Epilepsy is a (neurological) disease of the central nervous system, when activity of nervous cells in brain is damaged, causing seizures. During seizures person has changed behaviour, experiences unusual symptoms and sensations, including unconsciousness. This episodic attack can be short (several seconds, minutes) or long (mainly, convulsive seizures).
1% (65 mln.) of the world’s population has epilepsy. With age, manifestation frequency increases. New cases in developed countries are especially often among infants and elderly, while in developing countries – in late childhood and early teens which is presumably preconditioned by chronicity of infant and child epilepsy (due to incorrect treatment).
According to US data, out of 100 people 1 is likely to have one non-provoked (caused by any factor) seizure during lifetime. However single seizure does not mean epilepsy. Only in case of 2 non-provoked seizures (type not specified) epilepsy is diagnosed.
Due to the fact that epileptic seizure is caused by pathological discharge developed in brain cells, it can damage any process which is coordinated by brain. Seizure can manifest the following transitional (generally self-stopping) symptoms:
- Confusion (disorientation in time and environment)
- Speech standstill
- Uncontrolled convulsive movements of hands and legs
- Loss of consciousness or vigilance
- Psychic symptoms (change of behaviour and thinking)
- Symptom manifestation depends on seizure type. In the majority of cases a person with epilepsy has seizures of one type, correspondingly every next episode symptoms are similar.
- Doctor classifies seizures according to how pathologic activity in brain begins (focal, i.e. local, or generalized which involves the whole brain).
Classification is conducted by evaluation of the type of seizure, causing reason, epileptic syndrome and the condition which accompanies seizure. The new project of epileptic seizures and syndromes classification 2001 includes the list of diseases which are associated with epileptic seizures.
Seizure preconditioned by a pathologic discharge in one of brain areas is called focal (partial). Two types of focal seizures are defined (however according to the new classification this division is not recommended, while the types are difficult to be distinguished from each other):
- Common focal seizure: doesn’t cause change of consciousness. An attack change of emotion, item configuration, taste, smell, perception can happen at the moment of seizure. Involuntary contractions in any body part are also possible, for example, in hand or leg; spontaneous manifestation of sensor symptoms, such as numbness, giddiness or twinkling light.
- Discognitive focal seizure: causes change and possible temporary loss of consciousness or vigilance. Such seizure is often revealed by a dumbfounded look, aimless movements – such as hand squeezing, aimless walking, chewing and swallowing movements.
Seizure which is expanded to the entire brain is called generalized. There are 6 types of generalized seizures:
- Absence – so-called petit mal, characterized with staring and slight vibration in the body. Can cause short loss of consciousness.
- Tonal seizure – causes muscle tension, mainly including back, hand and leg muscles, can cause drop.
- Clinical seizure – characterized by rhythmic, interrupted muscle contraction. Mainly includes neck, face, hands.
- Myoclonic seizure – sudden short contractions in hands and legs.
- Atonic seizure – so-called drop seizure, causes loss of muscle control, sudden drop is possible.
- Tonic-clonic seizure – so-called grand mal; characterized by consciousness loss, body contraction, sometimes followed by tongue biting and involuntary urination.
More than 2/3 of epileptic seizures begin in childhood (mainly in the 1st year of life). Seizure manifestation in this age group is especially diverse, which is explained by immaturity of brain.
In 50% of cases reasons causing epilepsy are not identified, while among 50% of patients with epilepsy it is associated with different factors:
- Genetic influence – some cases of epilepsy, defined in the list of seizure types, can be found in the family. In these cases a genetic predisposition seems to have place.
- Researchers connect certain cases of epilepsy to specific genes; it is defined that more than 500 genes can be associated with this condition. In the majority of cases genes can be a constituent part of reasons for epilepsy. Main genes can predefine person’s sensitivity towards those environmental factors which are seizure triggers.
- Head trauma – a head trauma (as a result of accident or other traumatic damage) can become a reason of epilepsy.
