is the separate form of epileptic paroxysms proceeding with short-term shutdown of consciousness without visible spasms. Can be followed by violations of a muscular tone (an atoniya, a hyper tone, a miokloniya) and simple avtomatizm. It is often combined with other forms of epileptic attacks. The basis of diagnostics is made by an electroencephalography. For identification of organic changes of brain structures cerebral MRT is shown. Treatment is performed epileptology, is based on mono - or polytherapies by antikonvulsant, is selected individually.
The first mentions about are dated 1705. The term was put into broad practice in 1824 by Absans in translation from French "absence" means what precisely characterizes the main symptom — consciousness shutdown. Among experts in the field of an epileptologiya and neurology the synonymous name "petit mal" - a small attack is distributed. enters into structure of various forms of idiopathic and symptomatic generalized epilepsy. It is most characteristic of children's age. The peak of incidence falls on 4-7 years. At most of patients it is combined with other types of epileptic attacks. At its prevalence in a clinical picture of a disease speak about absansny epilepsy.
Reasons of an absans
The imbalance of processes of braking and excitement of neurons of brain bark is the cornerstone of epileptic paroxysms. On the cause of the specified changes subdivide on:
- Secondary. Various organic defeats act as the factors causing changes of bioelectric activity: encephalitis, cerebral abscess, brain tumor. At the same time is a consequence of the main disease, treats symptomatic epilepsy.
- Idiopathic. It is not possible to establish an etiology. Assume the genetic nature of violations that is confirmed by family cases of epilepsy. Risk factors of development of a disease are the age period of 4-10 years, episodes of febrilny spasms in the anamnesis, presence of the relatives having epileptic attacks.
Can act as the triggers provoking the deep, forced breath (hyperventilation), excessive visual stimulation (light flashes, flashing of bright points), mental and physical overworks, a sleep debt (a dream deprivation). Development of an attack against the background of a hyperventilation is observed at 90% of patients.
Mechanisms of emergence of absans are definitely not installed. Results of the conducted researches indicate a joint role of bark and a thalamus in initiations of attacks, participation of the braking and exciting transmitters. Perhaps, genetically determined abnormal properties of neurons are the cornerstone of pathogenesis. Researchers consider what is formed against the background of domination of the braking activity, unlike the convulsive paroxysms which are a consequence of hyper excitement. The excessive inhibiting activity of bark can develop kompensatorno, for suppression of the previous pathological excitement. Emergence of absans at children's age and their frequent disappearance by 18-20 years demonstrates connection of a disease with processes of maturing of a brain.
can have various character, be followed by muscular and motive frustration. It formed the basis of the standard division of absansny episodes on:
- Typical (idle time) — happens shutdown of consciousness, lasting up to 30 sec. Other symptoms are absent. Light flash, a loud sound are capable to stop an attack. At easy forms of the patient can continue the activity (action, a conversation) begun to a paroxysm, but does it it is slowed down. Typical it is characteristic of idiopathic epilepsy.
- Atypical (difficult) — switching off of consciousness is followed by changes of a muscular tone, physical activity. Duration on average 5-20 sec. Attacks are typical for symptomatic epilepsies. Depending on a type of a musculomotive component distinguish atonichesky, mioklonichesky, tonic, automatic .
Symptoms of an absans
The paroxysm lasts from several to 30 seconds during which the patient loses conscious perception. From outside it is possible to notice the absent type of the patient at the time of an attack, its sudden "switching off" from activity, short hardening. Expressed proceeds with the termination of the begun action, speeches; easy — with sharply slowed down continuation of the activity preceding an attack. In the first option after a paroxysm renewal of movements and the speech precisely since that moment where they stopped is noted. Patients describe an absansny state as "a block attack", "failure", "loss from reality", "sudden dullness", "trance". During the poslepristupny period health normal, without features. Short-term typical absansa often occur imperceptibly for the patient and people around.
Difficult is more noticeable thanks to the motive and tonic phenomena accompanying it. Atonichesky paroxysms proceed with decrease in a tone of muscles that leads to lowering of hands, a ducking, sometimes — to slipping from a chair. The total atoniya causes falling. Tonic episodes are followed by strengthening of a muscular tone. According to localization of tonic changes bending or extension of extremities, the zaprokidyvany heads, a body flexure is observed. with a mioklonichesky component it is characterized by existence of miokloniya — low-amplitude muscular contractions in the form of twitchings. Twitching of a corner of a mouth, chin, one or both a century, eyeballs is noted. Miokloniya can have symmetric and asymmetric character. The avtomatizm accompanying have the nature of the repeating simple movements: chewing, potiraniye of hands, mutter, unfastening of a button.
