Late-onset vitamin K deficiency in children

Introduction to late-onset vitamin K deficiency in children Children's late vitamin K deficiency (deficiency of vitamin K) is due to vitamin K deficiency caused by coagulopathy, vitamin K deficiency, affecting the activation of certain coagulation factors, coagulation disorders and bleeding. basic knowledge The proportion of illness: the incidence rate is about 0.003% - 0.005% Susceptible people: children Mode of infection: non-infectious Complications: intracranial hemorrhage

The cause of late onset vitamin K deficiency in children

(1) Causes of the disease

Vitamin K, also known as blood coagulation vitamin, is a general term for natural and synthetic vitamin K. Vitamin K1, pork liver, soybeans and green leaf foods such as alfalfa and spinach are abundant in food. Vitamin K2 is synthesized in human intestinal bacteria. Both are fat-soluble, absorbed in the intestine, and need to participate in bile salts and pancreatic enzymes. Synthetic vitamin K has vitamin K3 and vitamin K4, both of which are water-soluble vitamins. Vitamin K is not only the main component of prothrombin. It can also promote the liver to produce prothrombin, which is conducive to hemostasis. The cause of this disease is due to the lack of vitamin K in the body, which makes the synthesis of blood coagulation factors II, VII, IX, X insufficient in the liver, causing bleeding. The causes are as follows: :

1. Maternal deficiency of vitamin K: The mother lacks vitamin K to vitamin K. The placental transport is insufficient, and the vitamin K deficiency in most newborn cord blood is detected by radioimmunoassay.

2. Drug effects during pregnancy: The use of drugs that affect vitamin K metabolism and synthesis during pregnancy causes a deficiency of vitamin K in the neonatal period.

(1) Broad-spectrum antibiotics and sulfonamides: such as long-term application of drugs that inhibit the growth of bacteria in the intestine, such as broad-spectrum antibiotics and sulfonamides that are not easily absorbed in the intestinal tract, can inhibit non-pathogenic bacteria in the intestinal tract and reduce intestinal tract. The synthesis of vitamin K leads to a deficiency of vitamin K.

(2) Vitamins A and D: Excessive intake of vitamins A and D can also inhibit the intestinal synthesis of vitamin K2.

(3) Anticoagulant and anticonvulsant drugs: Oral anticoagulant drugs such as dicoumarin have a structure similar to that of vitamin K, which competes with vitamin K and reduces the synthesis of prothrombin in the liver.

Pregnant women taking anticonvulsant drugs can be transported through the placenta and inhibit the production of vitamin K by anti-coagulant drugs, resulting in a deficiency of vitamin K in newborns.

3. Insufficient intake: Newborns have low milk intake and low vitamin content in breast milk, with an average of 15g/L (60g/L in milk), almost no vitamin K in colostrum, lack of rich vegetables and fruits. Both can cause vitamin K deficiency, and more than 90% of vitamin K deficiency bleeding occurs in breastfed infants.

4. Absorption, dysfunction: Chronic diarrhea, ulcerative colitis, intestinal resection, cystic fibrosis and other diseases caused by intestinal malabsorption in children, can cause vitamin K absorption disorders, as well as biliary obstruction, biliary, bile Lack of sexual disease can also affect the absorption of vitamin K.

5. Synthetic reduction: Intestinal bacteria can synthesize a part of vitamin K, but there is no bacteria in the intestine at birth, vitamin K synthesis is reduced, vitamin K deficiency is significantly reduced after the baby appears in the intestinal colony, long-term application of broad-spectrum antibiotics Inhibition of the growth of normal bacteria in the intestine can lead to vitamin K deficiency.

In addition, liver damage caused by any cause such as neonatal hepatitis, neonatal sepsis and viral infection can affect the synthesis of vitamin K-dependent factors.

(two) pathogenesis

Vitamin K is divided into two categories, one is fat-soluble vitamin K1 (extracted from plants) and K2 (extracted from microorganisms, also made by intestinal bacteria), and the other is water-soluble vitamins, namely K3 and K4. (by artificial synthesis), in which K1 and K2 are the most important, vitamin K controls blood coagulation, and vitamin K is the synthesis of four coagulation proteins (prothrombin, transformation acceleration factor, anti-hemophilia factor and Situ factor) in the liver. An indispensable substance.

