Amielia (amyelia - and - Greek. myelos marrow) - complete absence of the spinal cord with preservation of the Dura mater and spinal ganglia. In place of the spinal cord is sometimes a thin fibrous cord. Usually combined with acrania, anenzephalia, the splitting of the spinal canal.
Infants who are born with this condition, there are no specific parts of the brain, and other parts covered with a cloth, and remain in their infancy. This pathology is characterized by the fact that the newborn has no both hemispheres of the brain. Sometimes the missing tissue of the cerebral hemispheres replaces the abnormal tissue from another part of the brain. Although these reflexes, like breathing, response to sound and tactile response may be present, but the mental part remains undeveloped. The body of a child develops normally.
In 1891 Chiari (Chiari) identified four types of anomalies with their detailed presentation. This classification physicians are present. 1. Anomaly Arnold-Chiari malformation type I is a prolapse of posterior fossa structures in the spinal canal below the plane of foramen Magnum. 2. When anomalies Arnold-Chiari type II - occurs caudal dislocation of lower segments of worm, the medulla oblongata and fourth ventricle, often develop hydrocephalus. 3. Anomaly Arnold-Chiari type III is rare, characterized by gross caudal displacement of all the structures of the posterior cranial fossa.
Defect is accompanied by aplasia perforated plate of the ethmoid cost and cockscomb, absence or hypoplasia of direct convolutions of the frontal lobes. Arhinencephaly may occur in the form of an isolated defect, but more often is an integral component of some genetic and chromosomal syndromes, in particular of Meckel syndromes and Patau.
Common arterial trunk refers to congenital heart defects – it occurs when the fetus is in the womb. It can be caused by the effects on the pregnant negative factors, especially in the first trimester of gestation. Among the dangerous factors that trigger the disease, secrete diseases pregnant.
The most noticeable symptom of hydrocephalus is unusually large head, it is noticeable at birth or in the first 9 months of life. It should also be noted that in the first years of life the baby's head is very much increased. That is why doctors can start to worry only when the head size increases faster than the child grows and gains weight. Also soft places on the head (fontanel) may harden or bulge outward.
Although the relationship of heredity and frequency of spinal hernias pointed out by the researchers of the XIX century, the true interest of geneticists to this problem have emerged in the last decades of the twentieth century. Currently the concept of "spinal dysraphia" unites various developmental disorders of the spinal cord and spine: - spina bifida occulta - hidden cleft spine- - spina bifida cystica uverta - open spina bifida with formation of cystic spina bifida- - rhachischiasis posterior (totalis et partialis) - splitting of the spine and soft tissues with the spreading of the spinal cord that occur throughout the spine, or only in some parts.
Clinical manifestations of diastematomyelia combines the features of primary myelodysplasia and symptom that develops as the child grows, in the process destroying the natural proximal migration of the spinal cord in its fixing partition. Noticeable at an early age (before 3 years) spinal deformity researchers met in 62 cases. Prevailed scoliotic deformity (42), kyphosis and kyphoscoliosis deformation was less frequent (20)
Less than 25 cases the hernia protrudes through the front of the skeleton, usually in the forehead or between the eyes (both of these forms are called frontal hernia of the brain). If the encephalocele is located in the forehead, it can shift the orbit, resulting in in patients with wide-set eyes. If the anomaly is located between the eyes, we observed the expansion of the bridge of the nose, although sometimes a hernia can only be noticed in the study of the nasal passages, that is, outside the defect is completely invisible. Often mistaken for a hernia nasal polyp (see polyp), the result is a wrong diagnosis and hernia of the brain remains unrecognized.
Big brain remains the single education and ventricular system consists of one common cavity. Usually there are other anomalies: arhinencephaly - aplasia of the olfactory tracts and olfactory brain in General - cyclopia - the presence of only one eye, located in the midline.
The spinal canal is expanded, lined with ependymal and is filled with cerebrospinal fluid. Usually the thinner sections of the spinal cord in the back of the pillars, resulting in the neurons of the gray matter in hydromyelia almost never suffer from.
H. Lewis singled out two main groups: iniencephaly slit, with the formation of brain herniation, and iniencephaly closed, in which there is damage to the spine in the absence of brain herniation. The frequency of pathology ranges: 0,1-10:10,000 and above, depending on the possibilities of diagnostics of a syndrome. Iniencephaly more common among female fetuses - M:F=1:104. This pathology differs from anencephaly is iniencephaly closed anterior part of the brain tube. Microscopic examination of the brain reveals a number of anomalies, "including microencephaly, polymicrogyria, heterotopic glial tissue in the meninges, atresia ventricular system, pronounced disorganization of the brain stem and the spinal cord tissue, large cerebellar cyst".
Cephalonia (SYN.: microencephaly, megalocephaly) – unusual increase in mass and dimensions of the brain, accompanied by disturbances of the location of the brain, changes in the cytoarchitectonics of the cortex, lesions of heterotopias in the white matter, enlarged skull. Cephalonia (megalocephaly) - increase the weight and size of the brain more than 2 standard deviations, which is accompanied by violation of the position and size of the convolutions, changes in the cytoarchitectonics of the cerebral cortex and neuronal heterotopias in the white matter, as well as frequent anomalies of the cerebellum and cerebrospinal fluid pathways.
The mass of the brain in microcephaly is dramatically reduced, sometimes up to 500 - 600 g. In the brain show signs of gross malformations: the macro and microgyria, lissencephaly, agentii corpus callosum, heterotopia. Especially reduced frontal and temporal lobes of the brain, so the island remains undisguised. Convolutions flattened, there are no tertiary gyrus and sulcus. The basal ganglia compared with the cerebral cortex is more developed.
Doctors distinguish three forms of spina bifida: - Spina bifida occulta. Often this form is called "hidden spina bifida" because in this case the spinal cord and nerve roots were normal, and there is no defect in the back. This form is characterized by only a small defect or gap in the vertebrae that form the spinal column. Often this form of pathology is so mild that does not cause any worries. At this stage, patients are not even aware of the presence of this malformation and learn about it only after radiography.