Emergent Care / Stabilization:
Care is supportive. Recovery is generally rapid upon discontinuation of medication or supplementation unless exposure has been chronic, leading to irreversible end-organ damage (cirrhosis or renal failure). In those who develop consequent pseudotumor cerebri, use of acetazolamide to reduce intracranial pressure (ICP) may be considered.

Diagnosis Overview:
Hypervitaminosis A is a rare but potentially serious condition that results from excessive vitamin A in the body, leading to multisystem toxicity. This can result from excessive consumption / use of vitamins, supplements, vitamin A rich foods, or medications that contain vitamin A or provitamin A compounds. Hypervitaminosis A can be acute (ie, high consumption over a few hours) or chronic. Vitamin A is a fat-soluble vitamin, so excessive consumption builds up in fat stores, especially in the liver, and can lead to toxicity. Vitamin A toxicity occurs more readily in children than adults.

Vitamin A doses are expressed in retinol activity equivalents (RAE). One RAE is equal to 1 mcg of retinol, or 3.33 international units (IU) of retinol. Recommended daily intake of vitamin A varies from 300 mcg RAE for a 1-year-old child to 1300 mcg RAE for a lactating female. The upper intake limit (UIL) of vitamin A in an adult is 3000 RAE.

Acute vitamin A toxicity in adults occurs with consumption of 100 000 RAE or more in a short period. Classic symptoms include blurred vision, headache, nausea, vomiting, diarrhea, irritability, and impaired muscular coordination. In severe cases, increased ICP can be seen with pseudotumor cerebri.

Chronic vitamin A toxicity usually occurs when intake exceeds 8000 RAE per day for adults. Symptoms are seen in many organ systems, including dry and cracked skin, brittle nails and hair, hair loss, bone pain, joint pain, fatigue, headache, nausea, vomiting, bone spurs, calcinosis, and osteoporosis. Pseudotumor cerebri and hypothyroidism can be seen. Laboratory tests show increased transaminases, increased triglycerides, and increased cholesterol.

Hypervitaminosis A may also have teratogenic effects on a fetus, including microcephaly, cardiofacial malformations, central nervous system (CNS) abnormalities, cleft lip / palate, and urinary tract abnormalities.