Hypervitaminosis A
Key points
- Hypervitaminosis is the excessive accumulation of a vitamin; this condition involves too much vitamin A.
- 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.
- Treatment Treatment involves simply stopping the use of excess vitamin A.
- Recent studies show that too much vitamin A taken during pregnancy can cause abnormal development in the fetus.
Alternative names
Vitamin A toxicity
Definition
Hypervitaminosis is the excessive accumulation of a vitamin; this condition involves too much vitamin A.
Causes, incidence, and risk factors
There are two types of vitamin A toxicity:
- Acute: caused by taking too much vitamin A over a short period of time
- Chrinic: occurs when the excess 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 excessive doses of the substance for extended 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
o hair loss
o seborrhea
o cracking at corners of the mouth - Irritability
- Decreased appetite
- Poor weight gain (infants and children)
- Vomiting
- Drowsiness
Signs and tests
- Serum vitamin A levels
Written and revised by
Gerald Hurowitz, M.D.
Our doctors write and review articles for accuracy and keep them up to date.
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