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November 06, 2016 00:02

Vitamin K ( phylloquinone ) : vitamin K deficiency

Vitamin K (phylloquinone) - it is the food of vitamin K. The fat food increases its absorption.The formula for the infant formula is administered supplements of vitamin K. Vitamin K refers to a group of compounds (menaquinone), synthesized by intestinal bacteria;synthesized amount does not satisfy the needs for vitamin C.

Vitamin K controls the formation of blood coagulation factors II (prothrombin), VII, IX and X in the liver.Other vitamin K-dependent coagulation factors - proteins C, S and Z;Proteins C and S - anticoagulants.Metabolic transformation contribute to the preservation of vitamin K;as vitamin K participated in the formation of blood coagulation factors, the reaction product of vitamin K epoxide, is converted into an enzymatically active form of vitamin K hydroquinone

To detect the action of vitamin K-dependent proteins require Ca.Vitamin K-dependent proteins, osteocalcin and matrix block comprising y-carboxyglutamic protein, play an important role in bone and other tissues.

Hypovitaminosis vitamin K

Vitamin K deficiency is a consequence of the extremely inadequate dietary intake, malabsorption of lipids or the use of anticoagulants coumarin group.Deficiency is particularly common in children who are breastfed.Hypovitaminosis It contributes to poor blood clotting.The diagnosis can be suspected on the basis of standard tests of blood clotting and to confirm the presence of the effect of vitamin K. Treatment consists of administration of vitamin K orally.In the case where the cause is deficiency of lipid malabsorption, or high risk of bleeding, vitamin K is administered parenterally.

Vitamin K deficiency reduces the levels of prothrombin and other vitamin K-dependent clotting factors, causing coagulation disorders, and potentially bleeding.

Causes of vitamin K deficiency

Worldwide vitamin K deficiency can cause growth of infant morbidity and mortality.Deficiency of vitamin K causes hemorrhagic disease of the newborn, which usually manifests itself at 1-7 days after birth.Such newborn birth trauma can cause intracranial hemorrhage and bleeding.Infants tend to deficiency of vitamin K because:

  1. relatively poorly transmits placenta lipids and vitamin K;
  2. prothrombin synthesis in the liver is still immature imperfect;
  3. in breast milk is low in vitamin K - about 2.5 mg / l (cow's milk contains 5000 mg / l) and
  4. sterile intestines of newborns during the first few days of life.

Late hemorrhagic disease (after 3-8 weeks after birth) is usually associated with breastfeeding, malabsorption, or liver disease.If the mother is taking anticonvulsants phenytoin group, coumarin anticoagulants group or cephalosporin antibiotics, the risk of both types of hemorrhagic disease increases.

In healthy adults, dietary vitamin K deficiency is rare, because vitamin K is widely distributed in green vegetables and intact intestinal bacteria synthesize menaquinone.Blockage of the biliary tract, malabsorption, cystic fibrosis, and resection of the small intestine contribute to deficiency of vitamin K. Anticoagulants

group coumarin interfere with the synthesis of vitamin K-dependent clotting factors (II, VII, IX and X) in the liver.Certain antibiotics (especially some cephalosporins and other broad-spectrum antibiotics), salicylates, megadoses of vitamin E and liver failure increase the risk of bleeding in patients with a deficiency of vitamin K.

Symptoms of vitamin K deficiency bleeding

- is the most common manifestation.Characterized by easy bruising and bleeding of mucous membranes (especially epistaxis, gastrointestinal bleeding, menorrhagia, and hematuria).Blood may leak from cuts or puncture site.

Infants hemorrhagic disease of the newborn and late hemorrhagic disease can lead to skin, gastrointestinal, intrathoracic, and in the worst cases intracerebral hemorrhage.When obstructive jaundice bleeding - if it happens - usually begins after 4-5 days.Bleeding may start as slow seepage from hirugicheskoy wounds, gums, nose, gastrointestinal mucosa or massive gastrointestinal.

diagnosis of vitamin K deficiency

Vitamin K deficiency or antagonism (caused by taking coumarin anticoagulants) may be suspected in the case where the at-risk patients have abnormal bleeding.The research phase of blood clotting can pre-confirm the diagnosis.Prothrombin time (PT), currently - MHO (international normalized ratio) is extended, but the partial thromboplastin time (PTT), thrombin time, platelet count, bleeding time and fibrinogen levels of fibrin degradation products and D-dimer in the norm.If administered intravenously 1 mg phytonadione (vitamin K analog name) PX is significantly reduced for 2-6 hours, it is unlikely to cause liver disease and thus confirms the diagnosis of vitamin K deficiency Some centers may identify a deficiency of vitamin Kprecisely measuring the level of the vitamin in the blood plasma.Plasma levels of vitamin K varies from 0.2 to 1.0 ng / ml in healthy people consuming adequate amounts of vitamin K (50-150 mg / day).Knowing the amount of intake of vitamin K may help to interpret its plasma levels;recent consumption affects plasma levels, but not in the tissues.In

currently under study are more sensitive indicators of the status of vitamin K - PIVKA {Protein Induced in Vitamin K Absence or Antagonism - protein induced in the absence or antagonism of vitamin K) or immature (non-carboxylated) osteocalcin.

prevention of vitamin K deficiency

recommended intramuscular phytonadione at a dose of 0.5-1 mg of all newborns within the first hour after birth to reduce the degree of intracranial hemorrhage due to birth trauma.This method is also used prophylactically prior to surgical interventions.Some clinicians recommend that pregnant women taking anticonvulsants, and phytonadione taken at a dose of 10 mg orally 1 time a day for 1 month or 20 mg orally 1 time a day for 2 weeks before delivery.Due to the low levels of vitamin K in breast milk of his mother can be increased, recommending to take food up to 5 mg / day phylloquinone.

treatment of vitamin K deficiency

Every time, if possible, phytonadione need to be given orally or subcutaneously.The usual dose for adults - 5-20 mg.(Rarely, even if phytonadione properly diluted and administered slowly replaced with intravenous administration can lead to anaphylactic shock or anaphylactic reactions.) MHO usually decreases for 6-12 hours.The dose may be repeated after 6-8 hours, if there was not a sufficient reduction MHO.Phytonadione at a dose of 2.5-10 mg orally indicated for correction (non-emergency) elongated MHO in patients taking anticoagulants.Correction usually occurs within 6-8 hours.When desired, only partial correction of MHO (for example, when MHO should remain somewhat elevated because of the artificial heart valve), you can assign a lower dose (1-2.5 mg) phytonadione.

babies who because of the deficit observed bleeding phytonadione administered at a dose of 1 mg once daily by subcutaneous or intramuscular injection for their correction.The dose is repeated if the MHO remains elevated.Dosages may be higher if the mother is taking oral anticoagulants.

Hypervitaminosis (intoxication) vitamin K

Vitamin K1 (phylloquinone) is non-toxic when taken internally, even in large quantities.However, menadione, a synthetic water-soluble precursor of vitamin K, can cause intoxication and should not be used for the treatment of deficiency of vitamin K.