Seizure Diagnosis and Classification

The brain consists of nerve cells that communicate with each other through electrical activity. A seizure occurs when one or more parts of the brain has a burst of abnormal electrical signals that interrupt normal brain signals. Anything that interrupts the normal connections between nerve cells in the brain can cause a seizure. This includes a high fever, high or low blood sugar, alcohol or drug withdrawal or a brain concussion.

When is a seizure considered epilepsy?

Epilepsy, a brain condition that causes a person to have seizures, is diagnosed when a person has two or more seizures with no known cause. Epilepsy is the third most common neurological disorder in the U.S. and approximately 750,000 children have seizures or epilepsy. It affects children and adults of all races and ethnic backgrounds.

What are the different type of seizures?

There is a wide variety of seizures. The type of seizure depends on which part and how much of the brain is affected and what happens during the seizure. The two main categories of epileptic seizures are focal (partial) seizures, which affect only one side of the brain, and generalized seizures, which occur in both sides of the brain.

Focal (partial) seizures

Focal seizures are defined by abnormal electrical brain function in one or more areas of the brain that are confined to one side of the brain. Before a focal seizure, your child may have an aura, or signs that a seizure is about to occur, but this is more common with a complex focal seizure. Commonly auras involve feelings such as deja vu, impending doom, fear or euphoria. Your child may also experience visual changes, hearing abnormalities or changes in sense of smell.

The two types of focal seizures are:

  • Simple focal seizure. The symptoms depend on which area of the brain is affected. If the abnormal electrical brain function is in the part of the brain involved with vision (occipital lobe), your child’s sight may be altered. More often, muscles are affected. The seizure activity is limited to an isolated muscle group. For example, it may only include the fingers, or larger muscles in the arms and legs. Your child may also have sweating, nausea or become pale. Your child won’t lose consciousness in this type of seizure.
  • Complex focal seizure. This type of seizure often occurs in the area of the brain that controls emotion and memory function (temporal lobe). Your child will likely lose consciousness. This may or may not mean he or she will pass out. Your child may just stop being aware of what's going on around him or her. Your child may look awake, but have a variety of unusual behaviors, including gagging, lip smacking, running, screaming, crying or laughing. Your child may be tired or sleepy after the seizure. This is called the postictal period.

Generalized seizure

A generalized seizure occurs in both sides of the brain. Your child will lose consciousness and be tired after the seizure, which is referred to as the postictal state. Generalized seizures are categorized in several different ways including:

  • Absence seizure: This type of seizure is also called petit mal seizure. This seizure causes a brief changed state of consciousness and staring. Your child will likely maintain posture while his or her mouth or face may twitch or eyes may blink rapidly. The seizure usually lasts no more than 30 seconds, and when it is over, your child may not recall what just occurred. He or she may go on with activities as though nothing happened. These seizures may occur several times a day and are sometimes mistaken for a learning or behavioral problem. Absence seizures almost always start between ages 4 to 12.
  • Atonic seizure: This is also called a drop attack. With an atonic seizure, your child has a sudden loss of muscle tone and may fall from a standing position or suddenly drop his or her head. During the seizure, your child will be limp and unresponsive.
  • Generalized tonic-clonic seizure (GTC): Also called grand mal seizure, the classic form of this kind of seizure has distinct phases. Your child’s body, arms and legs will flex, extend and shake. This is followed by contraction and relaxation of the muscles (clonic period) and the postictal period. During the postictal period, your child may be sleepy. He or she may have problems with vision or speech, and may have a bad headache, fatigue or body aches. Not all of these phases occur in everyone with this type of seizure. 
  • Myoclonic seizure: This type of seizure causes quick movements or sudden jerking of a group of muscles. These seizures tend to occur in clusters. This means that they may occur several times a day, or for several days in a row.

What causes a seizure in a child?

In most cases, the cause of a seizure cannot be identified. In some, a seizure may be caused by one of or a combination of the following:

  • An imbalance of nerve-signaling brain chemicals (neurotransmitters)
  • Brain tumor or lesion
  • Stroke
  • Brain damage from illness or injury

What are the symptoms of a seizure in a child?

Your child’s symptoms will vary depending on the type of seizure they experience. General symptoms or warning signs of a seizure can include: 

  • Staring
  • Jerking movements of the arms and legs
  • Stiffening of the body
  • Loss of consciousness
  • Breathing problems or stopping breathing
  • Loss of bowel or bladder control
  • Falling suddenly for no apparent reason, especially when associated with loss of consciousness
  • Not responding to noise or words for brief periods
  • Appearing confused or in a haze
  • Nodding head rhythmically, when associated with loss of awareness or consciousness
  • Periods of rapid eye blinking and staring

During the seizure, your child’s lips may become tinted blue and his or her breathing may not be normal. After the seizure, your child may be sleepy or confused.

The symptoms of a seizure may sometimes mimic other health conditions. Make sure your child sees his or her health care provider for a diagnosis.

How are seizures diagnosed in a child?

