Hypervitaminosis A Classification and external resources
ICD-10	E67.0
ICD-9	278.2
DiseasesDB	13888
eMedicine	med/2382

Hypervitaminosis A refers to the effects of excessive vitamin A (specifically retinoid) intake. Image File history File links No higher resolution available. ... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // E00-E35 - Endocrine diseases (E00-E07) Disorders of thyroid gland (E00) Congenital iodine-deficiency syndrome (E01) Iodine-deficiency-related thyroid disorders and allied conditions (E02) Subclinical iodine-deficiency hypothyroidism (E03) Other hypothyroidism (E030) Congenital hypothyroidism with diffuse goitre (E031) Congenital hypothyroidism without goitre (E032) Hypothyroidism due to medicaments and other... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Disease Bold textDatabase is a free website that provides information about the relationships between medical conditions, symptoms, and medications. ... eMedicine is an online clinical medical knowledge base that was founded in 1996. ... The structure of retinol, the most common dietary form of vitamin A Vitamin A is an essential human nutrient. ...

Presentation

Effects include:

• birth defects
• liver problems,
• reduced bone mineral density that may result in osteoporosis
• coarse bone growths
• skin discoloration
• hair loss
• excessive skin dryness/peeling (desquamation)

A congenital disorder is a medical condition or defect that is present at or before birth (for example, congenital heart disease). ... The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ... A bone mineral density (BMD) test, also called a bone mass measurement, is used to measure bone density and determine fracture risk for osteoporosis. ... Osteoporosis is a disease of bone that leads to an increased risk of fracture. ... Baldness (formally alopecia) is the state of lacking hair where it usually would grow, especially on the head. ... Desquamation is the shedding of the outer layers of the skin. ...

Signs

Signs of acute toxicity include nausea and vomiting, headache, dizziness, blurred vision, and loss of muscular coordination. For other uses, see Nausea (disambiguation). ... Heaving redirects here. ... A headache (cephalgia in medical terminology) is a condition of pain in the head; sometimes neck or upper back pain may also be interpreted as a headache. ... Many different terms are often used to describe what is collectively known as dizziness. ... In psychology, visual perception is the ability to interpret information from visible light reaching the eyes. ... For other uses of Muscle, see Muscle (disambiguation). ...

Pathophysiology

Hypervitaminosis A occurs when the maximum limit for liver stores of retinoids is exceeded. The excess vitamin A enters the circulation causing systemic toxicity. Vitamin A in the form of betacarotene is only selectively converted into retinoids, and hence does not cause toxicity. Carotene is a terpene, an orange photosynthetic pigment, important for photosynthesis. ...

Although hypervitaminosis A can occur when large amounts of liver are regularly consumed, most cases of vitamin A toxicity result from an excess intake of vitamin A in the form of vitamin supplements. Toxic symptoms can also arise after consuming very large amounts of preformed vitamin A over a short period of time. (See Polar-bear liver below.)

Vitamin A causes cells to swell with fluid, too much vitamin A causes them to rupture in hypoosmotic environments, hence the toxicity. Toxicity has been shown to be mitigated through vitamin E, Cholesterol, Zinc, Taurine and Calcium.

Recommended supplement limits

The Institute of Medicine has established Daily Tolerable Upper Levels (UL) of intake for vitamin A from supplements that apply to healthy populations, in order to help prevent the risk of vitamin A toxicity. These levels for preformed vitamin A in micrograms (µg) and International Units (IU) are: In the metric system, a microgram is 1/1,000,000 of a gram, or 1/1000 of a milligram, is one of the smallest units of weight/mass commonly used. ... In pharmacology, the International unit (IU, alternatively abbreviated UI, from French unité internationale) is a unit of measurement for the amount of a substance, based on measured biological activity (or effect). ...

