Anomalies of development of a brain
Anomalies of development of a brain — result of the violations of formation of separate cerebral structures or a brain happening in the pre-natal period in general. Often have nonspecific clinical symptomatology: mainly epileptic syndrome, delay of mental and intellectual development. Weight of clinic directly correlates with extent of damage of a brain. Are diagnosed antenatalno when performing obstetric ultrasonography, after the birth — by means of EEG, a neyrosonografiya and MRT of a brain. Treatment is symptomatic: antiepileptic, dehydrational, metabolic, psikhokorregiruyushchy.
Anomalies of development of a brain
Anomalies of development of a brain — the defects consisting in abnormal changes of an anatomic structure of cerebral structures. Expressiveness of the neurologic symptomatology accompanying cerebral anomalies considerably varies. In hard cases defects are the reason of antenatalny death of a fruit, they make up to 75% of cases of pre-natal death. Besides, heavy cerebral anomalies cause about 40% of cases of death of the newborn. Terms of a demonstration of clinical symptoms can be various. In most cases cerebral anomalies are shown in the first months after the child's birth. But, as formation of a brain lasts to 8-year age, a number of defects is debuted clinically after the 1st year of life. More than in half of cases cerebral defects are combined with defects of somatic bodies: congenital heart diseases, union of kidneys, polikistozy kidneys, gullet atresia and so forth. Prenatal detection of cerebral anomalies is an urgent problem of practical gynecology and obstetrics, and their post-natal diagnostics and treatment — priority questions of modern neurology, a neonatology, pediatrics and neurosurgery.
Formation of a brain
Creation of nervous system of a fruit begins literally with the first week of pregnancy. By 23rd day of a gestation formation of a nervous tube which incomplete zarashcheniye of the forward end involves serious cerebral anomalies comes to an end. Approximately by 28th day of pregnancy the forward brain bubble, in the subsequent divided on 2 side which form the basis of hemispheres of a brain is formed. Further the cerebral cortex, its crinkles, a calloused body, basal structures etc. is formed.
The differentiation of neyroblast (germinal nervous cages) leads to formation of the neurons forming gray substance and the glial cages making white substance. Gray substance is responsible for the highest processes of nervous activity. In white substance there pass various carrying-out ways connecting cerebral structures in the uniform functioning mechanism. The newborn born in time has the same number of neurons, as well as the adult. But development of his brain continues, especially intensively in the first 3 months of life. There is an increase in glial cages, a branching of neyronalny shoots and their miyelinization.
Reasons of anomalies of development of a brain
Failures can happen at various stages of formation of a brain. If they arise in the first 6 months of pregnancy, then are capable to lead to decrease in number of the created neurons, various violations in a differentiation, a hypoplasia of various departments of a brain. In later terms there can be a defeat and death of normally created cerebral substance. Influence on an organism of the pregnant woman and on a fruit, various harmful factors possessing teratogenny action is the most powerful reason of similar failures. Emergence of anomaly as a result of monogenic inheritance meets only in 1% of cases.
The exogenous factor is considered the most influential reason of defects of a brain. Many active chemical compounds, radioactive pollution, separate biological factors have Teratogenny effect. The problem of pollution of the habitat of people causing receipt in an organism of the pregnant woman of toxic chemicals has important value here. Besides, various embriotoksichesky influences can be connected with a way of life of the most pregnant: for example, with smoking, alcoholism, drug addiction. Dismetabolichesky violations at the pregnant woman, such as diabetes, and so forth, can become the reason of cerebral anomalies of a fruit also. Teratogenny action also many medicines which the woman in early terms can accept pregnancy possess, without suspecting about the processes happening in its organism. The powerful teratogenny effect is rendered by the infections transferred the pregnant woman or pre-natal infections of a fruit. The cytomegalic inclusion disease, listeriosis, rubella, toxoplasmosis are most dangerous.
Types of anomalies of development of a brain
Anentsefaliya — lack of a brain and an akraniye (lack of bones of a skull). The place of a brain is taken by soyedinitelnotkanny growths and cystous cavities. It can be covered with skin or it is naked. Pathology is incompatible with life.
Entsefalotsele — a prolapse of cerebral fabrics and covers through the defect of bones of a skull caused by its nezarashcheniye. As a rule, it is formed on the average line, but happens also asymmetric. Small to an entsefalotsela can imitate to kefalogematy. In such cases the skull X-ray analysis helps to define the diagnosis. The forecast depends on the sizes and contents to an entsefalotsela. At the small amount of protrusion and existence in his cavity of ektopirovanny nervous tissue effectively surgical removal to an entsefalotsela.
Mikrotsefaliya — the reduction of volume and mass of a brain caused by its underdevelopment. The case on 5 thousand newborns meets frequency of 1. Is followed by the reduced circle of the head and a disproportional ratio of a front/brain skull with prevalence of the first. About 11% of all cases mental retardation fall to the share of a mikrotsefaliya. At the expressed mikrotsefaliya the idiocy is possible. Not only ZPR, but also lag in physical development is often observed.
Makrotsefaliya — increase in volume of a brain and its weight. Is much less widespread, than a mikrotsefaliya. Makrotsefaliya is usually combined with violations of very tectonics of a brain, a focal geterotopiya of white substance. The main clinical manifestation — intellectual backwardness. The convulsive syndrome can be observed. The partial makrotsefaliya meets increase in only one of hemispheres. As a rule, it is followed by asymmetry of brain department of a skull.
