hypervitaminosis A

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vitamin A poisoning

A potentially fatal condition evoked by an acute or chronic excess of vitamin A (> 20,000 IU) for more than two weeks.

Clinical findings
Bone pain, dry skin, gastrointestinal complaints (nausea, vomiting, constipation, diarrhoea), increased intracranial pressure, poor growth in children; affected infants may develop bulging fontanelles, craniotabes (softening of skull bones), pseudotumour cerebri, papilledema, drowsiness, severe headaches, insomnia, jaundice, menstrual disorders, stress, weight loss, irritability, decreased appetite, pruritis, hair loss, seborrhoea, and cracking at corners of mouth.

hypervitaminosis A

Vitamin A toxicity, see there.

hypervitaminosis A (hīpurvī´təm-inō´sis),

n the effects of toxic doses of vitamin A. Manifestations include bone fragility, xeroderma, nausea, headache, and loss of hair.


a condition produced by ingestion or injection of excessive amounts of vitamins; symptom complexes are associated with excessive intake of vitamins A and D.

hypervitaminosis A
occurs mainly in cats, and is caused by a long-term diet consisting almost entirely of liver. Affected cats show neck pain and stiffness caused by a deforming cervical spondylosis. Other joints may be similarly affected. There is also hyperesthesia, irritability, anorexia, weight loss, and sometimes neurological deficits. Premature loss of teeth has also been reported.
hypervitaminosis D
caused by overdosing with vitamin D preparations as in milk fever prophylaxis and inappropriate treatment of disorders of dietary calcium and phosphorus, by errors in a diet mix, and oversupplementation of small puppies and kittens. Causes dystrophic soft tissue calcification, particularly nephrocalcinosis with subsequent renal failure. See also enzootic calcinosis.
References in periodicals archive ?
Infant hypervitaminosis A causes severe anemia and thrombocytopenia: evidence of a retinol-dependent bone marrow cell growth inhibition.
Hepatic injury from chronic hypervitaminosis a resulting in portal hypertension and ascites.
Hypervitaminosis A syndrome: a paradigm of retinoid side effects.