Your health care provider will ask about your child’s symptoms and health history. You’ll be asked about other factors that may have caused your child’s seizure, such as:

  • Recent fever or infection
  • Head injury
  • Congenital health conditions
  • Preterm birth
  • Recent medicines

Your child may also have:

  • A neurological exam
  • Blood tests to check for problems in blood sugar and other factors
  • Imaging tests of the brain, such as an MRI or CT scan
  • Electroencephalogram (EEG), to test the electrical activity in your child’s brain
  • Lumbar puncture (spinal tap), to measure the pressure in the brain and spinal canal and test the cerebral spinal fluid for infection or other problems

How are seizures treated in a child?

The goal of treatment is to control, stop or reduce how often seizures occur. The most common type of treatment is medicine. Your child’s health care provider will need to identify the type of seizure your child is having. Appropriate medications are selected based on the type of seizure, age of the child, side effects, cost and ease of use. Medicines at home are usually taken by mouth as capsules, tablets, sprinkles or syrup. Some medicines can be given into the rectum or in the nose. If your child is in the hospital with seizures, medicine may be given by injection or intravenously by vein (IV).

It is important to give your child his or her prescribed medicines on time and as prescribed. The dose may need to be adjusted for the best seizure control. All medicines can have side effects. Talk with your child’s health care provider about possible side effects. If your child has side effects, talk to the health care provider, and do not stop giving medicine to your child. This can cause more or worse seizures.

While your child is taking medicine, he or she may need tests to see how well the medicine is working. You may have:

  • Blood tests: Your child may need blood tests often to check the level of medicine in his or her body. Based on this level, the health care provider may change the dose of medicine. Your child may also have blood tests to check the effects of the medicine on his or her other organs.
  • Urine tests: Your child’s urine may be tested to see how his or her body is reacting to the medicine.
  • Electroencephalogram (EEG): An EEG is a procedure that records the brain's electrical activity. This requires attaching electrodes to the scalp. This test is performed to see how medicine is helping the electrical problems in your child’s brain.

Your child may not need medicine for life. Some children are taken off medicine if they have had no seizures for one to two years. This will be determined by your child's health care provider.

Other treatments

If medicine does not help control your child’s seizures or your child has problems with side effects, your health care provider may advise other types of treatment. Your child may be treated with any of the below:

Ketogenic diet

A ketogenic diet is a type of diet that is very high in fat and very low in carbohydrates. Enough protein is included to help promote growth. The diet causes the body to make ketones. These are chemicals made from the breakdown of body fat. The brain and heart work normally with ketones as an energy source. This special diet must be strictly followed. Too many carbohydrates can stop ketosis. Researchers aren’t sure why the diet works, but some children become seizure free when put on the diet. The diet doesn’t work for every child.

Vagus nerve stimulation (VNS)

This treatment sends small pulses of energy to the brain from one of the vagus nerves – a pair of large nerves located in the neck. If your child is age 12 or older and has partial seizures that are not controlled well with medicine, VNS may be an option. VNS involves surgically placing a small battery into the chest wall. Small wires are then attached to the battery and placed under the skin and around one of the vagus nerves. The battery is then programmed to send energy impulses every few minutes to the brain. When your child feels a seizure coming on, he or she may activate the impulses by holding a small magnet over the battery. In many cases, this will help to stop the seizure. VNS can have side effects such as hoarse voice, pain in the throat or change in voice.


Surgery may be performed to remove the part of the brain where the seizures are occurring. Surgery helps to stop the spread of the bad electrical currents through the brain. It may be an option if your child’s seizures are hard to control and always start in one part of the brain that doesn’t affect speech, memory or vision. Surgery for epilepsy seizures is very complex and should be performed by a specialized surgical team. Although your child may be awake during the surgery, the brain itself does not feel pain. If your child is awake and able to follow commands, the surgeons are better able to check areas of his or her brain during the procedure. Surgery is not an option for everyone with seizures.

For certain types of epilepsy, minimally invasive surgery options are available. Texas Children’s Hospital is one of the leading centers in the world providing this type of operation. For more information, please visit the Minimally Invasive Epilepsy Surgery Center.

How can I help my child live with epilepsy?

You can help your child with epilepsy manage his or her health in the following ways:

  • If age-appropriate, make sure your child understands the type of seizure he or she has and the type of medicine that is needed.
  • Know the dose, time and side effects of all medicines. Give your child medicine exactly as directed.
  • Talk with your child's health care provider before giving your child other medications. Medicines for seizures can interact with many other medicines, causing them to not work well or cause side effects.
  • Help your child avoid anything that may trigger a seizure. Make sure your child gets enough sleep, as lack of sleep can trigger a seizure.
  • Make sure your child visits his or her health care provider regularly. Have your child tested as often as needed.

Keep in mind that your child may not need medicine for life. Talk with the health care provider if your child has had no seizures for one to two years.

If your child’s seizures are controlled well, you may not need many restrictions on activities. Make sure your child wears a helmet for sports such as skating, hockey and bike riding. Make sure your child has adult supervision while swimming.

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Additional Resources

To learn more about the Epilepsy Center at Texas Children’s Hospital and to inquire about admissions and patient candidates, please contact 832-822-0959.