What Is Vitamin A Toxicity?

Vitamin A toxicity: A poisoning syndrome caused by excessive intake of vitamin A in the body. According to research, infants and young children who take vitamin A at a dose of more than 300,000 IU (containing vitamin A850 IU per gram of common cod liver oil; vitamin A5-65,000 IU per gram of concentrated cod liver oil) can cause acute poisoning. Chronic poisoning can occur if you take 50,000 to 100,000 international units daily for about 6 months. In addition, the sensitivity and tolerance of children to vitamin A may vary greatly from individual to individual. Some children may also experience mild symptoms of poisoning when taking cod liver oil that does not exceed the above range.

Vitamin A poisoning

Vitamin A toxicity: A poisoning syndrome caused by excessive intake of vitamin A in the human body. According to research, infants and young children who take vitamin A at a dose of more than 300,000 IU (containing vitamin A850 IU per gram of common cod liver oil; vitamin A5-65,000 IU per gram of concentrated cod liver oil) can cause acute poisoning. Chronic poisoning can occur if you take 50,000 to 100,000 international units daily for about 6 months. In addition, the sensitivity and tolerance of children to vitamin A may vary greatly from individual to individual. Some children may also experience mild symptoms of poisoning when taking cod liver oil that does not exceed the above range.

Introduction to Vitamin A Poisoning

Disease Name: Vitamin A Poisoning

Vulnerable groups: infants, children, adolescents

Location: Whole body

Symptoms and signs: edema, hair loss, short stature, headache

Physical examination: Cerebrospinal fluid pressure

The so-called vitamin poisoning. It is a toxic condition that occurs after taking too much vitamins. It was first reported in the 1960s. Arctic explorers developed headaches, vomiting, and drowsiness within hours of eating polar bear livers. 90 to 95% of vitamin A in humans and animals was stored in the liver.

Children's diet prevents vitamin A poisoning

Due to the abuse of vitamin A concentrate in China, the number of people who have symptoms of poisoning is increasing, mainly due to the lack of parents' reasonable knowledge of vitamin A. They believe that the higher the dosage, the better the medical staff and the lack of vigilance. It has been thought that children and athletes need a lot of vitamins. In recent years, it has been proposed that the use of high-dose vitamins can prevent cancer, can treat hyperlipidemia and arteriosclerosis, etc., and the so-called "high-dose vitamin therapy" has appeared. This increases people's chances of taking excessive vitamins, and excessive vitamin poisoning often occurs.

In order to reduce the harmfulness of excessive vitamins to the human body, the poisoning doses and symptoms of various vitamins are briefly described to attract people's attention. The symptoms of vitamin poisoning vary according to the vitamins taken. The symptoms of acute poisoning of excessive vitamin A are mainly drowsiness, headache, vomiting, and papillary edema. The baby has a swollen forehead.

The symptoms of chronic poisoning are mainly dry, rough, fish-like skin, hair loss, chapped lips, itching, tongue pain, clubbing fingers, bone hypertrophy, nystagmus, fragile nails, high calcium; blood, hepatosplenomegaly, etc. , Even increased intracranial pressure and low fever. Children also have anorexia, anal itching, no weight gain, severe irritability, bone swelling, pain, and restricted exercise. Large doses of vitamin A can also be teratogenic. Scientists point out that taking 25,000-50,000 international units (IU) per day for more than eight consecutive months may cause poisoning. Adults take 150,000 IU of poisoning at one time. Therefore, when using large doses of vitamin A to treat children with learning disabilities and prevent cancer, careful attention should be paid to avoid excessive poisoning.

Pathogenesis of vitamin A poisoning

Vitamin A excess can reduce the stability of cell membranes and lysosomal membranes, damage cell membranes, release enzymes, and cause liver, brain, skin, and bone tissue damage.

Causes of vitamin A poisoning

There are two types of cod liver oil preparations: concentrated cod liver oil drops and pills, the ingredients of which are vitamin D and vitamin A. Both of these vitamins are important for children in growth and development. Vitamin D is mainly used to prevent rickets, and vitamin A plays an important role in ensuring the development and function of children's eyes, skin and other organs.

