Hypervitaminosis A

Alternative names:

vitamin A toxicity

Definition:

The excessive accumulation of vitamin A, either acutely or chronically.

Causes, incidence, and risk factors:

Acute vitamin A toxicity occurs when an infant ingests more that 300,000 units of vitamin A that you would buy over the counter. This represents about 15 capsules of vitamin A. The infant may develop a bulging fontanelle and a constellation of symptoms resembling a brain tumor. This group of symptoms is called pseudotumor cerebri (bulging fontanelle, papilledema [swelling of the optic disc], and double vision). Vomiting and drowsiness are common.

Chronic vitamin A toxicity develops after taking above-normal doses for extended periods. Bone pain and swelling of the bones is common. Craniotabes (in infancy, abnormal softening of the skull bones) can occur. Irritability, decreased appetite, puritis, and poor weight gain are common. There may be skin changes with hair loss and seborrhea, and cracking at the corners of the mouth. Increased intracranial pressure is seen in both acute and chronic forms.