- Different conditions of brain – conditions of brain damaging it, such as tumor or stroke, can cause epilepsy. Stroke can become a reason for epilepsy after the age of 35.
- Infectious diseases – meningitis, AIDS, viral encephalitis can cause epilepsy.
- Prenatal damage – a child’s brain can be damaged before birth, while in womb, due to various factors. These factors are, for instance, mother’s infection, bad nutrition or lack of oxygen. Such brain damage can cause epilepsy and cerebral palsy.
- Progressive damages – epilepsy is sometimes associated with such progressive disorders as are autism or neurofibromatosis.
In order to evaluate patient’s condition doctor conducts evaluation of symptoms and medical history (anamnesis). Several examinations must be conducted to diagnose epilepsy and reasons causing seizures:
- Neurological examination – doctor evaluates behaviour, kinetic skills, mental functions and functioning of other brain areas, in order to evaluate patient’s condition, define type of epilepsy.
- Blood test – to define infection, genetic or other condition that could have caused seizures.
In order to identify possible brain damage, doctor defines the necessity of conducting various tests:
- Electroencephalogram (EEG) – the most important examination for diagnosing epilepsy. Electrodes are fixed on head skin with the help of jellylike matter, which record brain’s bioelectric activities.
If patient has epilepsy, there is a big probability that the normal brain waves pattern will be damaged even when there is no seizure at the moment of test. In ambiguous cases it is reasonable to perform EEG recording together with video monitoring for long periods during sleep and being awake, in order to register a seizure. An EEG recording of a seizure simplifies diagnostication. Sometimes, with the aim of provoking seizure, sleep deprivation (decrease of sleep duration) is conducted before EEG examination upon doctor’s instructions.
- Computer tomography (CT) – this equipment uses X-rays to receive layered image of brain. It shows the damages which can be the reason of seizure – mainly, tumor, hemorrhage, cysts.
- Magnetic Resonance Image (MRI) – magnetic and radio waves are used to define nidus of brain damage, causing seizures.
- Positron Emission (PET) and Photon Emission Computer Tomography (SPECT) – this method is based on better revelation of brain damage by image of blood circulation in brain matter directly during seizure, as a result of injection of small doses of radioactive matters in vein.
- Neuropsychological examination – special examination (for children, teenagers) to evaluate patient’s thinking, memory, behaviour and speech, which helps revealing damaged areas of brain.
Doctor usually starts epilepsy treatment with medicine. If medicine doesn’t prove effective, surgical or other type of treatment is possible to be discussed.
Medicine (antiepileptic drugs) – the majority of patients are freed of seizures upon intake of one antiepileptic drug, some of them have reduced frequency and intensity of seizures. The issues of treatment duration and drug withdrawal are decided by doctor.
More than 50% of children with epilepsy are released of seizures, treatment is withdrawn and they live without seizures for the entire life. Among teenagers it is also often possible to withdraw drugs after 2 or more years without further resumption of seizures.
Correct adjustment of medicine and dose can be difficult. Before starting treatment doctor takes into consideration patient’s condition, type of epilepsy, seizure frequency, age and other factors. In case of intake of other medicine, doctor also takes into consideration their interaction with the antiepileptic drug.
As a rule treatment starts with one medicine, comparatively low dose, then gradual increase of dose takes place until seizures are over.
Antiepileptic drugs can have side effects (slight or comparatively heavy). In order to completely cease seizures through successful treatment, the following must be taken into consideration:
- Medicine must be taken exactly upon doctor’s prescription.
- Doctor must be informed about replacement of an antiepileptic drug by a substitute (so-called generic), intake of other medicine, herbs or non-traditional means.
- Treatment can’t be withdrawn without doctor’s consent.
- Doctor must be immediately notified about unusual condition, change of mood or behaviour.
Approximately half of newly diagnosed cases of epilepsy are released from seizures upon receiving one medicine. In case of non-efficiency of treatment, doctor decides the issue of further treatment tactics.