Vitamin E deficiency in children

Introduction to vitamin E deficiency in children In recent years, we have focused on the antioxidant properties of vitamin E, which proves that vitamin E can maintain normal reproductive capacity and normal muscle metabolism, maintain central nervous system and retina and other tissues from oxidative damage, maintain vascular system integrity, and cause reproductive disorders due to vitamin E deficiency. The comprehensive symptoms of muscle, liver, bone marrow and brain dysfunction, hemolysis and exudative quality are deficiency of vitamin E (deficiency of vitamin E). basic knowledge The proportion of sickness: 0.01% Susceptible people: children Mode of infection: non-infectious Complications: hemolytic anemia, retinopathy

The cause of vitamin E deficiency in children

(1) Causes of the disease

Vitamin E is common in nature, so it is rare for humans to suffer from deficiency due to insufficient intake of vitamin E. Vitamin E is fat-soluble. When the intestinal absorption of dietary fat in children is hindered, it may cause malabsorption of vitamin E. Then there is a lack and a shortage.

The level of vitamin E in the body is low at birth, because the vitamin E in the newborn is basically obtained from the mother in the second trimester, so the vitamin E storage in the premature infant is lower than that in the normal newborn, and the very low-weight premature infant has fat. Fat-soluble vitamins are poorly absorbed, and vitamin E is more likely to be deficient.

The ratio of vitamin E content to the amount of unsaturated fatty acids in breast milk is suitable. The ratio coefficient is about 0.5. If the content of polyunsaturated fatty acid in formula is too high, when the proportional coefficient is less than 0.4, vitamin E deficiency symptoms appear clinically. Artificially fed children are more prone to vitamin E deficiency.

In cases where bile outflow is impaired or intestinal lipoprotein synthesis is defective, severe vitamin E malabsorption may occur, and children with biliary atresia and cholestasis of liver disease may develop severe vitamin E deficiency during infancy.

In the case of diseases such as thalassemia, sickle cell anemia and glucose-6-phosphate dehydrogenase deficiency, vitamin E may be overutilized due to rupture of red blood cells or lack of other antioxidant pathways, resulting in a deficiency.

If the intake of iron in premature infants is too large, the corresponding requirement for vitamin E should be increased to protect the cell membrane lipids from oxidation. For example, premature use of iron to treat anemia in premature infants destroys the gastrointestinal tract. Vitamin E prevents its absorption and aggravates its lack.

(two) pathogenesis

Vitamin E is soluble in fat and fat solvents. Vitamin E is a general term for all ketone derivatives with alpha-tocopherol bioactivity. It has 1 color full ring, 1 isoprenoid side chain, and -tocopherol. A generic term for a class of compounds that are biologically active. The vitamin E family includes alpha-, beta-, gamma-, and delta-tocopherols, which vary to some extent with the methylation of the color-filled ring, with alpha-tocopherol. The highest activity, various tocopherols can be oxidized to tocopherol free radicals, fertility and fertility hydroquinone, this oxidation can be accelerated by the presence of light, heat, alkali, and some trace elements such as iron and copper, each Tocopherols are stable in acidic environments compared to alkaline environments. Under anaerobic conditions, they are relatively stable to heat and light and alkaline environments. Under aerobic conditions, the esters of free phenolic hydroxyl groups are stable.

Tocopherol acts like an antioxidant, prevents lipid peroxidation of polyunsaturated fatty acids on the cell membrane, protects the body from free radical oxidative damage, and has antioxidant activity against -tocopherol and glutathione containing selenium. Peroxidase is similar, human plasma tocopherol levels change with total plasma lipid levels, which affects the division of plasma and adipose tissue, normal plasma alpha-tocopherol level is 11.6-23.2mol / L, vitamin E mainly Stored in adipose tissue (150 g/g tissue), liver (13 g/g tissue) and muscle (19 g/g tissue), in various tissues and organs, with adrenal gland (132 g/g tissue), pituitary gland (40 g/ g tissue), the highest concentration in testis (40g / g tissue) and platelets (30g / g tissue), high content of alpha-tocopherol in erythrocyte membrane, its concentration is in equilibrium with plasma levels, when plasma vitamin E is lower than At normal levels, erythrocyte membrane rupture is liable to cause hemolysis. Vitamin E is distributed in various lipoproteins in the blood. Children are different from adults. If vitamin E is deficient in the diet, plasma concentration will decrease rapidly.

