Convulsive syncope is a type of fainting (temporary loss of consciousness) caused by a decrease in blood flow to the brain, which triggers involuntary muscle jerking or stiffening, often confused with a seizure.
Fainting
Fainting is a sudden and temporary loss of consciousness due to a brief decrease in blood flow to the brain. Fainting and syncope mean the same thing and are used interchangeably.
While fainting is common – up to 6% of the general population have had a faint – losing consciousness temporarily is very frightening. There can be many possible causes including trauma, pain, illness, heat, prolonged standing or crowded spaces. In many cases, a faint can be diagnosed from an eyewitness description. However, fainting can also be caused by a medical condition that affects the nervous system or the heart.
Symptoms
People who faint typically fall to the ground or slump in a chair and regain consciousness within seconds to a few minutes. A typical faint usually includes:
- Warning signs such as dizziness, visual changes or ringing in the ears may be experienced before fainting.
- A brief loss of consciousness, which may involve a fall.
- Spontaneous recovery within a few seconds or minutes.
Convulsive Syncope: when fainting may be confused with a seizure
Fainting can be mistaken for a seizure when the person has brief jerking, twitching, or convulsive movements during the episode. This can happen in over 10% of people who faint.
When jerks occur during a faint, it is called convulsive syncope.
Convulsive syncope can look very similar to a seizure, but:
- it is caused by reduced blood flow, not abnormal electrical activity
- it is usually easy to treat once the cause is identified
- it may happen again with future faints
- it is not linked to epilepsy
Different types of faints/syncope
Some different types of syncope include:
Convulsive syncope is when small jerking movements are seen after passing out with spontaneous and complete recovery. This occurs because of a decreased blood flow to the brain, causing seizure-like movements.
Vasovagal syncope is the most common type of faint. This happens when the heart beats too slowly and/or blood vessels expand, resulting in less blood flowing to your brain. Common triggers of vasovagal syncope include emotional stress, prolonged standing, having blood taken, severe pain, sneezing, coughing, etc.
Postural syncope (orthostatic hypotension) happens when there is a sudden drop in blood pressure after standing up. It can be caused by dehydration, illness, or medications taken for high blood pressure, depression, or psychiatric disorders.
Cardiac syncope this can result from abnormal heart rhythms or structural heart problems. This type requires urgent medical assessment.
Can you prevent or treat fainting?
Treatment options for syncope will depend on the specific cause. Once identified, a faint can usually be prevented.
If you feel like you are about to faint:
- Lie down with your legs raised, or sit and lower your head
- Use counter‑pressure manoeuvres such as hand gripping, leg movements, calf raises, tiptoeing, or marching in place
- Stay hydrated and avoid triggers such as heat or prolonged standing.
If you have had a faint or blackout, speak with your doctor to rule out other possible conditions.
Seizures vs convulsive syncope
Seizures and convulsive syncope are both neurological events that can look similar, but they have different causes.
- A seizure is a sudden, electrical disturbance in the brain, which can cause changes in behaviour, movements, feelings, and levels of consciousness.
- Convulsive syncope refers to a temporary loss of consciousness followed by jerky or convulsive movements, often caused by a temporary decrease in blood flow to the brain
