brain. This, in turn, can have multiple causes. For this reason, specialists have identified different types, which we’ll explain in the following sections.

A fainted man.
Syncope has different types of presentation. Presyncope may precede the actual syncope.

Neuromediated syncope

This type is also known as reflex syncope. It’s the most frequent. What happens is that certain reflexes of the autonomic nervous system, which are responsible for maintaining blood pressure and heart rate, are deregulated.

As a result, the heart slows down and blood pressure decreases. This results in less blood flow to the brain.

The vasovagal variant, as explained by Mayo Clinic specialists, is that which occurs when the body reacts disproportionately to certain triggers. For example, to pain or strong emotions.

On the other hand, there’s fainting related to the carotid sinus. It appears when pressure is exerted on the carotid artery, which is located in the neck. It’s frequent in some men while shaving or when wearing very tight ties.

Lastly, neuromediated syncope can also be situational, when performing specific actions or movements. It most commonly occurs when coughing or laughing.

Fainting of cardiac origin

Cardiac or cardiogenic syncope, as its name suggests, is due to a problem in the heart. The most frequent cause is arrhythmias, such as tachycardias.

There may also be a structural problem, such as valvular disorders or ischemic cardiomyopathy. These people often experience palpitations and chest pain.

Orthostatic syncope

Orthostatic syncope is syncope that occurs when a person stands up. According to a study published in Offarm, the cause is that this movement causes a sudden drop in blood pressure.

Sometimes there’s a link with certain medications taken. For example, with antidepressants. It may also be associated with alcohol consumption, dehydration and blood loss.

Cerebrovascular syncope

Cerebrovascular syncope is related to a problem in the blood vessels responsible for administering oxygenated blood to the brain. It’s one of the least frequent and the most serious.

For example, it may be due to the presence of aneurysms or be the result of a stroke. In most cases, the cause derives from a problem of atherosclerosis that reduces the caliber of the arteries and prevents blood from flowing normally.

You may be interested in: Causes of Chest Pain When Breathing

How to deal with the different types of syncope

Earlier we saw that syncope was characterized by a series of symptoms and that some of them act as a warning of what’s going to happen. It’s important to know how to act in order to prevent possible complications related to falls or blows when losing consciousness.

In the event of syncope

When the sensation of weakness or imminent fainting appears, it’s essential to find a place to sit or lie down, ideally lying down with the legs raised to help the blood to descend with the impulse of gravity towards the brain.

This also reduces the risk of falling if fainting finally occurs. When you lose postural tone and fall, you could hit your head against any object or the floor itself.

It’s important to remain lying down or sitting until the feeling of dizziness disappears. Similarly, when it’s time to get up, get up slowly and gradually.

Helping others

If you see someone who feels dizzy or is fainting, try to help them. The first thing to do is to check if the person has collapsed and if they’re breathing. It’s important to remember that lung dynamics are usually weaker and shallower, but should be felt.

In any case, it’s also essential to ask for help. Especially if the person doesn’t regain consciousness or has any injury.

A fainted woman in a park
Helping someone suffering from syncope requires speed and having an emergency contact at hand.

How can doctors make the differential diagnosis?

The fact that there are so many reasons why syncope or fainting can occur means that it’s sometimes difficult to make a differential diagnosis. Although it’s true that the vast majority of cases are benign and transitory, when it happens very frequently it’s essential to find the reason.

For this reason, the physician must know the patient’s complete medical history. Especially if they suffer from any type of disease or if they’re taking any medication. In addition, it’s important to perform a correct examination.

The most commonly used complementary tests are the electrocardiogram and the echocardiogram. The former allows us to observe the electrical activity of the heart. It’s a simple, innocuous and low-cost test. The electrocardiogram, on the other hand, provides a detailed image of cardiac morphology.

Doctors can also prescribe a stress test. Carotid sinus massage consists of massaging the carotid artery to check whether syncope occurs. The doctor can complement it with magnetic resonance imaging or computed tomography.

Some syncope or fainting can be prevented

Syncope often occurs in response to certain triggers that can be easily identified. For example, they usually appear when there are low blood sugar levels or dehydration.

Therefore, a simple way to avoid fainting is to eat several times a day, even if it’s in smaller quantities. Similarly, drink enough water. Avoiding alcohol and other drugs, such as marijuana, also reduces the risk.

Whenever you have to get up, specialists recommend that you do it slowly and progressively. Even more so if you’ve been lying down for a long time. However, if you faint frequently, you should visit your doctor.

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Vasovagal Syncope: Symptoms, Causes, and Treatment

Vasovagal syncope is a short-lived malaise which manifests as a loss of consciousness for a brief period. It's happened to most adults.