Malformations

Malformations (synonym anomalies of development) is a collective term for deviations from the normal structure of the organism as a result of violations of prenatal or postnatal (less) development.
The greatest value of malformations have congenital defects formed during the prenatal period. The term "birth defects" should be understood persistent morphological changes outside of structure variation of a normal organism.
The term "defect of development" or the violation of development not only in utero and postnatal (defects of teeth, outdoor arterial canal).
"Ugliness" should be called such birth defects, which disfigures part or all of the body and is found at external examination. Better this term in relation to living people not to use.
Malformations can occur as a result of hereditary factors (see Hereditary diseases) or exposure to harmful factors directly on emerging embryo and fetus (see Fetopathy, Embryopathy). The factors that cause birth defects, diverse: alcohol, chemical-pharmaceutical preparations, oxygen starvation, ionizing radiation, diabetes mother, viral and parasitic diseases maternal and fetal (such as cytomegalovirus, Toxoplasma, epidemic hepatitis, rubella, etc.). Many of the causes of the formation of defects in humans has not been settled, the Impact of harmful factors in the period of embryogenesis, when formed: the authorities, leads to death of the tissues and the emergence of persistent violations and gross deformations, manifested by the absence of a body (see; Agenesia), its underdevelopment (hypoplasia) or excessive development (hyperplasia). In the fetal period, when will organogenesis, the processes of maturation functions and tissues of the fetus, there are less gross malformations in the form of violations of the fine structure.

Siamese twins photo
Fig. 1. The twins are connected sciatic parts of the body. Fig. 2. To the sacral parts of the body attached immature fetus isa parasite.

Fig. 3. The absence of a large brain: Fig. 4. Absent limbs

There are malformations of single and multiple (usually double); malformations of the external parts of the body and internal organs. Double malformations - twins fused any parts of the body (Fig. 1). When you double: asymmetric defects on the surface or in any body cavity of the child is attached to another (underdeveloped) the fruit, a so - called parasite (Fig. 2). Malformations observed in the form, abnormalities of the head (Ucrania, brain: hernia), persons (cleft lip, cleft palate, cyclopia), body (spina bifida), extremities. - no one, of all or underdevelopment of the extremities (cassocks. 4). The most frequent defects of the musculoskeletal system: congenital dislocations, clubfoot, underdevelopment fingers and other internal organs are often found malformations cardiovascular system (see the Vices of the heart) and malformations of the Central nervous system: congenital hydrocephaly, microcephaly, anencephaly (Fig. 3). In the digestive system may complete closure (see Atresia) or narrowing of the digestive tube and bile ducts, the correct position of the intestine and its parts. Malformations of respiratory organs are often manifested in the form of improper formation of the bronchial tree; the Most common malformations urogenital system: aplasia (hypoplasia) one kidney, horseshoe kidney, congenital hydronephrosis (see), cryptorchidism (see), bicornuate uterus, false hermaphroditism (see).
When malformations incompatible with life, an important early diagnosis, as some of them can be corrected by surgery. Prevention of defects must be carried out along the lines of the protection of pregnant women against harmful to the fetus external influences - see Antenatal care of the fetus.