However, there is a problem that is often overlooked. In these cod liver oil preparations, the content of vitamin A is much higher than the content of vitamin D. If this kind of preparation is used for children for a long time, or a larger dose is used to treat rickets, it is easy to cause a large amount of vitamin A to accumulate in the body and cause toxicity. A large intake of pure vitamin A preparation at one time can cause acute poisoning. It has been reported that giving 300,000 IU of vitamin A at one time can cause symptoms of poisoning within a few days; if excessive intake of vitamin A over a long period of time, chronic poisoning can occur, taking 25,000 to 50 thousand IU daily for 3 consecutive months Can cause chronic poisoning. Polar bear liver contains the largest vitamin A, which can cause vitamin A poisoning after eating. Some people report acute vitamin A poisoning caused by ingestion of a complete dog liver within 1 to 2 days in adults, and children's daily intake of some chicken livers causes chronic vitamin A poisoning for several months. In addition, some people have suggested that poisoning is related to physical specificity, that is, vitamin A absorption, utilization, excretion, and intrahepatic storage, there are individual differences.

Due to the lack of parents' knowledge on the reasonable application of vitamin A, long-term or short-term large doses of excessive cod liver oil were given to children, and medical staff also lacked vigilance against the disease. Due to individual differences and the amount of vitamin A stored in the liver, the doses that cause vitamin A poisoning can vary widely. It has been reported that an adult dose of more than 500,000-1 million IU and a child of more than 300,000 IU can be ill. Some children also take 10,000 to 20,000 IU daily, and symptoms may occur for several months.

People susceptible to vitamin A poisoning

People susceptible to vitamin A poisoning are mainly caused by the opportunity to regularly drink a lot of medicines or foods rich in vitamin A. Since this analysis, it is necessary to first understand the main role of VA, and it is easier to judge the vulnerable groups of vitamin A poisoning based on the symptoms of VA deficiency.

1. Vitamin A can mainly participate in the synthesis and regeneration of retinal rhodopsin, maintain normal dark adaptation, and maintain normal vision. Therefore, people with such conditions should pay attention to vitamin A poisoning when taking drugs.

2. Vitamin A can participate in the biosynthesis of glycoproteins in epithelial cells and mucosal cells, and maintain the normal structure and function of epithelial cells. Therefore, people with such conditions should pay attention to vitamin A poisoning when taking drugs.

3. Vitamin A can promote protein biosynthesis and osteocyte differentiation, and promote body growth and bone development. People with these conditions should be careful of vitamin A poisoning when taking the drug.

4. Immunoglobulin is also a glycoprotein, and its synthesis is related to VA, so it has the effect of increasing the body's anti-infection. For people with such conditions, pay attention to vitamin A poisoning when taking the drug.

Vegetables high in vitamin A

5. Vitamin A can promote the normal differentiation of epithelial cells and control their malignant transformation so as to have anti-cancer effect. People with these conditions should be careful of vitamin A poisoning when taking the drug.

Vitamin A poisoning signs

Acute poisoning: children may accidentally consume a large amount of vitamin A at a dose (300,000 IU), which will cause symptoms of poisoning within a few days; adults eat polar bear or cod liver, or take vitamin A> 500,000 IU once 6-8h. Or symptoms of acute poisoning occurred within 1-2 days. There are mainly manifestations of increased intracranial pressure such as headache, vomiting, irritability, and lethargy. In children, there are still appetite, anterior condylar bulge, enlarged head circumference, dehiscence of bone suture, and optic papillary edema, which are caused by excessive secretion of cerebrospinal fluid or malabsorption.

Chronic poisoning: It is mostly caused by long-term excessive intake. Adults consume 80,000 to 100,000 IU of vitamin A daily for half a year, or 30,000 to 40,000 IU daily, for more than a few years; children consume 20,000 daily Above IU, for 6 consecutive months, can cause chronic poisoning. The symptoms of poisoning are not directly proportional to the intake. The clinical manifestations are diverse. Children are irritable, irritable, stupefied, bone pain in the limbs, swelling and tenderness of the soft tissue, swelling and tenderness in the back of the pillow, which can be mistaken for softening of the skull, the skull The prominent protrusions on both sides of the temporal can be mistaken for rickets. At the same time, headache, vomiting, anterior crest widening and bulging, and increased head circumference were observed. The skin is rough, itchy and desquamated, the hair is dry and easy to fall off, and the lips are ruptured and easy to bleed. Adults often show loss of appetite, weight loss, dry skin and desquamation, hepatosplenomegaly, and occasionally can cause gum bleeding, nosebleeds, and anemia. Early oral administration of large amounts of vitamin A in pregnant women can also cause fetal malformations, which must be noted.

Clinical manifestations of vitamin A poisoning

Vitamin A poisoning can be divided into the following two types: 1. acute type; 2. chronic type.