Frequency of absans can significantly vary from 2-3rd to several tens once a day. Absansny episodes can be the only form of epileptic attacks at the patient that is typical for children's absansny epilepsy. Can dominate among different types of paroxysms (a miokloniya, toniko-clonic spasms) as at juvenile absans-epilepsy, or to enter into structure of an epileptic syndrome where other forms of attacks prevail.
The epileptic status of absans is observed at 30% of patients. 2-8 h last on average, several days can proceed. It is characterized by various degree of confusion of consciousness from the slowed-down thinking to a full disorientation and the broken behavior. The motive sphere and coordination are kept. In the speech stereotypic terse phrases prevail. In 20% of cases avtomatizm are noted. Consequences of an atonichesky absans are traumatized when falling (bruises, fractures, dislocations, ChMT). The delay and decrease in intellectual development act as serious complications (mental retardation, dementia). Their emergence and extent of progressing are connected with the main disease.
Diagnostic actions are intended to establish existence of absans and to differentiate a disease as which component they act. Detailed poll about a current of an attack of the most sick and his relatives is important. Further diagnostic procedures include:
- Survey of the neurologist. In cases of idiopathic nature of epilepsy the neurologic status remains normal. Identification of a delay of mental development, violations of cognitive functions is possible (memories, attention, thinking). At secondary genesis of paroxysms are defined focal and general neurologic symptomatology.
- Electroencephalography. EEG - the main diagnostic method. Carrying out iktalny video EEG is preferable. It is possible to register bioelectric activity in the period of a paroxysm by provocative test with a hyperventilation. During the research the patient aloud conducts calculation of quantity of breaths that allows to establish the beginning of an absans precisely. A typical EEG-pattern is existence of diffusion high-amplitude spayk and polispayk frequency> 2,5 Hz.
- Brain MRT. The research is necessary for an identification/denial of existence of the organic pathology provoking epileptic activity. Allows to diagnose cerebral tuberculosis, encephalitis, tumors, anomalies of development of a brain.
Differential diagnostics is carried out with paroxysms of focal epilepsy. The last differ in complex motive avtomatizm, difficult hallucinations, poslepristupny symptomatology; are not provoked by a hyperventilation.
Treatment of an absans
Difficulties of therapy are connected with resistance emergence. In this regard an important point is the differentiated approach to purpose of antikonvulsant according to a look and an etiology of paroxysms.
- Monotherapy of the typical absans acting as the only type of epipristup is carried out valproyevy to - that, etosuksimidy. These medicines are effective at 75% of patients. In resistant cases it is recommended to combine monotherapy with small dosages of a lamotridzhin.
- Monotherapy of the combined idiopathic forms of epilepsy where typical absansa are combined with other options of attacks, demands purpose of antikonvulsant, effective concerning all types of the available paroxysms. Valproata, to levetiratseta which influence both absansa, and mioklonichesky and toniko-clonic attacks are used. At a combination of absans and toniko-clonic convulsive paroxysms it is effective .
- Monotherapy of atypical absans is performed by valproyevy acid, lamotridzhiny, fenitoiny. Quite often positive effect gives a combination to steroid therapy. Tiagabin, carbamazepine, phenobarbital can aggravate symptomatology. Often atypical absansa are badly stopped by one medicine.
- Polytherapy is necessary in cases of weak efficiency of monotreatment. Selection of a combination of antikonvulsant and a dosage is made epileptology individually, depending on a disease.
Gradual decrease in a dose of an antikonvulsant and cancellation of antiepileptic therapy are possible against the background of permanent remission within 2-3 years. Secondary cases of epilepsy need therapy of a basic disease and symptomatic treatment. If the epileptic syndrome proceeds with decrease or defective development of cognitive abilities, occupations with the psychologist, neuropsychological correction, comprehensive psychological support are necessary.
Forecast and prevention
Success of antiepileptic treatment depends on a disease. In most cases children's idiopathic absansa pass to 20-year age. Juvenile absansa remain at adult age at 30% of patients. Worse the forecast at Lennox-Gasto's syndrome differing in resistance of epipristup and the progressing frustration of the cognitive sphere. The forecast of secondary paroxysms completely depends on efficiency of treatment of causal pathology. Prevention comes down to the prevention and timely treatment of organic cerebral diseases, an exception of impact on a fruit of various teratogenny influences capable to cause structural anomalies of a brain, genetic disorders.