The recommended daily intake of Vitamin A for children 4-6 years of age is 1665 I.U. Administration of Vitamin A as Retinol in excess of 20,000 I.U./day for short periods (3 weeks to 3 months) has resulted in intoxication and occasionally may lead to death.

Vitamin A intoxication is a generalized syndrome, the signs of which include: desquamative and edematous dermatitis, bone pain and tenderness, edema of the extremities and face, irritability, hepatocellular dysfunction, and increased ICP (intracranial pressure). The clinical and roentgen manifestations of excessive doses of Vitamin A vary according to chronicity of the intake, the ingested volume, and patient age.

ACUTE HYPERVITAMINOSIS A: In the acute state the patient exhibits drowsiness, sluggishness, vomiting, irritability, severe headache, an irresistible desire to sleep, and peeling of the skin.

In children it may result in hydrocephalus with pronounced bulging of the fontanels, frequent vomiting, agitation, and insomnia.

The clinical manifestations appear about 12 hours after ingestion of the drug and last approximately 24-48 hours. Recovery is complete.

CHRONIC HYPERVITAMINOSIS A: In the first six months of life:

Symptoms may appear with a dose of not more than 60,000 units/day.

Anorexia, hyperirritability, tender swelling of the scalp, bulging of the fontanelles, and craniotabes are the major clinical manifestations.

Radiologically, there is generalized osteopenia and cup-shaped sharply demarcated and widened metaphysis. The skull may be thin and poorly mineralized. The sutural margins may be relatively dense (sclerosed).

In Children:

Clinical signs are anorexia, irritability, painful swelling of the limbs (usually after the first year of life), pruritus and loss of hair. Hepatic injury is a grave complication. The major roentgen manifestation is cortical hyperostosis of the long bones of the limbs, ulna and metatarsals, and thoracic cage. The metaphysis and epiphyseal ossification centers are characteristically normal. Widening of cranial sutures, hyperostosis in the occipital and temporal bones, slight dilation of the ventricles and thickening of the mandible have been reported in this age group. Arrest in growth of long bones is a permanent crippling sequela of Vitamin A poisoning, especially the femora at their distal ends.

In Adults:

Fatigue, malaise, headache, insomnia, diplopia, night sweats, abdominal discomfort, migratory limb pain, alopecia, brittle nails, rhagades, and hepatosplenomegaly are some of the clinical manifestations of chronic Vitamin A poisoning in adults. The patient may present the clinical appearance of pseudotumor cerebri. The skeleton may be normal, however, an increase in CSF pressure and dilatation of the ventricular system may occur. Hypervitaminosis A should not be confused with hypervitaminosis D, where the calcification is primarily in the soft tissues and the kidneys.

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