Temporal lobe epilepsy
Temporal lobe epilepsy is a form of epilepsy in which there is a periodic recurrence of unprovoked seizures, and the focus of epileptic disease is located in the temporal lobe of the brain. Temporal lobe epilepsy (psychomotor epilepsy) it is considered the most common form of epilepsy, belongs to a heterogeneous group in which the clinical picture determines the focal nature of the disease and the location of the epileptic focus in the temporal lobe of the cerebral cortex.
The content of the article:
Causes of temporal lobe epilepsy
Classification of temporal lobe epilepsy
Symptoms of temporal lobe epilepsy
Diagnosis of temporal lobe epilepsy
Treatment of temporal lobe epilepsy
Prognosis of temporal lobe epilepsy
Temporal lobe epilepsy
There are two types of temporal lobe epilepsy — medial and neocortical. Medial temporal epilepsy is determined by the location — the hippocampus, characterized by such a sign as hippocampal sclerosis. Neocortical temporal lobe epilepsy affects the outer part of the temporal lobe of the brain and is considered less common than medial.
Causes of temporal lobe epilepsy
A number of factors can provoke the development of this disease. In some cases, the epileptogenic discharge does not occur in the temporal lobe of the brain itself, but comes there from other areas of the main organ of the central nervous system.
All the reasons can be divided into two groups:
Perinatal (prematurity, fetal hypoxia, etc.).
Postnatal (allergies, alcohol dependence, circulatory disorders, vitamin deficiency, metabolic disorders, severe intoxication of the body).
Causes determining the occurrence and development of temporal lobe epilepsy:
birth injuries;
fetal hypoxia;
intrauterine infection (syphilis, rubella, etc.);
asphyxia of a newborn baby;
traumatic brain injuries;
neuroinfections (purulent meningitis, encephalitis, post-vaccination encephalomyelitis, neurosyphilis);
tumor of the temporal lobe of the brain;
vascular malformations;
hemorrhagic and ischemic stroke;
brain infarction;
tuberous sclerosis;
intracerebral hematoma;
cerebral vascular aneurysm;
aneurysm or glioma;
cortical dysplasia (congenital pathology of the cerebral cortex).
One of the main reasons for the development of temporal lobe epilepsy, scientists and doctors call postpartum trauma, in which neurons die. This phenomenon occurs as a result of hypoxia, ischemia, as well as damage due to contact with neurotransmitters. Sometimes there is the occurrence of temporal epilepsy together with febrile convulsions that last for a long time, the development of mediobasal temporal sclerosis, the occurrence of which is the subject of discussion and has not been fully clarified.
The probability of hereditary transmission of the disease is low. A child may get more predisposition to temporal lobe epilepsy when exposed to certain factors.
Classification of temporal lobe epilepsy
In order to make a more accurate diagnosis of temporal lobe epilepsy and, as a consequence, to prescribe adequate treatment, it is necessary to differentiate the type of temporal lobe epilepsy. For this, there is a classification of this disease.
Temporal lobe epilepsy is divided into four types:
Lateral.
Amygdalar.
Hippocampal.
Opercular (insular).
Sometimes amygdalar, hippocampal and insular are combined in one group — amygdalogippocampal. Some scientists distinguish another type of temporal lobe epilepsy — botemporal (when the foci of the disease are localized in both temporal lobes of the brain). This type of temporal lobe epilepsy can develop either simultaneously in both temporal lobes, or according to the principle of a mirror (the focus appears and develops first in one temporal lobe, and eventually passes into the second).
Symptoms of temporal lobe epilepsy
Signs of temporal lobe epilepsy may initially be invisible, this is the danger of the disease. Temporal lobe epilepsy can be observed at any age and directly depends on the causes that provoked its origin.
Seizures with temporal lobe epilepsy are divided into three types
Simple partial seizures (aura)
They proceed without disturbing the patient’s consciousness, often preceded by other, more complex partial seizures. Olfactory and gustatory seizures often accompany temporal lobe epilepsy (a feeling of unpleasant odors and tastes). Sometimes there is an involuntary turn of the eyes towards the localization of the focus of epilepsy, arrhythmia or chills. Patients complain of an unexplained feeling of fear and hopelessness, distorted perception of time and shapes of objects, and sometimes the distance to them, visual hallucinations are present. In some cases, derealization is observed (a feeling of unreality of the surrounding world, a feeling that familiar objects or people seem completely unfamiliar and vice versa — when an unfamiliar environment seems familiar). In some cases, there is depersonalization (the patient gets confused in his thoughts and believes that the body and thoughts do not belong to him, he can see himself from the outside). The twilight state can be both short-term and long-term (sometimes the duration is several days).
Complex partial seizures
They pass with a violation of the patient’s consciousness and automatism (unconscious actions during seizures). It is often possible to observe repetitive chewing or sucking movements, smacking lips, frequent swallowing, patting, various grimaces, inarticulate muttering or repetition of individual sounds. Restless hand movements (nervous rubbing, convulsive sorting of objects). Automatism is sometimes similar to complex conscious movements — driving a car or traveling on public transport, actions that may be dangerous for others and for the patient himself, articulate speech. During such an attack, the patient is unable to respond to external stimuli, for example, to appeal to him. A complex partial attack lasts about two to three minutes. At the end of the attack, the patient does not remember what happened to him and feels a strong headache. In some cases, it is possible to observe a loss of motor activity or a slow fall without convulsions.
