Vitamin B6 Dependence Syndrome

Introduction to Vitamin B6 Dependence Syndrome Vitamin B6 includes six interpretable pyridoxines, pyridoxamine, pyridoxal and their respective 5-phosphates. Pyridoxal 5-phosphate is an important part of this group, and it is involved in the metabolism of amino acids, proteins, lipids, nucleic acids and glycogen in the body as a coenzyme of the enzyme system in decarboxylation and transamination. If it is lacking, it can cause convulsions and peripheral nerve diseases. Therefore, vitamin B6 deficiency can cause biochemical and physiological abnormalities. Vitamin B6 dependence syndrome (vitamin B6dependencysyndrome) is a structural and functional defect of an innate metabolic enzyme, kynurenine, whose activity is only 1% of normal. At this time, the vitamin B6 requirement is 5 to 10 times that required for normal children. Sometimes, because the pregnant mother takes a large dose of vitamin B6 during the pregnancy reaction period, the baby still needs to rely on a larger amount of vitamin B6 after birth. basic knowledge The proportion of illness: 0.013% Susceptible people: children Mode of infection: non-infectious Complications: peripheral neuritis dermatitis anemia depression depression stomatitis

The cause of vitamin B6 dependence syndrome

Genetic factors (90%):

Vitamin B6 dependency syndrome is a structural and functional defect of the metabolic enzyme-kynudinase. Its activity is only 1% of normal. At this time, the vitamin B6 requirement is 5-10 times that required for normal children. Sometimes, because pregnant mothers take large doses of vitamin B6 during the pregnancy reaction period, the baby still needs to rely on a larger amount of vitamin B6 after birth.

Other reasons (10%):

Vitamin B6 consists of six interpretable pyridoxines, pyridoxamine, pyridoxal and their respective 5-phosphates. Pyridoxal 5-phosphate is in this group. An important part, in the decarboxylation and aminotransferase, as a coenzyme of the enzyme system, participates in the metabolism of amino acids, proteins, lipids, nucleic acids and glycogen in the body. If it lacks convulsions and peripheral nerve diseases, vitamin B6 deficiency can cause biochemistry. And physiological abnormalities.

Vitamin B6 dependence syndrome prevention

Advocating "balanced diet" and correcting "biased food, picky eaters", we advocate a balanced diet, that is, the variety of foods should be diversified, so that various nutrients can complement each other, children with partial eclipse or picky eating habits, not only weight, height, chest circumference, etc. The developmental indicators are not up to standard, and the lack of nutrients is very prone to occur. There are also many opportunities to infect various diseases. The amount of normal vitamin B6 is 0.3 to 0.5 mg/d for infants and 0.5 to 2 mg/d for children. When eating high-protein foods, vitamin B6 should be added. In addition, the cooking method should be paid attention to. The heating time should not be too long to avoid repeated boiling to prevent the effective value of vitamin B6. When repeated convulsions in an infancy, anemia, chronic diarrhea should be To the hospital for hospital diagnosis, the diagnosis should be treated as soon as possible, supplement vitamin B6, reduce the occurrence of convulsions, reduce the impact on children's intelligence, tuberculosis patients with isoniazid treatment, injection of nervous system symptoms, such as abnormalities should reduce isoniazid It is best to add vitamin B6 at the same time.

Vitamin B6 dependent syndrome complications Complications peripheral neuritis dermatitis anemia depression stomatitis

In infancy, the main symptoms of pyridoxine deficiency are systemic convulsions, and other manifestations of peripheral neuritis, dermatitis, and anemia. Infants less than 6 months after birth, such as lack of vitamin B6 in feeding food, can show nervousness, increased excitement and frequent systemic convulsions, leading to depression, dull sleep mental retardation, vibration and positional consciousness disappear. At the same time, there are often gastrointestinal symptoms. When treating tuberculosis with isoniazid, peripheral neurodegenerative diseases (more common in adults), as well as inflammation of the skin and mucous membranes, such as seborrheic and desquamative dermatitis, stomatitis, glossitis, ophthalmia, etc., may occur.

