Generalised seizures

Partial seizures
Nocturnal seizures
Status epilepticus
What are seizure triggers?
Does everyone get warning signs before a seizure?
What can I do if someone is having a seizure?

A seizure occurs when an abnormal electrical discharge occurs in the brain, disturbing its normal function. The type of seizure that results depends on where in the brain this takes place. There are two main categories of seizure; generalised seizures and partial seizures.

Generalised seizures
In this type of seizure, the whole brain is affected by abnormal electrical disturbances and the person loses consciousness. The following are examples of generalised seizures:


Tonic-clonic seizure

These can be considered the most dramatic type of seizure. Previously referred to as ‘grand mal’, they usually start with a cry and a loss of consciousness, with the person falling to the ground. A ‘tonic’ or stiff phase leads to a ‘clonic’ or twitching phase. This involves jerking of the arms and legs. The lips may turn blue and if the tongue has been bitten, blood may trickle from the mouth with frothy saliva. The person may become incontinent, however this does not always happen.

Tonic seizure
These seizures can also be considered quite dramatic. The muscles will stiffen and if the person is standing at the time, they will fall heavily to the floor. This can lead to injury. There is no jerking however.

Atonic seizure
The muscle tone is lost suddenly, causing the person to flop and fall. Sometimes referred to as ‘drop attacks’ or astatic seizures, these can also be quite dramatic. The person falls heavily to the floor, risking injury, particularly to the head and face. Recovery is swift however.

Clonic seizures
The muscles contract and relax continually causing repeated twitching and jerking.

Myoclonic seizure
During this type of seizure, the muscles jerk as if the person has had some sort of electric shock. These usually occur shortly after waking up or just before the person goes to bed when they are tired. There is a loss of consciousness but it is hardly noticeable because the period is so brief.

Absence seizures (typical)
These are relatively rare seizures and are usually confined to children. They occur suddenly and provoke a trance-like state. Affected children stare blankly into space and fail to respond to anyone talking to them. This can lead to problems in school as it may be assumed that they are simply not paying attention.

Absence seizures (atypical)
These seizures occur in people of all ages who have some form of brain damage. They last longer than simple absence seizures and result in major jerking or very sudden loss of muscle tone. Either of these can cause the person to fall heavily to the ground, risking injury.

Partial seizures
With this type of seizure, disturbances in brain activity begin in or involve a distinct part of the brain (as opposed to the whole brain in generalised seizures). The nature of the seizure is usually determined by the function of the part of the brain that is involved. Consciousness may be impaired. There are two main types; simple partial seizures and complex partial seizures.

Simple partial seizures
These are divided into two main categories – focal motor seizures and focal sensory seizures. There is no impairment of consciousness in either.

Focal motor seizures originate in the frontal lobes of the brain and cause movement of the limbs, head or neck. If the seizure is in the right frontal lobe, then the seizure movement is produced on the left hand side of the body and vice versa. Seizures originating in the frontal lobe can also involve an interruption in speech.

Focal sensory seizures originate in the parietal lobes of the brain, producing physical sensations such as tingling or unnatural warmth. If the seizure is in the right parietal lobe, it will produce a tingling or warmth on the left hand side of the body and vice versa.

Complex partial seizures
These seizures usually originate in the temporal lobes of the brain. They are non-convulsive in nature. They differ from simple partial seizures because they produce impaired or altered consciousness. This type of epilepsy is sometimes referred to as temporal lobe epilepsy or TLE.

The seizures often begin with a simple partial seizure, in which the person becomes disorientated but is still aware of what is going on. They may unknowingly pluck at clothing, smack their lips or wander about aimlessly. Their behaviour is seen to be out of character.

Secondary generalised seizures
It is possible for someone who has had a partial seizure to go straight into having a generalised seizure. In such a case, the generalised seizure is known as a secondary generalised seizure and it is usually atonic, tonic, clonic, or tonic-clonic.

Nocturnal seizures
Nocturnal seizures tend to occur either within the first few hours after going to sleep or 1-2 hours before the usual wakening time, particularly during lighter sleep. Since they occur while the person is asleep, they will often go unnoticed or unreported.

Features of nocturnal seizures include a witnessed focal or generalised tonic or clonic attack, waking with a bitten tongue or waking with a disordered bed.

If a person is known to have nocturnal seizures, the bedroom should be furnished appropriately, e.g. keep heavy furniture with sharp corners, such as bedside lockers, away from the bed, have a padded headboard and avoid the top bunks if bunk beds are used.

Status epilepticus
If a seizure is prolonged, or if there is a series of seizures over a period of time during which the person does not regain consciousness, this is referred to as status epilepticus.

This is a medical emergency requiring immediate treatment. When a seizure is prolonged, there is always a danger of a complication, such as brain damage caused by a lack of oxygen.

People with different types of epilepsy can develop status epilepticus. If a person with tonic clonic seizures develops it, this is known as convulsive status epilepticus – the most common type.

Only a small percentage of people with epilepsy will develop status epilepticus, however it is more common among young children. Treatment consists of the person being given diazepam as quickly as possible.

What are seizure triggers?
For most people with epilepsy, there is no single thing that triggers a seizure. However they can occur if the person gets very tired or hungry or forgets to take their medication.

Stress and alcohol can also bring on a seizure, but again this differs from person to person.

About 3-5% of people with epilepsy are photosensitive and may have seizures in response to flickering lights, such as strobe lights or a computer screen.

Does everyone get warning signs before a seizure?
Some people experience an unusual sensation, an odd smell or taste or a feeling of fear or sickness before they have a seizure. This ‘warning’ can last long enough for the person to move away from any potential danger or out of the public eye and lie down in a safe place.

This ‘warning’ is in fact the start of seizure activity in a part of the brain before it spreads to other parts. Sometimes this seizure activity does not spread and all that happens is an unusual sensation.

If the seizure is generalised and involves the whole of the brain from the beginning, there will be no warning.

What can I do if someone is having a seizure?
This depends on what kind of seizure a person is having. If they have an absence seizure, simply wait for it to pass and repeat anything they may have missed. If you are a parent or a teacher, you should keep a record of the occurrence and let the child’s doctor know about it.

If a person has a simple partial seizure and remains conscious, simply wait for it to pass. Reassure the person.

If the person has a complex partial seizure and is wandering around in a confused state, you may need to guide them away from any potential danger. Remember they may appear as though they are drunk or drugged. It is important to be gentle and reassuring.

If the person has a tonic-clonic seizure or a major convulsion, there are a few things you can do to protect them from injury:
Put something soft under their head to cushion it and prevent it from being damaged or cut
Remove anything they might injure themselves on, such as furniture
Help their breathing by turning them on the side and ensure they remain in this position until they come around

There is no need to move the person unless they have fallen in a dangerous place, such as at the top of stairs or against a hot radiator. Never put anything in their mouth as this may damage their teeth or jaw.

It is important that you remain calm and remember, seizures usually do not last beyond a few minutes. You only need to call an ambulance if:

  • The seizure lasts for longer than five minutes
  • The seizure lasts longer than is usual for the person involved
  • The seizure follows another seizure, without the person regaining consciousness in between
  • If the person has injured themselves.

Click here for more information about epilepsy:
www.epilepsy.ie

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