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Hypervitaminosis A

Definition

Hypervitaminosis means you having too much of a certain vitamin stored in your body. People with hypervitaminosis A have too much vitamin A.

Alternative Names

Vitamin A toxicity

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 -- happens when too much of the vitamin is present over a longer period

In an infant, the sudden intake of too much vitamin A may cause a bulging fontanelle ("soft spot" on the head), and symptoms resembling those of a brain tumor. This group of symptoms is called pseudotumor cerebri and includes a bulging fontanelle, papilledema (swelling of the optic disc), and double vision. Vomiting and drowsiness are common.

The symptoms in adults are less specific. Headache, visual changes, and impaired consciousness suggestive of pseudotumor cerebri may occur. Other symptoms may include nausea, vomiting, dizziness, and blurry vision.

Chronic vitamin A toxicity develops after taking too much vitamin A for long periods. Bone pain and swelling of the bones is common, often associated with high levels of calcium in the blood. Other symptoms include hair loss, high cholesterol, liver damage, and vision problems. Symptoms are often subtle and may include fatigue, malaise, and nausea.

In children, hypervitaminosis A can cause craniotabes (abnormal softening of the skull bones). Irritability, decreased appetite, itchy skin, and poor weight gain are common. There may be skin changes with seborrhea (extremely oily skin and hair), and cracking at the corners of the mouth.

Increased intracranial pressure is seen in both acute and chronic forms.

Symptoms

• Bulging fontanelles (infants)
• Bone pain or swelling
• Craniotabes (infants and children)
• Skin and hair changes
  • Hair loss
  • Seborrhea
  • Cracking at corners of the mouth
  • Yellow discoloration of the skin
  • Higher sensitivity to sunlight
  • Skin peeling
• Irritability
• Decreased appetite
• Poor weight gain (infants and children)
• Vomiting
• Drowsiness
• Double vision (young children)
• Gynecomastia (swelling of breast tissue in men)
• Impotence and ejaculation failure

Signs and tests

• Serum vitamin A levels
• A history of taking too much vitamin A for a short or long period of time
• Bone calcification (hardening)
• High blood calcium levels
• High serum creatinine (suggestive of kidney damage)

Treatment

Treatment involves simply stopping the use of too much vitamin A.

Expectations (prognosis)

Full recovery is the most likely outcome.

Complications

• Failure to thrive
• Excessively high calcium levels
• Kidney damage due to high calcium
• Osteoporosis
• Liver damage
• Prostate cancer

Recent studies show that too much vitamin A taken during pregnancy can cause abnormal development in the fetus. Consult your physician about a proper diet.

Calling your health care provider

Call your health care provider if you think that you or your child may have taken vitamin A in excess or if you have symptoms that may be linked with 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 anti-cancer vitamins may contribute to chronic hypervitaminosis A, if well-meaning people increase the dosage of vitamins beyond recommended values. More is not always better!

Review Date:8/8/2006
Reviewed By:Robert Hurd, MD, Department of Biology, College of Arts and Sciences, Xavier University, Cincinnati, OH. Review provided by VeriMed Healthcare Network

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