Secondary generalized seizures
They are observed with the progression of the disease. During such attacks, the patient loses consciousness and is paralyzed by convulsions in all muscle groups. As it progresses, temporal lobe epilepsy leads to complex mental and intellectual disorders. There is a deterioration of memory, slowness in movements, emotional instability, aggressiveness. The frequency and severity of seizures in temporal lobe epilepsy are variable and varied, characterized by spontaneity. The female body may react with a violation of the menstrual cycle. Symptoms of temporal lobe epilepsy may manifest as symptoms of other diseases, which complicates the diagnosis of the disease.
Diagnosis of temporal lobe epilepsy
Diagnosis of temporal lobe epilepsy is quite complicated, especially in adults. Often a person does not know the symptoms of this disease, so he may simply not be aware of its presence. A person simply does not pay attention to simple partial seizures, but turns to a doctor already when complex seizures occur, which makes it difficult to diagnose and, accordingly, treat the disease. In addition, when diagnosing temporal lobe epilepsy, it must be differentiated from the usual epileptic disease or from a tumor in the temporal region, which is also accompanied by epileptic seizures.
The most informative way of diagnosis is an electroencephalogram. With temporal lobe epilepsy, the patient is characterized by normal indicators if the study was conducted in the period between seizures. The veracity of the data depends on the depth of localization of the epilepsy focus. If it is located deep in the structures of the brain, then the examination can also show the norm even during the attack itself. For higher accuracy of the examination data, invasive electrodes are used, and sometimes electrocorticography (electrodes are applied directly to the cerebral cortex). In most cases (more than 90%), the electroencephalogram is able to detect changes at the time of the attack.
Treatment of temporal lobe epilepsy
Treatment of temporal lobe epilepsy is complex and has many directions. First of all, it is necessary to reduce the frequency and strength of seizures, achieve remission, and improve the quality of life of the patient.
Medical treatment
Conservative therapy consists in the use of drugs carbamzepine, phenytoin, valproates, barbiturates. Treatment begins with monotherapy — a dose of carbamzepine is prescribed, which gradually increases to 20 mg, in some cases up to 30 mg per day. If the patient’s condition does not improve, the dose may be increased until the results improve or signs of intoxication appear (while taking the drug, doctors monitor the concentration of carbamzepine in the patient’s blood). In complex cases of secondary generalized seizures, the drug diphenin or depakin (valproate) is prescribed. Doctors believe that the effect of valproates is better than diphenine, especially since the latter has a much more toxic effect on the body, especially on the cognitive system.
There is the following system of priority of prescribing medications for temporal lobe epilepsy:
carbamzepine;
valproates;
phenytoin;
barbiturates;
polytherapy (with the use of basic antiepileptic drugs);
lamotrigine;
benzodiazepine.
Polytherapy is used only if monotherapy is ineffective. Multiple combinations of basic and reserve antiepileptic drugs are possible. A decrease in seizures is observed when taking phenobarbital with diphenine, but this combination can significantly affect the central nervous system, having an inhibitory effect that provokes ataxia, cognitive decline, memory impairment, and negatively affects the gastrointestinal tract.
Drug therapy requires lifelong medication and careful monitoring by doctors. In about half of the cases, it is possible to completely stop seizures with the help of properly selected drugs.
Surgical intervention
In case of ineffectiveness of conservative therapy, intolerance of basic antiepileptic drugs even in the smallest permissible doses, an increase in epileptic seizures that disadapt the patient, resort to surgical treatment. For surgical intervention, a mandatory factor is the presence of a clear epileptogenic focus. Surgical treatment is highly effective: about 80% of patients experience a significant decrease in the frequency and strength of seizures after surgery. In half of the operated patients, seizures disappear altogether, social adaptation improves, intellectual functions return. It is not recommended to resort to surgical intervention in case of severe general condition of the patient, severe mental and intellectual disorders. Temporal lobe epilepsy, the treatment of which is a complex and ambiguous procedure, requires constant monitoring by doctors.
Preoperative examination involves all possible types of neuroimaging (electrocorticogram, video EEG monitoring, passing tests to identify the dominance of the brain hemisphere).
The task of a neurosurgeon is to eliminate an epileptogenic focus and prevent the movement and spread of epileptic impulses. The essence of the operation is a temporal lobectomy and removal of the anterior and mediobasal parts of the temporal region of the brain, uncus, basolateral amygdala. There are risks during such an operation, and the patient should be informed about possible complications. Complications include Kluver-Bucy syndrome (hypersexuality, loss of a sense of modesty and fear), hemiparesis, mnestic disorders, complications after anesthesia.
Prognosis of temporal lobe epilepsy
The prognosis of temporal lobe epilepsy depends on the volume of brain damage. Timely and adequate treatment gives a fairly high chance of stopping seizures and a successful result. Drug therapy is effective with further remission in no more than a third of all patients. Most of them have a deterioration in their condition, an increase in seizures and difficulty in social adaptation. In most cases, patients need neurosurgical treatment.