• 0-3 years: 600 µg or 2000 IU
• 4-8 years: 900 µg or 3000 IU
• 9-13 years: 1700 µg or 5665 IU
• 14-18 years: 2800 µg or 9335 IU
• 19+ years: 3000 µg or 10,000 IU

The dose over and above the RDA is among the narrowest of the vitamins and minerals. Possible pregnancy, liver disease, high alcohol consumption, and smoking are indications for close monitoring and limitation of vitamin A administration. However, vitamin A has also been repeatedly tested and used therapeutically over several decades in larger amounts, 100,000 - 400,000 IU total dosage, for treatment of severe pediatric measles in areas where vitamin A deficiency may be present, in order to reduce childhood mortality.^[1][2] The Dietary Reference Intake is a system of nutrition recommendations from the Institute of Medicine of the USA National Academy (IOM). ...

Toxicity from eating liver

The liver of certain animals — including the polar bear, seal, and husky — is unsafe to eat because it is extraordinarily high in vitamin A. This danger has long been known to the Inuit and has been recognized by Europeans since at least 1597 when Gerrit de Veer wrote in his diary that, while taking refuge in the winter in Nova Zembla, he and his men became gravely ill after eating polar-bear liver.^[3] In 1913, Antarctic explorers Douglas Mawson and Xavier Mertz were both poisoned, the latter fatally, from eating the liver of their sled dogs.^[4] The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ... This article is about the animal. ... Families Odobenidae Otariidae Phocidae Pinnipeds (fin-feet, lit. ... Sled dogs, known also as sleigh dogs, sledge dogs or sleddogs are a group of dogs that are used to pull a wheel-less vehicle on runners (a sled or sleigh) over snow or ice, by means of harnesses and lines. ... The structure of retinol, the most common dietary form of vitamin A Vitamin A is an essential human nutrient. ... For other uses, see Inuit (disambiguation). ... Novaya Zemlya (Russian: , lit. ... Year 1913 (MCMXIII) was a common year starting on Wednesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Tuesday of the 13-day-slower Julian calendar). ... For other uses, see Antarctica (disambiguation). ... “Mawson” redirects here. ... Xavier Mertz (1883–1912) was a Swiss explorer, principally famous for his adventures in the Antarctic. ... Sled dogs, known also as sleigh dogs, sledge dogs or sleddogs are a group of dogs that are used to pull a wheel-less vehicle on runners (a sled or sleigh) over snow or ice, by means of harnesses and lines. ...

Vitamin A itself was not discovered until 1917. The structure of retinol, the most common dietary form of vitamin A Vitamin A is an essential human nutrient. ... 1917 (MCMXVII) was a common year starting on Monday of the Gregorian calendar (see link for calendar) or a common year starting on Tuesday of the 13-day slower Julian calendar (see: 1917 Julian calendar). ...

The livers of many other animals have lower levels of vitamin A and are commonly eaten. The liver is the largest internal organ in the human body, and is an organ present in vertebrates and some other animals. ...

References

1. ^ Hussey GD, Klein M (1990). "A randomized controlled trial of vitamin A in children with severe measles". NEJM 323: 160–164. 
2. ^ Ellison JB (1932). "Intensive vitamin therapy in measles". Br Medical J ii: 708–711. 
3. ^ Paul Lips (2003-05-08). "Hypervitaminosis A and fractures". N Engl J Med 348: 1927–1928. doi:10.1056/NEJMe020167. PMID 12540650. 
4. ^ Student BMJ Man's best friend?

A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ...

See also

• Vitamin poisoning
• Xavier Mertz (first documented death of Hypervitaminosis A after consuming a sled dog's liver during an Antarctic expedition)

Vitamin poisoning, or hypervitaminosis, refers to a condition of high storage levels of vitamins, which can lead to toxic symptoms. ... Xavier Mertz (1883–1912) was a Swiss explorer, principally famous for his adventures in the Antarctic. ...

External links

• Facts about Vitamin A and Carotenoids, from the National Institutes of Health's Office of Dietary Supplements.