Clinical case of manifestation of toxic keratitis with vitamin A intoxication

Abstract

Vitamins are a group of organic compounds that are required to support life and perform biological functions of a living organism. They participate in humoral regulation, perform enzymatic and catalytic functions, their deficiency can result in the development of serious life-threatening diseases. However, taking too much of some vitamins can also be dangerous for a human. In particular, hypervitaminosis A can lead to the development of toxic keratitis. Hypervitaminosis A can arise after consumption of large doses of retinoids, which are efficiently absorbed and slowly excreted; hypervitaminosis can result from both one-time use of large amounts of vitamin A and long-term use of relatively moderate doses. Chronic overdose of this vitamin may cause skin itching, dermatitis, skin pigmentation disorders, dry oral and conjunctiva mucous membranes, hair loss, increased brittleness of nails, nosebleeds, destruction of bone and cartilage tissue, toxic hepatitis, and coma in severe cases. Doctors often use vitamin A to treat some dermatoses (acne), while the cumulative doses of drugs can be significantly higher than the allowed ones. This article presents a rare clinical case of manifestation of toxic keratitis in a patient receiving vitamin A at doses exceeding therapeutic ones. The patient managed to restore the integrity of the cornea and get rid of keratitis while receiving long-term local instillations of drops, including taurine.