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A.D.A.M. Medical Encyclopedia [Internet]. Atlanta (GA): A.D.A.M.; 2013.
A.D.A.M. Medical Encyclopedia.
Hypervitaminosis A is having too much vitamin A in the body.
Causes, incidence, and risk factors
There are two types of vitamin A hypervitaminosis:
- Acute -- caused by taking too much vitamin A over a short period of time
- Chronic -- occurs when too much of the vitamin is present over a longer period
Chronic vitamin A toxicity develops after taking too much vitamin A for long periods.
Symptoms
- Abnormal softening of the skull bone (craniotabes -- infants and children)
- Blurred vision
- Bone pain or swelling
- Bulging fontanelle (infants)
- Changes in consciousness
- Dizziness
- Double vision (young children)
- Drowsiness
- Headache
- Irritability
- Liver damage
- Nausea
- Poor weight gain (infants and children)
- Vision changes
- Vomiting
Signs and tests
- Bone x-rays
- Blood calcium test
- Cholesterol test
- Liver function test
- Blood test to check vitamin A levels
Treatment
Treatment involves simply stopping the use of too much vitamin A.
Expectations (prognosis)
Most people fully recover.
Complications
- Excessively high calcium levels
- Failure to thrive in infants
- Kidney damage due to high calcium
- Liver damage
Taking too much vitamin A during pregnancy may cause abnormal development in the developing baby. Talk to your health care provider about eating a proper diet while you are pregnant.
Calling your health care provider
Call your health care provider if you think that you or your child may have taken too much vitamin A, or you have symptoms of excess vitamin A.
Prevention
To avoid hypervitaminosis A, avoid taking more than the recommended daily allowance of this vitamin. Recent emphasis on vitamin A and beta carotene as anticancer vitamins may contribute to chronic hypervitaminosis A, if people take more than is recommended.
References
- Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, PA: Saunders Elsevier; 2011:chap 225.
- Zile MH. Vitamin A deficiencies and excess. In: Kliegman RM, Stanton BF, St. Geme JW III, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 45.
Review Date: 6/2/2012.
Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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Vitamin A supplementation given to mothers of newborn children or infants below six months of age for preventing death and illnesses in the first year of life
Vitamin A deficiency is a significant public health problem in low and middle income countries. Vitamin A supplementation (VAS) given to children between the age of six months and five years has been shown to reduce deaths in these settings. Infants below one year of age are at higher risk of developing vitamin A deficiency. There are two possible ways to enhance the vitamin A status of these infants. Firstly, VAS can be given to lactating mothers to increase the vitamin A content of their breast milk, and secondly, VAS can be given direct to young infants below six months of life. Researchers have examined the potential role of these two strategies in preventing death and illness in the first year of life.
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