Vitamin E and selenium, vitamin C, and -carotene have synergistic synergistic effects on antioxidants. Animal experiments have found that vitamin E is essential for maintaining the structure and function of skeletal muscle, myocardium, smooth muscle and peripheral vascular system, and has a function of cell membrane. Close relationship; vitamin E is essential for maintaining normal immune function; vitamin E also inhibits platelet aggregation on the surface of blood vessels and protects vascular endothelium, and is therefore considered to prevent atherosclerosis and cardiovascular disease, vitamin E It can prevent the decomposition of unsaturated fatty acids, lower blood lipids and increase the elasticity of blood vessel walls, which will undoubtedly reduce the incidence of arteriosclerosis and coronary heart disease, thus delaying the aging of the human body. If the diet contains more unsaturated fatty acids, vitamin E The demand for this has increased relatively.

Vitamin E protects the nervous system from oxidative damage. The nervous system in children's development is particularly sensitive to deficiency. Vitamin E deficiency can cause neurological symptoms, mainly affecting the posterior column of the notochord, third and fourth cranial nerve nucleus. The large myelinated axon tube of the peripheral nerve, the elongated nucleus and wedge-shaped leaves of the brainstem, and the muscles and retina.

Vitamin E deficiency can cause reproductive disorders; muscle, liver, bone marrow and brain dysfunction; erythrocyte hemolysis; embryogenesis defects; and exudative quality, which is a capillary osmotic disorder that can produce skeletal muscle atrophy, or accompanied by Myocardial lesions.

Prevention of vitamin E deficiency in children

The demand for vitamin E is different in different physiological periods. The vitamin E requirement during pregnancy is increased to meet the needs of fetal growth and development. Vitamin E can be secreted by milk. The vitamin E content in mature breast milk is about 4mg/L, so the lactating mother should be increased. Intake to compensate for loss in milk. For babies, the recommended intake of vitamin E is based on the amount of breast milk (about 2 mg/d), from the perspective of human aging and oxygen free radical damage. It is necessary to increase the intake of vitamin E.

Pediatric vitamin E deficiency complications Complications hemolytic anemia retinopathy

1. Hemolytic anemia: more common in premature babies.

2. Spinal encephalopathy: mainly found in children, due to the absence of beta lipoproteinemia, chronic cholestatic hepatobiliary disease, celiac disease or genetic abnormalities in vitamin E metabolism and fat malabsorption.

3. Nervous system lesions: retinopathy, ophthalmoplegia, visual impairment, and cognitive and motor dysplasia in young children can be improved with vitamin E.

4. Intracranial and visceral hemorrhage: intraventricular and subependymal hemorrhage, vitamin E supplementation can be improved.

Symptoms of vitamin E deficiency in children Common symptoms Vitamin E deficiency sclerosis ptosis drooping reflexes disappearing weak eye muscle paralysis edema visceral bleeding dysarthria ataxia

1. Changes in the nervous system: progressive neuropathy and retinopathy, spinocerebellar ataxia with deep sacral reflexes disappeared, torso and limbs ataxia, vibration and positional sensation disappeared, ophthalmoplegia, visual field disorder, retinopathy also known as lens Fibrous tissue formation, muscle weakness, ptosis and dysarthria have a negative impact on young children's cognitive ability and motor development.

2. Anemia: Most occur in premature infants with a birth weight of less than l500g. The onset of hemolytic anemia occurs in 4 to 6 weeks. Hemolysis can be stopped after oral administration of vitamin E.

3. Edema: Systemic edema is mainly caused by lower limbs. Premature infants are prone to neonatal scleredema. Most of them can be relieved after 3 days with vitamin E.

4. Intracranial and visceral hemorrhage: lack of vitamin E during pregnancy, the possibility of neonatal intracranial and visceral bleeding is greater, some cases of neonatal intraventricular and subependymal hemorrhage can be improved after taking vitamin E.