Vitamin A poisoning children pay more attention to eating habits

Vitamin A poisoning acute

Due to individual differences in the sensitivity of children to vitamin A, and different levels of vitamin A storage in the liver, the toxic doses can vary widely. In general, vitamin A injection of 300,000 IU can cause symptoms of poisoning within a few days. Presented as loss of appetite, irritability or lethargy, vomiting, bulging of the anterior palate, enlarged head circumference, suspicious craniotomy, and papilledema. Elevated intracranial pressure is common in the acute type, which may be caused by increased cerebrospinal fluid or malabsorption. Children with no signs of nervous system infection are easy to use, and suddenly have symptoms of increased intracranial pressure. Combined with a history of intake of large amounts of vitamin A, the symptoms disappear quickly after crediting vitamin A, and the diagnosis can be established.

Vitamin A poisoning chronic

The dosage of vitamin A amounts to tens of thousands of units per day. For example, if infants and young children consume 1500 IU per kilogram of body weight daily, symptoms of poisoning may occur in a few days. Early onset of irritability, loss of appetite, low fever, sweating, hair loss, and later typical bone pain symptoms, metastatic pain, may be accompanied by swelling of soft tissues, tender points without redness and heat signs, more common in long bones and limb bone Because long bones are embedded in the epiphysis, they can be short. Some cases have swelling and pain in the temporal and posterior occipital regions, which can be misdiagnosed as skull softening. Symptoms of increased intracranial pressure, such as headache, vomiting, wide and raised anterior condyle, separation of skull sutures, esotropia in both eyes, nystagmus, and diplopia are another characteristic of this disease, but they are rarer than the acute type. In addition, there are still itching, desquamation, rash, cleft lip and palate, dry hair, hepatosplenomegaly, abdominal pain, myalgia, bleeding, kidney disease, and hypoplastic anemia with reduced white blood cells. Increased blood alkaline phosphatase. It has been reported abroad that chronic liver and splenomegaly can cause liver cirrhosis, increase portal pressure, and even death.

Vitamin A poisoning diagnosis test

In addition to the above history of symptoms and signs, vitamin A poisoning should be checked as follows

1. X-ray examination is of special value for the diagnosis of this disease. It is characterized by abnormal tubular bone shape, bone resorption, and fracture; changes in the diaphragm and soft tissue swelling; new bone formation under the periosteum at the backbone; .

2. Cerebrospinal fluid pressure increased to 2.55kPa (260mmH2O), cells and sugars were in the normal range, and some people found that the protein was lowered or lower than normal.

3, check the serum vitamin A, often up to 1,000 ~ 6000g / L.

Diagnostic criteria for vitamin A poisoning

Vitamin A diagnostic criteria:

1. One application of vitamin A over 300,000 international units can cause acute poisoning. Long-term (weeks or months) overdose of vitamin A can cause chronic poisoning.

2. Symptoms of acute poisoning include nausea, vomiting, lethargy, anterior diaphragmatic swelling, diplopia, and cranial nerve palsy. Symptoms of chronic poisoning include irritability, loss of appetite, itching, loss of weight, cleft palate, long bone pain, hepatosplenomegaly, scaling of hands and feet, softening of the skull, and increased intracranial pressure.

3. X-ray long bone plain film: thickening of the middle cortex.

4. Increased serum vitamin A content (> 3.5 mol / l, 100 g / dl).

Differential diagnosis of vitamin A poisoning

The clinical manifestations of vitamin A poisoning can be divided into acute poisoning (more than 300,000 IU in a single injection) and chronic poisoning (daily infants and young children consume 50,000 to 100,000 IU, and poisoning can occur after 6 months). The diagnosis of acute poisoning is not difficult, and chronic poisoning is easily misdiagnosed. Its main performance is:

Special attention for children with vitamin A poisoning

1. General symptoms: irritability, irritability, sharp loss of appetite, low fever, no weight gain, and poor spirit.

2. Symptoms of skin: itching, desquamation, sweaty hair, easy to fall off, cleft lip and palate.

3. Bone symptoms: limb pain, swelling of soft tissue, prominent jaw on both sides.

4, X-ray characteristics: changes in tubular bone, new bone formation under the periosteum, periosteal hyperplasia, severe cases of epiphyseal embedding deformities, premature closure of the epiphysis and diaphysis, skull changes, cranial sutures widened, anterior hemorrhoids enlarged.

Chronic feature-soft tissue swelling

In order to avoid misdiagnosis or less misdiagnosis, clinicians should be alert when the above symptoms and bone X-ray manifestations occur, and they should closely observe and inquire about the history of vitamin A administration. In particular, the misunderstanding that cod liver oil is "nutrition medicine, the more the better" should be corrected. In the treatment of rickets, the use of pure vitamin D preparations should be promoted. Due to the improper proportion of vitamin A and D in many cod liver oils (including dosage forms containing 5,000 IU, D 5000 IU, or A 10,000 IU, D 5,000 IU per gram of vitamin A), vitamin A content is high, and vitamin D is not enough to treat rickets. When increasing the dose, vitamins are often caused A poisoning. Once diagnosed, the drug should be stopped immediately and the intake of carrots should be reduced. Vitamin E 150mg / d can be used 3 times a day to promote the excretion of vitamin A. Generally, clinical symptoms gradually disappear within 1 to 2 weeks, but the plasma vitamin A concentration recovers. It usually takes months.