Because vitamins K1 and K2 are fat-soluble substances, other fat-soluble vitamins such as A and D can affect their absorption. The structure of oral anticoagulant drugs such as dicoumarin is similar to that of vitamin K, which can compete with vitamin K to reduce thrombin. Originally synthesized in the liver; pregnant women taking anticonvulsant drugs, can be transported through the placenta, and similar anticoagulant drugs to inhibit the production of vitamin K, causing vitamin K deficiency in newborns, liver function in newborns and premature infants is not developed Mature, the synthesis of blood coagulation factors II, VII, IX, X in the liver is insufficient, so that the production of vitamin K-dependent factors is reduced, and intestinal bacteria can synthesize a part of vitamin K, but the newborn has no bacteria in the intestinal tract and vitamin K synthesis is reduced. Lack of vitamin K will lead to abnormal blood coagulation and bleeding.

Prevention of late-onset vitamin K deficiency in children

The synthesis of blood coagulation factors in the liver requires the participation of vitamin K. The vitamin K required by the human body is derived from food on the one hand, and is synthesized by intestinal bacteria on the other hand. If pregnant women and children use anticoagulants due to diseases, a large number of antibiotics, or breastfeeding alone. While mothers eat less foods rich in vitamin K, or twins, premature births and children with chronic hepatobiliary diseases, it is easy to cause vitamin K deficiency, so the main preventive measures are as follows:

1. Prevention of pregnant women, lack of vitamin K in lactating mothers

Neonatal vitamin K deficiency should start from the prevention of pregnant women, can take oral vitamin K 20mg a few weeks before delivery, can prevent low prothrombinemia caused by vitamin K deficiency in newborns, lactating mother should eat more foods rich in vitamin K To increase the vitamin K content in milk, so that infants get more vitamin K from breast milk, such as various dark green leafy vegetables, spinach, cabbage, purple flowers, alfalfa, fruits, soybeans, milk, animal liver, egg yolk, cheese Fish, kelp, seaweed and vegetable oil are rich in vitamin K.

2. Regular vitamin K supplementation after birth

(1) routine intramuscular injection of vitamin K: since the 1961 American Academy of Pediatrics Nutrition Committee proposed that all newborns should be injected intramuscularly with vitamin K1 0.5 to 1 mg after birth as a preventive for neonatal bleeding, vitamin K1 for prevention and cure Neonatal vitamin K deficiency bleeding has been widely used in many countries. Premature infants, low birth weight infants and dystocia have to be intramuscularly injected with vitamin K 1 mg within 6 hours after delivery. Most hospitals in China have also used vitamin K as a postnatal vitamin. Conventionally, the occurrence of vitamin K deficiency natural hemorrhagic disease is effectively prevented.

(2) Oral vitamin K: The Netherlands Cornelissen EA et al. demonstrated that oral vitamin K 1 mg per week can effectively correct vitamin K deficiency within 3 months after birth, and does not cause vitamin K accumulation in the body. The Pediatric Association recommends that newborns born in full-term should be orally or intramuscularly injected with vitamin K 1 mg within 6 hours after birth; China's Lin Liangming is equal to 2002 report, and the 7 provinces of China collaborated on a study of 19,971 live births and found that the birth was given to the baby. After oral administration of vitamin K1 2mg, once every 10 days, served 3 months, a total of 10 times, has a very good effect on the prevention of vitamin K deficiency bleeding.

3. Actively prevent vitamin K deficiency

Newborns with risk of delayed bleeding due to fat malabsorption, pregnant women with children with broad-spectrum antibiotics, twins, premature infants, children with hepatitis, congenital biliary atresia should be given prophylactically Vitamin K, daily oral vitamin K 1mg or monthly intramuscular injection of vitamin K 1 time to prevent vitamin K deficiency hemorrhagic disease.

Complications of late-onset vitamin K deficiency in children Complications intracranial hemorrhage

Late onset vitamin K deficiency in children can be complicated: intracranial hemorrhage, pulmonary hemorrhage and hemorrhagic anemia, severe intracranial hemorrhage often left behind.

1. Intracranial hemorrhage (intracerebral hemorrhage, abbreviation: ICH) refers to the rupture of blood vessels in the brain, causing hemorrhage. Therefore, the brain cells that obtain blood from the blood vessels are destroyed, and the blood vessels are forced to block the surrounding nerve tissue.