Pediatric vitamin E deficiency check

1. In vivo vitamin E nutrition evaluation index

(1) Red blood cell hemolysis test: After the red blood cells are kept with 2% to 2.4% H2O2, the amount of hemoglobin which is hemolyzed is compared with the dissolved solution of distilled water, expressed as a percentage, and its value has a certain relationship with plasma vitamin E level. When vitamin E red blood cells are more sensitive to hydrogen peroxide, an increase in peroxide hemolysis can be observed, and hemolytic anemia can occur.

(2) Low plasma vitamin E levels: plasma tocopherol levels <9.28 mol/L (<4 g/ml), and adult plasma tocopherol levels <11.6 mol/L (<5 g/ml) are lacking.

Oral vitamin E can exist in the blood circulation for 1 to 2 days, so the plasma content can be measured after taking vitamin E for 3 days.

(3) Vitamin E and blood lipid ratio: Because blood lipid level has a direct effect on the plasma concentration of vitamin E, such as infant vitamin E and blood lipid ratio is less than 0.6mg: 1g, it can be considered that vitamin E is deficient, if there is excessive blood lipids, -fertility The phenolic level is increased. When the tocopherol level is <0.7 mg/g plasma fat (<1.6 mol/g), which is equivalent to <11.6 mol/L (<5 g/ml), the blood lipid is normal, which can be diagnosed as lacking.

(4) Determination of vitamin E in red blood cells: The normal average value of vitamin E in red blood cells is 35.42 mol / l ± 2.00 mol / l, plasma is 154.49 mol / l ± 140.76 mol / l, the vitamin E of red blood cells changes less.

2. Have creatine

Vitamin E deficiency can cause excess creatine in the absence of creatine diet and increased plasma creatine phosphokinase levels.

3. Peripheral blood

Hemoglobin is more than 60g ~ 100g / L, reticulocytes are slightly elevated, peripheral blood smears can be seen in the shape of spines and condensed red blood cells, platelets can be increased.

4. Blood biochemical examination

Increased blood bilirubin.

5. Bone marrow

Multinucleated young red blood cells can be seen.

6. Muscle biopsy

Premature infants lacking vitamin E have muscle weakness and necrotic waxy pigmentation in muscle biopsy.

7. Neurophysiological examination

In patients with myeloid encephalopathy, large-caliber myelinated axons can disappear, and the posterior horn of the spinal cord may be degenerated.

Diagnosis and identification of vitamin E deficiency in children

diagnosis

1. History and performance: There are clinical manifestations of premature birth, fat malabsorption and other vitamin E deficiency.

2. Laboratory tests: There is a decrease in the nutritional level of vitamin E.

(1) Plasma vitamin E: Plasma vitamin E concentration is an indicator that directly reflects the adequacy of vitamin E storage in the body. Vitamin E deficiency in vitamin E deficiency is generally considered to be less than 5 mg/L.

(2) Vitamin E and blood lipid ratio: less than 0.6mg: 1g, vitamin E deficiency can be considered.

(3) Anti-peroxide hemolysis test of red blood cells: In the absence of vitamin E in the body, the red blood cells in vitro are more sensitive to H2O2 than hemolysis, and can be used for in vitro test of red blood cells, positive for red blood cell anti-peroxide hemolysis test and hemolytic anemia. It can be considered that there is a lack of vitamin E.

Differential diagnosis

1. Hemolytic anemia: Different from hemolytic anemia caused by other causes, due to hemolytic anemia caused by vitamin E deficiency, plasma vitamin E level is low, and it is improved quickly after treatment with vitamin E.

2. Friedreich Ataxia (FRDA): Vitamin E deficiency syndrome occurs in children with chronic cholestatic hepatic cholangiopathic or cystic fibrosis. The clinical features of progressive neurological damage are similar to those of FRDA, and are easily diagnosed. Misdiagnosed as FRDA, so serum vitamin E level determination and genetic diagnosis help the two identify, FRDA is an autosomal recessive hereditary disease, the disease gene is located in 8q13.1 ~ q13.3.

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