What happens during a seizure?
Electrical activity in the brain is carefully balanced. Neurons (brain cells) fire singly or in small groups to accomplish a task (excitation) and then stop firing (inhibition). A seizure happens if many neurons fire at once in uncontrolled bursts. This firing interferes with how the brain normally functions:
- Neuron excitation and inhibition become unbalanced; either there is too much excitation, or too little inhibition.
- A small group of neurons begin to fire together.
- Other neurons nearby or throughout the brain also start firing together because of abnormal connections between neurons or groups of neurons — this firing is called hyper-synchrony.
- The neurons involved in the seizure send instructions to the parts of the body that they control which may result in movements, sounds or change in level of consciousness.
Provoked and unprovoked seizures
Seizures may be provoked or unprovoked.
- Provoked seizures are the direct, immediate result of a cause such as a head injury, infection, drugs, changes in concentration of electrolytes, such as salt or calcium, in the blood, low blood sugar or withdrawal from medication. Anybody can have a single seizure under these conditions. Provoked seizures are less likely to happen again and are not considered to be epilepsy.
- When a seizure is not provoked by an immediate cause such as the ones described above, it is called an unprovoked seizure. If a child has two or more unprovoked seizures, or a single unprovoked seizure and a high risk of further seizures, they are considered to have epilepsy.
Causes of epilepsy
There are many different causes of epilepsy. There are tests available to look for the cause. However, in 60–70% of cases, no apparent cause can be identified.
The cause of epilepsy can be classified into six categories:
- Structural: There is an abnormality in the brain tissue, including previous injury to the brain from trauma, car accident or stroke that makes the brain more likely to have seizures.
- Genetic: Some types of epilepsy run in families. In these cases, it is passed on from parent to child. Other times, a child has a new change in genes (mutation) that has only occurred in them and there is no family history. There are some types of epilepsy that have been linked to specific genes.
- Infectious diseases: Infections such as meningitis or encephalitis affect the brain and can cause seizures and epilepsy.
- Metabolic disease: The brain cells use energy in a way that makes them more likely to create abnormal electrical activity.
- Unknown: The cause of epilepsy is not yet known.
- Missing medication doses: This is the most common trigger.
- Lack of sleep: Children with epilepsy are encouraged to maintain a regular sleep pattern and avoid late nights. If your child has a medical condition that causes sleep loss, such as sleep apnea, treatment should be sought for this condition to decrease the risk of breakthrough seizures.
- Illness: Fever, vomiting and diarrhea can lower the seizure threshold.
- Alcohol and drugs: Too much alcohol or certain drugs (e.g., cocaine, ecstasy) can trigger seizures. Over-the-counter or herbal medicines may also trigger seizures. Always check with your medical team when starting your child on a new medication or supplement to determine whether it will affect their seizures.
- Hormones: For some women, changes in menstrual cycle can reduce seizure threshold. Their neurologist can propose changes to help with this trigger.
- Stress: Stress and anxiety, common in adolescents, are reported as seizure triggers. Participating in support groups can decrease stress and anxiety.
- Sensory input: Some children have triggers that include flashing lights, doing puzzles and soaking in hot water.
- Avoid triggers.
- Get enough sleep every night.
- Take prescribed medications regularly.
- Keep a medication reminder chart or other alerts to help with remembering to take medications.
Seizure threshold
The seizure threshold is not a specific measurement. It is a way of thinking about the balance between excitation and inhibition in the brain cells or neurons.
Sarah’s seizures are well controlled on anti-epileptic drugs. She has an important test tomorrow. She stays up three hours later than usual to study, and then takes her medication when she goes to bed. The next day, she has a seizure at breakfast.
Under normal circumstances, Sarah would not have had a seizure because her medication and her regular sleep schedule keep her seizure threshold high. The combination of taking her medication late and losing three hours of sleep lowered her seizure threshold just enough to trigger a seizure.
Some factors can lower the seizure threshold of a person with epilepsy.
While one of these things by itself might not be enough to cause a seizure, a combination of them may lower the seizure threshold enough to cause a seizure.
There are many things your child can do to help control seizures:
Many children do not have seizure triggers. Try to keep precise records and include details of what occurred before the seizure to identify a pattern and trigger. One way to do this is by keeping a seizure diary or using a seizure diary application on your phone or another device. Identifying common triggers and avoiding them can improve your child’s quality of life, as well as your own.
