Vitamin K deficiency

Introduction to vitamin K deficiency Vitamin K is an essential fat-soluble vitamin that plays an important role in the blood coagulation process. Vitamin K is high in green leafy vegetables and various edible oils such as soybean, cottonseed, rapeseed and olive oil. Vitamin K deficiency can occur at any age, but babies are the most common. basic knowledge The proportion of sickness: 0.01% Susceptible people: more common children Mode of infection: non-infectious Complications: intracranial hemorrhage

Vitamin K deficiency disease etiology

Causes

Absorption barrier

(1) Bile salt deficiency: such as common bile duct obstruction, biliary fistula, bile salt deficiency caused by postoperative bile drainage, or long-term use of mineral oil lubricants, so that fat-soluble vitamin K absorption disorder.

(2) various intestinal lesions: malabsorption syndrome, after gastrointestinal resection and so on.

(3) Long-term use of broad-spectrum antibiotics to inhibit intestinal bacterial growth and reduce intestinal vitamin K2 synthesis.

Use barrier

Severe liver dysfunction, oral anticoagulants such as warfarin (Warfarin), acenocoumarin (Acenocumarol) and dicoumarin (Dicoumarol) and other chemical structures and vitamin K analogues, can inhibit the participation of vitamin K Synthetic activation of coagulation factors, vitamin K deficiency or oral anticoagulant can cause the formation of blood-derived vitamin K deficiency protein (PIVKA-II), PIVKA-II glutamic acid residues R-carboxylated, can not bind to Ca2, can not adhere to phospholipids, can not activate, no coagulation function.

Active transport absorption

Vitamin K2 is passively diffused and absorbed in the terminal ileum and colon. It requires bile, pancreatic juice, and is combined with chylomicrons. It is transported by the lymphatic system to the whole body and stored in the liver, adrenal gland, lung, bone marrow, kidney and other organs. Excretion from the urine in the form of glucuronic acid derivatives, affecting intestinal absorption factors, liquid paraffin, other lipid solvents, laxatives can significantly reduce the absorption of vitamin K, long-term diarrhea fat absorption disorders, or patients with bile duct obstruction , often lead to vitamin K deficiency; long-term antibiotic treatment inhibits the synthesis of vitamin K in the intestinal tract, can also cause vitamin K deficiency, vitamin K complex activity is easily destroyed by ultraviolet light and alkali.

Vitamin K is an important coenzyme for vitamin K-dependent coagulation factors (II, VII, IX, X), -carboxylation of plasma coagulation inhibitor (protein C, protein S) glutamate residue, and when vitamin K is deficient, the above-mentioned coagulation factor The synthesis, activation is significantly inhibited, causing various bleeding manifestations, vitamin K-assisted glutamate residue -carboxylation also occurs in bone, tooth, kidney, skin, liver and breast tissue protein molecules, in the bone It is to regulate osteocalcin-osteocalcin (osteo-calcin) deposited in bone matrix, and may be involved in renal tubular reabsorption of calcium. In 1989, the American Academy of Sciences recommended daily dietary supply of vitamin K, normal adult male daily. 70 to 80 g, 60 to 65 g per day for adult women, and the amount of vitamin K required for humans is 0.5 to 1.0 g/kg per day.

Vitamin K deficiency prevention

It is recommended to routinely use vitamin K1 0.5~1mg for neonates to prevent hypoprothrombinemia and reduce the incidence of intracranial hemorrhage caused by trauma. It can also be used prophylactically when considering surgery. Give the mother a prophylactic dose (2~5mg/d, oral) of vitamin K1 for the first week, or give vitamin K1 solution (2~5mg, intramuscular injection) 6 to 24 hours before delivery. Pregnancy with anticonvulsant medication Women should take 20 mg of vitamin K1 daily to prevent fetal bleeding 2 weeks before delivery. Low levels of green leaf in breast milk are not due to insufficient intake and cannot be stored by fresh green leafy vegetables that are eaten every day.

Vitamin K deficiency complications Complications intracranial hemorrhage

Typical neonatal vitamin K deficiency, more than 2 to 5 days after onset, gastrointestinal bleeding, may be associated with skin bleeding, umbilical cord bleeding, etc., delayed vitamin K deficiency bleeding in infants more common 2 weeks after birth ~3 months breast-fed infants, clinical features of acute onset, hemorrhagic symptoms, often intracranial hemorrhage caused by increased intracranial pressure and neurological symptoms, critically ill.

Vitamin K deficiency symptoms common symptoms fat-soluble vitamin deficiency intracranial pressure increased intracranial hemorrhoids gum bleeding meningeal irritation signs bleeding tendency vitamin K deficiency horn bow reverse gastrointestinal bleeding hemorrhage

Mainly manifested as bleeding symptoms of different severity, common nosebleeds, gingival bleeding, subcutaneous bruising, black feces, menorrhagia, hemorrhoids hemorrhage, wound and postoperative bleeding, deep tissue hematoma and less joint blood See, even if intracranial hemorrhage is life-threatening, the bleeding symptoms caused by vitamin K deficiency in newborns are often sudden and without warning.

1. Vitamin K deficiency: mild vitamin K deficiency, no bleeding in the clinic, can only be determined by means of prothrombin time to determine the diagnosis, when the concentration is reduced to 35% to 40% of normal, in the damage Wounds, ulcers, pinholes and brushing often show oozing, surgery, anesthesia, blood loss or other causes of liver damage, prothrombin concentration decreased more, bleeding increased, if the concentration dropped to normal 15% ~ 20 Below %, spontaneous bleeding may occur, such as subcutaneous hemorrhage, or in the pressure, such as the back, buttocks, thighs, and impact or puncture sites, cyanosis or hematoma of varying sizes may occur, often with bleeding of the nose and gums. Or even bloody, black feces, etc., anal fistula often bleeding, fewer cases of hematuria, a large number of blood loss or intracranial hemorrhage can be life-threatening.

2. Neonatal hemorrhagic disease: one of the special manifestations of this disease, there is not enough bacteria in the intestine after birth to synthesize vitamin K, and there is very little vitamin K in human milk, so the blood prothrombin concentration continues to decline, to the second ~ The lowest level in 3 days (about 10% to 40% of normal), after which the concentration of prothrombin gradually rises and recovers until the 7th to 8th day. There may be gastrointestinal bleeding within one week of birth, followed by other bleeding tendency. If there is intracranial hemorrhage, it can cause meningeal irritation and increased intracranial pressure syndrome, vomiting, angulation and so on.

Vitamin K deficiency check

1. The most sensitive indicator of vitamin K deficiency is the presence of de-gamma-carboxy-prothrombin (DCP) in plasma. DCP, also known as PIVKA (a protein that is induced by vitamin K deficiency or antagonism), can be assayed using suitable antibodies. None in healthy people's plasma.

2. Coagulation factor II, VII, IX, X decreased, showing prolonged prothrombin time, or prolonged partial thromboplastin time.

3. Prothrombin correction test can identify factor V and fibrinogen deficiency, plasma PIVKA-II increased.

4. When the condition is serious, the clotting time and plasma recalcification time are also prolonged. After the vitamin K supplementation, the above determination can be restored to normal.

According to the clinical manifestations, ECG and B-ultrasound can be performed.

Diagnosis and identification of vitamin K deficiency

According to symptoms, signs and medical history, the possibility of vitamin K deficiency can be diagnosed. When PT and PTT are prolonged, the diagnosis can be confirmed. The therapeutic test can help to exclude liver patients.

Other diseases that need to be identified with it, such as scurvy, allergic purpura, leukemia, thrombocytopenia, are not characterized by low prothrombinemia.

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