Malformations (synonym: abnormalities and deformities) - birth defects, deviations from the normal structure of the body.
The science that studies ugliness, is called teratologia (from the Greek. teras, teratos ugly, ugly). The terms "ugliness" and "defects" are used as synonyms, but sometimes the most light extent P. R. called abnormalities, and the most severe (usually accompanied by the disfigurement of the external appearance) - deformities. In most cases, the disease development is a consequence of embryopathy (see), while fetopathy (see). Modern teaching about etiology and pathogenesis of P. R. appeared on the base of success of embryology, genetics and experimental teratology.
For every thousand births account for an average of about 10 children with developmental defects. Among perinatal deaths, postmortem data, P. R. logged in to 8.5 by 14% of cases.
Morphological characteristics. There are single malformations (violation of forming one body) and double (wrongness development twins). First distinguish localization: anomalies of the head (Fig. 1), torso, limbs (Fig. 2), the system of internal organs. Double ugliness can be free or connected with this kind of connection can be symmetrical (Fig. 3 and 4) and asymmetric. In an asymmetric connection is one of the fruits (AutoIt) developed correctly, but it connects to other undeveloped fetus (parasite). Quite rudimentary, the parasite can be inside autosite (inclusio foetalis).
Malformations can be manifested by the absence of a body (agenesia, aplasia), its underdevelopment (lipogeneza, hypoplasia) or excessive development (giperkinesia, hyperplasia), the closure of the channel or holes (atresia, for example atresia anus), merge bodies or members (syndactylia; horseshoe kidney), preservation of embryonic structures (Meckel's ganglion diverticulum, open arterial duct, many forms of congenital heart defects, cleft embryonic slots (cleft lip, spine), offset organs or tissues, etc. one
of the twins might be missing heart, my head or limbs.
United double malformations occur in identical twins during the early gastrulation by dividing the end of the embryo or through the merger of two embryos. Each malformation may occur only in a certain (so-called critical) the period of embryogenesis, when there is a formation of the relevant body (Fig. 5). Under the influence of any hazards on the embryo such period as svalbe (I.e. Schwalbe), can become teratogenesis termination period.
Etiology P. R. different. We can distinguish two main groups etiologic factors.
A. Genetic factors (family history, perezrevshie germ cells parents, violations of chromosomal apparatus of germ cells in connection with the age of the parents, and others). In the basis of hereditary malformations lies mutation (see) germ cells ancestors; it can cause ionizing radiation and chemical exposure. Perezrevshie sex labels is prolonged (up to two days) finding the eggs or sperm in the genital tract women, where these cells can be damaged. There are indications that the elderly parents of children with P. R. born more frequently, depending violations exactly chromosome apparatus germ cells parents.


B. Factors, impacting directly on the developing embryo or fetus); physical (radiation, mechanical, thermal, and chemical (hypoxia, hormonal decorrelation, malnutrition, teratogenic poisons) and biological (viruses, bacteria, protozoa), as well as psychological trauma of his mother, indirectly cause harm to the embryo or fetus).
Physical factors most teratogenic importance to ionizing radiation. Even small doses of radiation can sometimes cause teratogenic effects. Mechanical damage to the embryo or fetus) is most often seen when amniotic the growths. Thermal effects in experiment, even short-term, also have a teratogenic effect.
Of the chemical impact of the highest importance hypoxia caused by different reasons. From hormonal disorders, leading to the development defects, the most studied diabetes. Hormonal drugs, derived by the mother during pregnancy, malnutrition (lack of vitamins, amino acids, trace elements) can also lead to P. p. In experiment permanent teratogenic means proved Tipanova blue. Recently has the same effect sedatives thalidomide. Described teratogenic effects and many other chemical agents, including drugs (in particular, certain antibiotics).
Various biological agents can also cause P. p.Tperr (N.M. Gregg, 1941) and other authors have described malformations associated with diseases of the mother in the early phase of pregnancy viral infections (rubella, measles, mumps). Bacteria and their toxins, apparently, can cause P. R. only by indirect means, causing changes in the mother's body. Teratogenic effects protozoa, in particular toxoplasmosis, controversial.
Trauma to the mother can cause she hormonal shifts, and that ultimately can lead to birth defects. Pathogenetic chain" in this case may be: fear (or long-lasting negative emotions) - > hyperadrenalism > ischemia embryo → malformations.
The same P. R. may be due to both genetic and environmental exposure to the embryo or fetus.
Treatment. Some malformations (atresia, stenosis, fusion, preservation embryonic structures and others) can be effective surgical intervention.
Prevention. Social transformation of society, erasing class, property, racial and religious differences, expand the circle of persons who marry that helps to reduce the number of hereditary diseases, including P. R. important role in the prevention of such diseases can play a medical-genetic consultations. Should be protected from possible teratogenic effects of pregnant women, especially during the first three months of pregnancy, and to ensure proper nutrition. X-ray studies in this period should not be carried out; should avoid medicines that may cause damage to the fetus, and contact with patients, particularly viral infections.
Malformations of separate organs - see articles devoted to these bodies.