Reducing the risk of epilepsy
It is important to do everything possible to reduce seizures. If medication does not control seizures, children with epilepsy should be referred to an epilepsy specialist to determine if other treatments, such as a special diet or surgery, could help to control seizures.
Injury prevention
Children with epilepsy are more likely to have an injury. Make sure that your child takes reasonable safety precautions.
Drowning is about 10 times more common in people with epilepsy than those without epilepsy, so extra safety is required around water. Like all children, children with epilepsy should never swim or have baths alone. They are encouraged to have showers and keep the bathroom door open in case they have a seizure.
Injuries can also occur during a seizure. Like all children, those with epilepsy should wear a helmet when doing activities like bicycling, skateboarding, in-line skating or horseback riding.
Extra precautions need to be taken around fires and while cooking.
Make sure that babysitters, teachers and coaches know what to do if your child has a seizure.
SUDEP prevention
The best way to prevent SUDEP is to work with your doctor to prevent seizures, especially a type of seizure known as generalized tonic-clonic seizures. Taking medications as directed and identifying and avoiding seizure triggers are the best ways to reduce seizures. If your child has seizures at night or from sleep, it is important to be aware of any seizures that occur at night and check on your child during and following a seizure. Some families may choose to use a listening device (such as a baby monitor) to help adults in the home to be aware if the child has a seizure overnight.
Do seizures damage the brain?
A great deal of epilepsy research in humans and animals has focused on the question of whether seizures cause brain damage. Because there are so many different factors, including the specific epilepsy syndrome, other health conditions, the age of the child, the age at which epilepsy began, the treatment regimen and the child’s particular characteristics, this is a difficult question to answer.
It is not clear whether single seizures can cause brain damage or if it is the cumulative effect of many seizures that cause damage.
We know that:
- While children who have multiple seizures over a long period of time are at risk for long-term effects, children who have only one or a few brief seizures in their lives do not usually have long-term consequences.
- In animal studies, seizures lasting more than 30 minutes and frequent, recurrent seizures appear to cause some brain cell death and may affect learning and memory. We don’t yet know how these animal studies translate to children.
- If the child’s epilepsy is caused by underlying abnormalities of the brain, this abnormality may also cause learning and behaviour problems.
Most children with epilepsy do not have developmental disabilities. They have as wide of a range of cognitive abilities as other children, ranging from very intelligent to below average.
Can my child die from a seizure?
It is uncommon for a child to die from a seizure. However, people with epilepsy, particularly those who have other neurological disorders, do have a higher risk of death than people without epilepsy. The risks vary widely and depend on the individual child.
There is a higher risk of death if:
- The child has a significant underlying neurological disorder. For example, children with severe cerebral palsy may also have problems with swallowing. The difficulty swallowing makes it more likely for them to choke on food, fluids or secretions, and then develop pneumonia, an infection of the lungs. This can lead to complications with breathing that result in death.
- The child has status epilepticus, defined as a seizure lasting longer than 30 minutes; however, status epilepticus is less likely to cause death in children than in adults.
- The child is injured during a seizure, for instance through head injuries, drowning, burns or suffocation.
In the absence of these factors, the risks to the child are very low. Most of the time, death is related to the underlying cause of the epilepsy. If a child is otherwise in good health, their risk of death is small. Talk to your child's doctor about their specific situation.
SUDEP (Sudden Unexplained Death in Epilepsy)
SUDEP is defined as death for no obvious reason in a person with epilepsy. These deaths occur most often suddenly at nighttime. SUDEP does not always involve a recent seizure. In some cases, there is no evidence that a recent seizure has occurred.
SUDEP affects one in 1,000 people with epilepsy each year. The rates of SUDEP are about the same in adults and children; however, rates are higher in adults and children with seizures that are not well controlled by medication.
The most well-proven risk factors for SUDEP is frequent seizures, especially a type of seizure called generalized tonic-clonic seizures. Having even a few of these types of seizures each year increases SUDEP risk. SUDEP is also more common in people who have a neurological problem of which epilepsy is one of the symptoms and those with difficulty following their anti-seizure medication regimen (such as skipping doses).
More information about SUDEP and support for families who have been affected is available from SUDEP Aware and the SUDEP Institute.
Resources
Ontario Epilepsy Guidelines — Find recommendations to improve the quality and consistency of care for people living with epilepsy. These may be helpful in advocating for care for your child with epilepsy.