Epilepsy is a common problem seen in 1% of adults and 0.4-0.8% of children. By definition epilepsy is when a person develops two or more unprovoked seizures. To understand this better, we first need to learn what is meant by a seizure.
A “seizure” or “fit” as it is known in lay terms, is an abnormal manifestation which may take the form of a body movement (motor), change of / feeling of an abnormal sensation (sensory) or change in autonomic features such as change in heart rate, respiratory rate or pupil size etc. that occurs due to an abnormal electrical discharge in the brain. Of those who have their first seizure, only 35% go on to develop subsequent seizures.
Therefore, an individual who develops recurrent seizures (two or more) without any provocation is considered to be suffering from “epilepsy” and would be termed an “epileptic”.
Epilepsy occurs when the brain’s electrical discharges fire in an unwanted manner episodically and this gives rise to a) unusual body movements such as becoming stiff, clonic jerking, weak or doing uncontrolled movements or b) unusual sensations such as abnormal feeling, seeing unusual things, hearing abnormal sounds and feeling unusual tastes/ smells etc and or c) heart rate increase, respiration weakening, pupils becoming large, colour change on face etc.
There are different types of epilepsies. In medical terms these different types are grouped into broad categories which are called “epilepsy syndromes”. This division is based on several factors including the changes that occur, the associated EEG findings, family history, the age of onset, how they respond to treatment etc. Therefore if your child or someone known to you develops any of the above features, it is very important to note them carefully. It is your clear description that will help your physician to decide on the underlying broad epilepsy group.
Once epilepsy is diagnosed, what is the next step?
All epilepsies do not occur in the same manner. In some the patient does not lose awareness but is unable to control the unusual body movement or abnormal sensations. In some forms, the patient becomes unconscious and may have violent jerky movements. Some seizures occur almost daily while others occur very rarely. Some last a few seconds while others last even up to 30-60 minutes. Some cause reduction of breathing. Some disappear after a certain age group while others may occur life-long. Some occur infrequently initially but become very frequent later on. Therefore, the impact of your epilepsy and the need to treat it will entirely depend on the underlying epilepsy syndrome.
In children, the commonest epilepsy syndrome is known as Benign Rolandic Epilepsy. This manifests as a focal seizure occurring from sleep during which there is jerking of limbs on one side of the body and the child is unable to speak. This type of epilepsy occurs very infrequently; may be twice or thrice only and disappears after a certain age even without treatment. Such children often can be watched even without being treated with anticonvulsants.
On the other hand an otherwise healthy adult who develops similar focal seizure with jerking on one side and who is found to have an abnormal area in his brain on imaging may develop frequent seizures causing impact on his employment. He may require regular anticonvulsant therapy.
Therefore once the diagnosis of epilepsy is confirmed the next steps would be:
a) Establish the epilepsy syndrome
b) Plan necessary investigations
c) Decide on the best form of therapy.
What investigations
should be done?
In a patient suspected of having epilepsy, an electroencephalogram (EEG) is essential. This is a brainwave tracing, recording the electrical activity generated from the brain surface. This will show typical abnormalities in some types of epilepsies. On the other hand since the recording is limited to 20-30 minutes, an abnormality may not be captured during this time span. Further, some epilepsies such as those arising from a very small area of brain or those situated deep may not show abnormalities at all. Therefore a normal EEG does not exclude epilepsy.
The next useful investigation is neuro-imaging. This is mainly for those who have epilepsy arising from one side of the brain. For this the investigation of choice is a MRI of the brain. This shows the structure of the brain as viewed from different planes. This scan is performed using magnetic fields therefore does not cause any radiation or harm to the patient. This will enable the clinician to detect any abnormal areas of the brain such as congenital abnormalities, old scars, cerebral malformations etc.
How do we treat epilepsy?
The decision to treat is taken considering the epilepsy type as well as patient expectations. Some epilepsy types need not be treated constantly. For instance in Benign Rolandic Epilepsy which mainly occurs in sleep and infrequently, the children stop having seizures after a certain age limit. In some others treatment may be commenced even after the first episode such as in the case of a mason who climbs on to scaffolding.
Epilepsy is treated using medications broadly known as ‘anticonvulsants’ or antiepileptics. Their mechanism of action is only to control the seizures; they will not eradicate the underlying epileptogenic lesion. However, 60-70 % of epileptic patients can become seizure-free on single or multiple anticonvulsants.
Good seizure control can be achieved by using a single agent in close to 50 percent. Adding a second may increase this by further 10-15 percent. A third will add another 5% but adding anticonvulsants beyond this number is not beneficial to the patient. At this point the Dr. will try to find the best combination that will give the best control; having a minimal number of seizures.
How long should
anticonvulsants be taken?
If the epilepsy is controlled with anticonvulsants and if the epilepsy is an idiopathic epilepsy generally anticonvulsants are continued up to two years. If the epilepsy is due to an underlying structural lesion, certainly the possibility of taking the patient off medication after two years can be considered. These epilepsies have a higher chance of recurrence.
In general most epilepsies are easily treatable and the patients have a good outcome in a majority. |
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