2. Hemorrhagic anemia:

1 acute hemorrhagic anemia, due to trauma or surgery caused by internal organs (such as liver, spleen, luminal artery and vena cava, etc.) and extracorporeal vascular rupture caused by massive bleeding, so that the body's blood solubility suddenly decreased.

2 chronic hemorrhagic anemia, mainly due to chronic stomach, intestinal inflammation, lung, kidney, bladder, uterine bleeding inflammation, resulting in long-term repeated bleeding. In addition, canine hookworm infection can also cause chronic hemorrhagic anemia.

Symptoms of late-onset vitamin K deficiency in children Common symptoms Irritating skin purpura bleeding tendency diarrhea Respiratory irregular intracranial hypertension full convulsions blood in the stool intracranial hemorrhage

It occurs more than 1 month after birth, and more than 90% of them are found in breast-fed infants. For example, diarrhea, broad-spectrum antibiotics, hepatobiliary diseases and long-term fasting are more likely to occur.

1. The onset of illness: The condition is serious, and it is more common in breastfed children 4 to 8 weeks after birth.

2. Intracranial hemorrhage: most of the first manifestations of acute or subacute intracranial hemorrhage, subarachnoid, subdural, epidural hemorrhage is more common, ventricle, parenchymal hemorrhage is rare, clinically have serious central nervous system function Abnormalities and intracranial hypertension manifested as irritability, loud screaming, frequent vomiting, repeated convulsions, severe coma in children, irregular breathing, severe cerebral palsy, physical examination revealed full sputum, cranial suture Widening, Moro reflection, foraging reflection disappears.

3. Severe bleeding tendency: visible skin purpura, mucosal bleeding, bleeding at the injection site, often hematemesis, blood in the stool.

4. Anemia: There may be hemorrhagic anemia at the same time.

5. Laboratory examination: The clotting time and prothrombin time were significantly prolonged.

Delayed neonatal hemorrhagic disease, most of the first manifestations of intracranial hemorrhage, sudden onset, no obvious symptoms of infection, anemia develops rapidly and severely.

Examination of late-onset vitamin K deficiency in children

1. Coagulation function test: Platelet, bleeding time is normal, prothrombin time is prolonged, most of them prolonged to more than 2 times of normal control, mild vitamin K deficiency only prolonged prothrombin time, clinical no bleeding tendency, partial coagulation activity of clay The enzyme time is prolonged, and the activities of coagulation factors II, VII, IX, and X factors are significantly reduced. The factor VII is first reduced to a minimum. When the factor VII is decreased, the prothrombin level is decreased, but it is slow. The IX factor is different. To a lesser extent, prothrombin testing is a reliable evidence of vitamin K deficiency.

2. Vitamin K test: The detection of vitamin K is feasible when necessary.

3. Cerebrospinal fluid examination: The cerebrospinal fluid of children with intracranial hemorrhage presents uniform blood and shrinking red blood cells, but the cerebrospinal fluid examination can not completely rule out intracranial hemorrhage, and those who are critically ill should not carry out this examination.

If necessary, B-ultrasound, CT and MRI examinations, such as suspected intracranial hemorrhage, B-ultrasound, CT or MRI examination is helpful for diagnosis, not only can understand the bleeding, determine the location of bleeding, range, but also follow-up efficacy, Prognosis judgment.

Diagnosis and differential diagnosis of late-onset vitamin K deficiency in children

diagnosis

Diagnosis can be made based on medical history, symptoms, signs and clinical manifestations, and laboratory findings.

1. History: Detailed medical history, understanding the feeding situation of children and the addition of complementary foods, more common in breast-fed infants, infants within 3 months after birth, have not received vitamin K prevention, or have persistent diarrhea, long-term use History of broad-spectrum antibiotics.

2. Clinical features: rapid onset, spontaneous bleeding or puncture site bleeding is not only the main clinical features; laboratory examination is mainly prolonged prothrombin time, platelets, bleeding time is normal; vitamin K treatment is good, hours or The bleeding tendency improved significantly after 24 hours.

Differential diagnosis

Different from congenital clotting factor deficiency and intracranial infectious diseases, late neonatal hemorrhagic disease, most of the first manifestations of intracranial hemorrhage, sudden onset, but no obvious symptoms of infection, anemia develops rapidly and severely, plus After the administration of vitamin K, the condition improved, so it can be differentiated from intracranial infection.

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