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Deficit of antithrombin II


Antithrombin III - natural anticoagulant to which share 75% of all anticoagulating activity of plasma, a glycoprotein with a molecular weight of 58 200 and content in plasma of 125-150 mg/ml fall. Primary structure of antithrombin III consists of 432 amino acids. It blocks prothrombinase - inactivates factors of HIIA, XIa, Xa, IXa, VIIIa, kallikrein and thrombin.

Symptoms of Deficit of antithrombin II:

At the European population the frequency of deficit of antithrombin III makes 1:2000–1:5000. According to some information - 0,3% in population. Among patients with tromboembolic episodes the frequency of deficit of antithrombin III makes 3–8%.

Hereditary deficit of antithrombin III can be 2 types:
The I type - decrease in synthesis of antithrombin III as a result of a gene mutation;
The II type - decrease in functional activity of antithrombin III at its normal products.

Clinical manifestations of hereditary deficit of antithrombin III:
deep vein thrombosis of legs, ileofemoralny fibrinferments (arterial fibrinferments are not characteristic of this pathology);
usual not incubation of pregnancy;
antenatal death of a fruit;
trombofilichesky complications after reception of oral contraceptives.

Functional activity of antithrombin III is determined by ability of a sample of plasma to inhibit the known amount of the thrombin or a factor Ha added to a sample at presence or lack of heparin.

At low activity of antithrombin III the main tests of coagulation are not changed, tests for a fibrinolysis and bleeding time normal, aggregation of thrombocytes within norm. At a geparinoterapiya there is no characteristic adequate increase in AChTV.

Reasons of Deficit of antithrombin II:

In the presence of heparin activity of antithrombin III increases more than by 2000 times. Deficit of antithrombin III is inherited autosomal is prepotent. The majority of carriers of this pathology of a heterozygote, homozygote perish very much early from tromboembolic episodes.

Now about 80 mutations of the gene located on a long limb 1 are described. Occurrence of this pathology strongly varies at different ethnic groups.

Treatment of Deficit of antithrombin II:

Normal the level of antithrombin makes 85–110%. At pregnancy it is a little lowered and makes 75–100%. The lower bound of concentration of antithrombin III is changeable therefore it is necessary to consider not only the level, but also a clinical situation. However at decrease in level of antithrombin III lower than 30% of patients perish from thromboses.

The basis of treatment of deficit of antithrombin III is made by protivotrombotichesky means. In the presence of thrombophilia symptoms treatment needs to be carried out, and it is not discussed. For these purposes use freshly frozen plasma (as an antithrombin III source), low-molecular heparins (эноксапарин sodium, надропарин calcium, далтепарин sodium).

At the low level of antithrombin III heparin sodium is not applied as the geparinorezistentnost and geparinindutsirovanny fibrinferments are possible.

At pregnancy as drugs of the choice serve low-molecular heparins, doses select them individually under control of a gemostaziogramma. As critical recognize II and III trimesters of pregnancy when the coagulative potential of blood grows, and the level of antithrombin III decreases.

Out of pregnancy long reception of antagonists of vitamin K can be recommended to patients (warfarin).

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