The cystous cerebral dysplasia — is characterized by the multiple cystous cavities of a brain which are usually connected to ventricular system. Cysts can have various size. Are sometimes localized only in one hemisphere. Multiple cysts of a brain are shown by the epilepsy steady against antikonvulsantny therapy. Single cysts depending on the size can have a subclinical current or be followed by intra cranial hypertensia; their gradual rassasyvaniye is often noted.
Goloprozentsefaliya — lack of division of hemispheres therefore they are presented by a uniform hemisphere. Side ventricles are created in a uniform cavity. Is followed by rough displaziya of a facial skull and somatic defects. The still birth or death in the first days is noted.
Agiriya (smooth brain, lissentsefaliya) — an underdevelopment of crinkles and heavy violation of very tectonics of bark. It is clinically shown by the expressed disorder of mental and motor development, paresis and various forms of spasms (including Vest's syndrome and Lennox-Gasto's syndrome). Usually comes to an end with a lethal outcome on the first year of life.
Pakhigiriya — integration of the main crinkles in the absence of tertiary and secondary. Is followed by shortening and straightening of furrows, violation of very tectonics of cerebral bark.
Mikropoligiriya — the surface of bark of a brain is presented by a set of small crinkles. Bark has up to 4 layers whereas normal bark contains 6 layers. Can be local or diffusion. The last, a polimikrogiriya, is characterized by a plegiya of mimic, chewing and pharyngeal muscles, epilepsy with a debut on the 1st year of life, oligofreniy.
Hypoplasia / calloused body. Often meets in the form of a syndrome of Aykardi described only at girls. Mioklonichesky paroxysms and sgibatelny spasms, congenital oftalmichesky defects (koloboma, an ektaziya skler, ), the multiple horioretinalny dystrophic centers found at an oftalmoskopiya are characteristic.
The Focal Cortical Dysplasia (FCD) — existence in a cerebral cortex of pathological sites with huge neurons and abnormal astrotsita. A favourite arrangement — temporal and frontal zones of a brain. Distinctive feature of epipristup at FKD is existence of the short-term difficult paroxysms with bystry generalization which are followed in the initial phase by demonstrative motive phenomena in the form of gestures, trample on one place, etc.
Geterotopiya — a congestion of the neurons, at a stage of neural migration which lingered on a way of the following to bark. Heterotop ions can be single and multiple, have the nodal and tape form. Their main difference from a tuberozny sclerosis — lack of ability to accumulate contrast. These anomalies of development of a brain are shown episindromy and an oligofreniya which expressiveness directly correlates with number and the size of heterotop ions. At a single geterotopiya of an epipristupa, as a rule, debut after 10-year age.
Diagnostics of anomalies of development of a brain
Heavy anomalies of development of a brain can be often diagnosed at visual survey. In other cases allows to suspect cerebral anomaly ZPR, hypotonia of muscles of the neonatal period, emergence of a convulsive syndrome at children of the first year of life. It is possible to exclude the traumatic or hypoxemic nature of damage of a brain at absence in the anamnesis of data on a patrimonial trauma of the newborn, a hypoxia of a fruit or asphyxia of the newborn. Prenatal diagnosis of malformations of a fruit is performed by screening ultrasonography at pregnancy. Ultrasonography in the I trimester of pregnancy allows to warn the child's birth with heavy cerebral anomaly.
One of methods of detection of defects of a brain at babies is the neyrosonografiya through a fontanel. Much more exact data at children of any age and at adults receive by means of brain MRT. MRT allows to define character and localization of anomaly, the sizes of cysts, geterotopiya and other abnormal sites, to carry out differential diagnostics with hypoxemic, traumatic, tumoral, infectious damages of a brain. Diagnostics of a convulsive syndrome and selection of antikonvulsantny therapy is performed by means of EEG, and also the prolonged EEG-videomonitoring. In the presence of family cases of cerebral anomalies consultation of the geneticist with carrying out a genealogical research and the DNA analysis can be useful. For the purpose of detection of the combined anomalies examination of somatic bodies is conducted: Ultrasonography of heart, ultrasonography of an abdominal cavity, X-ray analysis of bodies of a chest cavity, ultrasonography of kidneys and so forth.
Treatment of anomalies of development of a brain
Therapy of malformations of a brain mainly symptomatic, is performed by the children's neurologist, neonatology, the pediatrician, epileptology. In the presence of a convulsive syndrome antikonvulsantny therapy is carried out (carbamazepine, to levetiratseta, valproata, nitrazepam, , etc.). As the epilepsy at children accompanying anomalies of development of a brain, usually a rezistentna to anticonvulsive monotherapy appoint a combination from 2 medicines (for example, to levetiratseta with lamotridzhiny). At hydrocephaly perform dehydrational therapy, according to indications resort to the shunting operations. For the purpose of improvement of metabolism of normally functioning brain fabrics to some extent compensating the available congenital defect performing course neurometabolic treatment with purpose of glycine, vitamins is possible. In and so forth. Nootropic medicines are used in treatment only in the absence of an episindrom.
At moderate and rather easy cerebral anomalies neuropsychological correction, the child's occupations with the psychologist, comprehensive psychological support of the child, children's art therapy, training of children of advanced age at specialized schools is recommended. The specified techniques help to impart skills of self-service, to reduce expressiveness degree mental retardation and to adapt whenever possible socially children with cerebral defects.
The forecast in many respects is defined by weight of cerebral anomaly. As an adverse symptom the beginning of epilepsy and its resistance to the performed therapy acts earlier. Existence of the combined congenital somatic pathology complicates the forecast.