Convulsion In Children Usually Won’t Cause Brain Damage
Question: Our four-year-old daughter has had many convulsions since she was a few months of age. Our paediatrician and neurologist have tried her on several medications. None of them work very well. She continues to have convulsions from time to time. These were mostly very brief, but a few of them were rather long. Sometimes we had to take her to the hospital and doctors had to give her medications through an IV. We are worried that these convulsions can somehow harm her, although every time she seems to recover completely and is back to her normal self within a few days. Should we be more concerned about these convulsions?
Before I answer your question about potential harmful effects of convulsion, let me explain briefly about this condition for the benefit of other readers and parents out there.
Convulsion, also called seizure, is due to abnormal electrical activity of the brain. Our brain is made up of millions of nerve cells called neurons, together with many other cells that play a supportive role in the brain.
The neurons function by sending electrical signals along their nerve fibres. These nerve fibres don’t touch each other. At the end of a nerve fibre, chemicals (called neurotransmitters) are released and pass through a tiny gap called synapse so that the next nerve fibre and neuron can pick up the message and then pass on further. Although this is a rather simplistic description of the brain’s activity, it is helpful to explain it this way so that we can understand convulsions easier.
In the normal brain, many neurons in different parts of the brain generate electrical signals at any given moment. For example, if you are watching a movie, your eyes pick up images from the screen and pass along the optic nerves as electrical signal to the back side of the brain where it is registered. Similarly the ears pick up sound waves from the speaker system and convert them into electrical signals that pass through the auditory nerves to the brain. When the brain receives these signals, it may trigger certain memory or emotion.
If electrical wires were attached to your scalp at that time, these wires will pick up the electrical activities of the brain underneath. The recording is called electroencephalogram (also known as EEG). Each wire’s recording is the sum of electrical activities of many neurons in the part of the brain right underneath the wire.
Normal EEG recordings are in the form of waves. The pattern of these waves constantly change depending on the activities of the brain.
During convulsion, many neurons ‘fire off’ electrical signals at the same time. The sum of many neurons firing together will produce a larger electrical current, and appears as spikes in the EEG. If convulsion happens in one part of the brain, the spikes can be seen in this particular area, while recordings from other parts of the brain can be normal.
However, if the person has a generalized convulsion, with jerking movement of all extremities, these spikes can be seen in all regions of the brain.
There are many kinds of convulsion. It is not possible to have a full discussion here. The most common one in young children is febrile convulsion. It occurs in children between 6 months to 6 years. It appears that these children are born with a tendency to develop convulsions in response to fever. These convulsions are usually brief, lasting no more than 5 to 15 minutes.
There is no need to be excessively worried when convulsions are short. The most important thing to do is to make sure that the child doesn’t choke if vomiting does occur. The most effective way is to turn the child on the side so that any vomitus can drool out of the mouth.
During the convulsion, the child’s breathing is often noisy. This is because the child cannot control the muscle around the back of the throat, and not because he is swallowing his tongue. Never try to pry open the child’s mouth during a convulsion, you may knock off some teeth and cause an aspiration.
Most children are pale or slightly dusky during a convulsion. There is still enough oxygen going to the brain so that brain damage doesn’t occur most of the time. However, if the child’s face turns blue, or if the convulsion goes on for longer than 10 or 15 minutes, it is wise to call for emergency. The ambulance attendance has training and experience in dealing with convulsion, and they can provide extra oxygen through a face mask.
Many parents are terrified of convulsions, because their children usually lose consciousness at that time, and they can get really tired for hours afterwards. The worry of brain damage is natural, although in reality it seldom happens. Continuous ‘firing’ of electrical activity in the brain will cause electrolyte imbalance around brain cells, as well as consumption of neurotransmitters that are important in sending messages from one neuron to another. The continuous jerking movement of the arms and legs also can lead to muscle fatigue. All these factors can account for lethargy and weakness after convulsion is over. In medical term, this is called ‘post-ictal state.’
At the present time, the pressing issue for your family is to work with your doctors to find the right combination of medications and the proper dosages that will control your daughter’s convulsions. This is not an easy task. Children with frequent, and sometimes prolonged, convulsions are more difficult to manage. Careful observation and adjustment is needed to bring her condition under full control.