Symptoms of vitamin B6-dependent syndrome Common symptoms Gastrointestinal symptoms Tongue convulsions Convulsions withdrawal response Diarrhea Depression Sleepiness infants need a larger amount... Peripheral neuritis

In case of unexplained convulsions in an infancy, anemia or chronic diarrhea, if hypocalcemia, hypoglycemia, hyponatremia and infectious diseases have been ruled out, vitamin B6 deficiency or dependence disease should be considered, and the injection of vitamin B6100mg can be stopped. As a diagnostic basis, the tryptophan load test can be clearly diagnosed, the method is as follows: oral 50 ~ 100mg / kg tryptophan solution (each total does not exceed 2g), a large amount of jasmonic acid can appear in the urine of children, normal people This phenomenon is not present, but in patients with vitamin B6 dependence, this test may be negative, serum and red blood cell trough-grass transaminase decreased, and EEG has a waveform with abnormal frequency and amplitude change.

In infancy, the main symptoms of pyridoxine deficiency are systemic convulsions, other manifestations of peripheral neuritis, dermatitis and anemia. Infants less than 6 months after birth, such as lack of vitamin B6 in feeding food, can show nervousness, increased excitement And frequent systemic convulsions, leading to depression, dull sleep mental retardation, vibration and positional sensation disappear, and often have gastrointestinal symptoms, when using isoniazid to treat tuberculosis, peripheral neurodegenerative diseases can occur (more common in adults), And inflammation of the skin and mucous membranes, such as seborrheic and desquamative dermatitis, stomatitis, glossitis, ophthalmia, etc.

Vitamin B6-dependent syndrome is mostly a hereditary disorder.

Examination of vitamin B6-dependent syndrome

(1) Tryptophan test After taking oral tryptophan in the sick child, urine is taken to detect the discharge of jaundice, which is a positive reaction if it is lower than normal.

(2) MeHenry's test gives blood to the sick child after oral administration or injection of alanine. The concentration of urea is significantly higher than that of normal.

The above two positive tests have only a reference value for diagnosis.

Diagnosis and identification of vitamin B6 dependence syndrome

Laboratory diagnosis

Blood: The number of white blood cells is significantly increased, up to 40×109/L, and neutrophils are above 80%-90%.

Suspected of the brain should be done lumbar puncture examination, cerebrospinal fluid (CS) pressure often increased up to 1.96kPa; typical cases of CS appearance turbidity such as rice soup or even pus; increased white blood cell count, up to hundreds of millions per liter, to polymorphism Nuclear cells are dominant; protein is significantly increased, up to 1-5g / L; sugar is often less than 2.22mmol / L, chloride is also slightly reduced, CS smear can find Gram-negative diplococcus in neutrophils .

Separation from the patient's CS or acute phase of blood to the meninges.

A brain-brain-specific polysaccharide antigen is detected from the acute phase of the patient's serum or urine or CS.

The serum antibody titer of the recovery period was 4 or more times higher than that of the acute phase.

DNA-specific fragments of the brain in the acute phase of the patient or CS in the CS were detected by PCR.

Differential diagnosis

Sudden chills, high fever, nausea, vomiting, runny nose, stuffy nose, sore throat, body aches, headaches worse.

His face is pale, his limbs are cold, his skin is faint and there are scattered small bleeding spots, his lips and fingertips are bruising, and his lips are herpes simplex.

Irritable, embarrassed, comatose or horrified.

Skin, mucous membrane defects are typical or fused into ecchymoses, blood pressure drops significantly, pulse speed is fine, and pulse pressure difference is reduced.

The neck is stiff, the horn is reversed, the Klinefelter sign and the Brinell sign are positive.

The pupils are of different sizes, the edges are not uniform, the response to light is slow, and the eyeballs often gaze.

Breathing slowness and unevenness or apnea.

The incidence of young children is atypical, common high fever, vomiting, lethargy, but also more extreme anxiety and convulsions, refusal, screaming, diarrhea, cough, binocular gaze, neck stiffness and Brine's sign positive, other meningeal irritation may be missing The anterior iliac crest is often seen in the bulge, and the vomiting is frequent and the dehydration can also occur.

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