Epilepsy
Epilepsy is a condition that affects people of all ages, although younger children are more likely to have seizures than adults. Epilepsy occurs when there is abnormal electrical activity in the brain. Young children can have seizures if they have a high fever. This is called a febrile seizure and doesn’t mean a child has epilepsy.
What causes epilepsy?
In many cases there is no specific cause of epilepsy. A few known causes of epilepsy include genetics, minor brain injury or brain infection such as meningitis or encephalitis that produce scarring on the brain, abnormal development of the brain that may or may not be seen on MRIs, or brain tumours.
What are the symptoms of epilepsy?
Seizures can cause a wide variety of symptoms such as:
- Strange sensation on one side of the body
- Changes in behaviour or emotions
- Muscle spasms
- Convulsions
- Sudden loss of awareness or consciousness
There may be certain factors that contribute to seizures. Poor nutrition, missed medication, flickering lights, skipping meals, iIlness, fever, allergies, and lack of sleep are a few common triggers. Many people learn what their triggers are and strive to avoid them to prevent a seizure from occurring.
How is epilepsy diagnosed?
There are a variety of tests used to diagnose epilepsy. Electrical recordings of the activity of the brain called electroencephalograms (EEG), video-EEG telemetry, computed tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) can help doctors assess and visualize abnormalities.
- The above tests are described in tests/procedure section.
- A video-EEG is a test where a video camera is running simultaneously during an EEG, offering neurologists the ability to assess all aspects of the seizure.
Here are some terms that you may hear from your doctor with the diagnosis:
- Idiopathic means there is no apparent cause.
- Cryptogenic means there is a likely cause, but it has not been identified.
- Symptomatic means that a cause is known.
- Generalized means that the seizures are involving the whole brain at once.
- Focal or partial means that the seizure starts from one area of the brain.
Types of epilepsy
The two types of epilepsy are generalized and partial (focal). The seizures associated with generalized epilepsy (whole brain involved) are:
- Grand mal seizures: Patients lose consciousness and have muscle stiffness and convulsions. You will often hear this referred to as “tonic-clonic.” Tonic is referring to the stiffness and clonic is referring to the jerking motion.
- Petit mal or absent seizure: This type of seizure can occur multiple times in a day. There is a change in consciousness and patients may stare in a strange way.
- Clonic seizures: Patients experience jerking movement with no change in consciousness
- Tonic seizures: Muscles are stiff
- Atonic seizures: Muscles become weak
The types of seizure for partial (focal) epilepsy are:
- Simple: When people have simple partial seizures, they are fully awake, alert and able to interact during the seizure. These seizures are short in duration.
- Complex: During these seizures people can appear like they are day-dreaming and staring blankly. Some people will begin fidgetting or doing a repetitive movement such as picking at clothes or smacking their lips.
Managing seizures:
Some children have seizures that are controlled with medications while other children have seizures that are difficult to control, despite treatment. The type of epilepsy that is difficult to control is called medically intractable epilepsy. Uncontrolled epilepsy places the child at risk for physical injury during seizure/falls, adverse reaction to medications, learning impairments and disruption to daily life.
The first treatment option for epilepsy is always medication. There are many different types of medications that may be used depending on the type of epilepsy and frequency of seizures. If one medication is not successful in controlling the number and severity of seizures others may be added.
If a child is on multiple medications and continues to have debilitating seizures, a workup for brain surgery may be an option for your child. This workup will usually include continuous telemetry to try to determine the area of the brain that is causing the seizures. Patients may also require depth electrodes, a surgical procedure where, while your child is asleep, very thin electrodes are inserted into the brain to further identify the area where the seizures are starting. The electrodes are connected to a monitor for several days and continuous reading of the electrical impulses of the brain are recorded and analysed by your medical team to map the area of the brain that may need to be resected or removed. If an area of the brain is identified to be the primary spot of origin of the seizures then surgery may be an option.
It is important to remember that most children with epilepsy will have good control of their seizures with medications. There are even certain types of seizures that children may outgrow with time. Symptomatic seizures due to an area of scarring in the brain, abnormal brain development, or tumour are often more difficult to treat with medications alone. These are the ones where more investigations are necessary to determine if surgery can help stop or control the seizures. When a specific area of the brain is identified to cause seizures and we can see an abnormality on MRI, an operation to remove that abnormal area of brain can get rid of most seizures, and many children can even stop taking medications if they have had no seizures for a year.
Specific types of surgery include:
- Temporal lobectomy: Part of the temporal lobe of the brain (an area of the brain behind the eyes and just above and in front of the ears) can be scarred from early brain injuries or infections. This area of the brain is often the cause of symptomatic seizures. Removal of the scarred area of the temporal lobe is the most common operation done to control or eliminate seizures. This area of the brain is involved in memory. Temporal lobectomy needs testing by a neuropsychologist to determine how much risk there might be to memory after surgery. The type of memory loss can sometimes lead to difficulties in school, or may have minor impact on memory. It does not cause your child to forget who you are.
- Focal resection: When seizures are coming from an area of the brain that didn’t form properly, seizures are often difficult to control with medications. Removal of this part of the brain can be very successful in controlling seizures, depending on the size of the abnormal area. The normal functions of the brain have often moved away from this area and are not affected by surgery.
- Tumour resection: When seizures are caused by a brain tumour, removing the tumour can often stop the seizures.
- Corpus callosotomy: Children who have generalized seizures that are not coming from one part of the brain can sometimes have something called drop attacks. This is where the body loses all muscle control without any warning and children fall and can often have broken bones or other injuries. Sometimes the surgeons will cut the connection between the two sides of the brain (the corpus callosum) to stop the rapid spread of the seizure and prevent drop attacks. For these children, they will continue to have seizures and require medication, but hopefully the drop attacks stop and the children are at less risk of serious injury.
- Hemispherectomy: Children who have seizures coming from a large area of the brain, may have dozens of seizures every day that cannot be stopped with medications. For these children, we may consider a very aggressive operation to disconnect the side of the brain causing seizures. This operation causes weakness on the opposite side of the body, but children are still able to walk and even run with a limp.
Reference:
Epilepsy Health Center, webmd.com/epilepsy/guide/types-of-seizures-their-symptoms, reviewed January 23, 2014.
