Seizures

SEIZURES

According to the International League Against Epilepsy classification of 2017, seizures are generally described in three major groups, depending on where they start: focal onset, generalized onset and unknown onset.

LEARN

Seizures have an impact on brain functions.

There are several millions of nerve cells in our brain that are responsible for passing electrical signals between each other and that all together contribute for the correct functioning of the brain. The interruption or overload of these signals can lead to seizures, and these have a consequent impact on the brain functions, like mood, memory, movement, among others.

What happens to you during a seizure depends on what part of your brain is affected.

There are many different types of seizures. What happens to you during a seizure depends on what part of your brain is affected. With some types of seizures you remain alert and aware of what’s going on around you, and with other types you lose awareness. You may have unusual sensations, feelings or movements. Or you may go stiff, fall to the floor and jerk.

It is important to note the distinction between seizures and epilepsy. A seizure is an event and can be a symptom of other medical problems. Some seizures are caused by conditions such as low blood sugar (hypoglycaemia) or a change to the way the heart is functioning or even a high temperature that can occur in young children, known as febrile convulsions.

To understand epileptic seizures and its classification, it`s useful to know that the brain is divided into two halves, called hemispheres. Each hemisphere of the brain has four parts, called lobes, and each lobe is responsible for different functions.

Seizures are generally described in three major groups.

Epileptic seizures can start in one hemisphere (focal onset) or affect both hemispheres from the start (generalized seizure). Where a seizure starts is known as the seizure onset.

EPILEPSY SEIZURES

01_

FOCAL ONSET SEIZURE

The term focal is used instead of partial to be more accurate when talking about where seizures begin and about 60% of people with epilepsy have focal seizures. Focal seizures originate within a neuronal network limited to one hemisphere that might affect a large part of one hemisphere or just a small area in one of the lobes. What happens during a focal seizure depends on which area (lobe) of the brain is affected, and whether the seizure spreads to affect other areas. Some focal seizures involve movements, called motor symptoms, and some involve unusual feelings or sensations called non-motor symptoms.

02_

GENERALIZED ONSET SEIZURE

Seizures that start simultaneously in both hemispheres of the brain. They affect the entire brain and cause in the majority of the cases loss of consciousness. This episode can last from a few seconds to some minutes and there will be no reminder of what happened. Similar to focal seizures, these seizures can be classified according to motor or nonmotor manifestations.

03_

UNKNOWN ONSET SEIZURE

When the beginning of a seizure is not known, it’s now called an unknown onset seizure. A seizure could also be called as unknown onset if it’s not witnessed or seen by anyone, for example when seizures happen at night or in a person who lives alone.
As more information is learned, an unknown onset seizure may later be diagnosed as a focal or generalized seizure.

Not all seizures can be easily defined as either focal or generalized. Some people have seizures that begin as focal seizures but then spread to the entire brain. This is called a focal to bilateral tonic-clonic seizure (previously called a secondarily generalised tonic clonic seizure). Seizures can be different from one person to the other and to have epilepsy doesn’t mean to know what type of seizures each one has.

What happens after a seizure varies from person to person, some people recover immediately after a seizure, while others may take minutes to hours to feel as they did before the seizure. During this time, they may feel tired, sleepy, weak, or confused.

Triggers of Epileptic Crisis
Be aware!

FACTORS THAT MAY TRIGGER A CRISIS

There are things that can trigger a seizure in a person with epilepsy. In other words, certain triggers may cause an epileptic seizure. They are not the cause of the crisis itself, but they make it more likely that a seizure will occur. Not everyone has these “triggers” of epileptic crises and a factor that may trigger a crisis in one person may not affect others in the same way. However, it is useful to be aware of some factors that are usually described by people with epilepsy as triggering epileptic seizures:

(Taking the medication for epilepsy regularly and according to the doctor’s instructions is essential to maintain a stable level of the medicine in the blood. There are several studies showing that missing a dose of the medicine for epilepsy increases the risk of developing an epileptic seizure);

(3 in every 100 persons with epilepsy have seizures triggered by flashing lights or lights with bright patterns. This phenomenon is called photosensitive epilepsy);

(some women with epilepsy have greater susceptibility to seizures during certain periods of the menstrual cycle);

(some people say they are more prone to seizures when they are ill with infections that cause high fever).

It is good to remember that each case is unique and people with epilepsy do not react all in the same way nor are seizures triggered by the same factors.