Vitamin A poisoning treatment

1. Once the diagnosis of biotin A poisoning is confirmed, it should be stopped immediately. The subjective symptoms usually disappear quickly within 1 to 2 weeks, but the vitamin A in the blood can maintain a high level for several months.

Diet should pay attention to avoid causing vitamin A poisoning

2. The skull X-ray signs can return to normal within 6 weeks to 2 months, but the long bone X-ray signs recover slowly. It usually takes about six months. Therefore, vitamin A should be stopped within a few months to avoid recurrence of symptoms. When using concentrated cod liver oil or vitamin A preparations, do not exceed the required amount.

3. When large doses must be used, the time of medication should be strictly limited to avoid poisoning. It has been reported that pregnant women taking too much vitamin A in the early stages can cause miscarriage and fetal malformations. Therefore, the daily dosage of pregnant women should not exceed 5,000 IU.

Vitamin A poisoning complications

There are many complications of vitamin A poisoning, especially children are more susceptible to complications. There are the following:

Asperger's syndrome, whooping cough, intestinal piriformis, asthmatic bronchitis, Kawasaki disease

Complications-Kawasaki disease

, Hemorrhagic shock, encephalopathy syndrome, massive amniotic fluid aspiration, fifth day syndrome, multiple tics syndrome, thalassemia, open arterial ducts, thrush, ADHD, tic disorders in children, pancreatic insufficiency in children, neutral Granulocytopenia Syndrome, Children's Learning Disability, Children Stuttering, Children's Sleep Disorders, Child Enuresis, Child Enuresis, Child Abdominal Pain, Child Autism, Childhood Acute Benign Myositis, Childhood Mood Disorders, Child Schizophrenia , Anal atresia, anal atresia, expired babies.

Vitamin A poisoning prevention measures

Promote common knowledge about nutrition and hygiene, and correct parents' abuse of vitamin A preparations and poor dietary habits. For example, animal livers are organs that store vitamin A and are rich in nutrients, but they should not be eaten every day. Food should be varied. Prevent iatrogenic vitamin A poisoning.

The daily physiological requirement of vitamin A is 2000IU. When using concentrated cod liver oil or vitamin A preparations, do not exceed the required amount; when large doses must be used, the medication time should be strictly limited. The supply of vitamin A and carotene should be stopped immediately after poisoning, because carotene can be broken down into vitamin A in the body. The acute symptoms of vitamin A poisoning generally disappear within 72 hours to 1 week after the drug is stopped, and other symptoms have also gradually reduced and improved. Skull X-ray signs recovered within 6 weeks to 2 months; long bone X-ray signs recovered slowly, often taking about six months, and high levels of serum vitamin A could last for months. Vitamin K is available for those with bleeding.

Taking cod liver oil to your child is the only way to prevent poisoning. These include:

1. Strictly follow the doctor's advice to take cod liver oil preparations for children. Generally, infants under 1 year old can give 3-4 drops of concentrated cod liver oil per day, not more than 6 drops.

2. When preventing infantile rickets, try to supplement your child with a pure vitamin oral preparation that does not contain vitamin A.

Fruits high in vitamin A

3. If it is really necessary to supplement the child with large doses of vitamin A due to special circumstances, the doctor should strictly limit the time of medication.

4. During the period of taking cod liver oil, once the child is found to have suspicious symptoms of vitamin A poisoning, he should stop taking it immediately and take the child to the hospital for treatment in time.

Application of Vitamin A in Beijing. D fortified fresh milk to feed children (containing vitamin A2000IU / L), it was observed that vitamin A deficiency was effectively prevented, and no symptoms of excessive vitamin A were seen.

Medical staff must understand and grasp the dosage of vitamin A preparations and teach them to parents. They must not abuse vitamin A preparations and change the misconception that cod liver oil is a tonic, a higher dose and a longer time are not harmful. Do not eat large amounts of animal liver in diet. If vitamin D is needed for the treatment of consultations, a pure vitamin D preparation should be used.

Vitamin A poisoning prognosis

The prognosis for adults and children is excellent. After stopping taking vitamin A, symptoms and signs usually disappear within 1 to 4 weeks. However, the prognosis of fetuses whose mothers take high doses of vitamin A remains.