Question

Case 2: An 88-year-old woman was seen by an ophthalmologist at an eye clinic in Toronto, complaining about itchy, burning eyes. An examination of the cornea revealed dry patches on the surface of the eye, consistent with xeropthalmia. The patient reported having food intolerances for the last 20 years and following a strict "diet" consisting of rice, canned tuna and vitamin B supplements. Serum retinol levels were found to be extremely low. The doctors prescribed megadoses of vitamin A which reversed the xeropthalmia within a few weeks. Question 1 1 pts Which statement best describes the link between vitamin A deficiency and xeropthalmia? No answer text provided. When vitamin A is deficient, mucus-secreting cells do not differentiate into epithelial cells. When vitamin A is deficient, immature epithelial cells do not differentiate into phagocytes. When vitamin A is deficient, immature epithelial cells do not differentiate into mucus-secreting cells.

Answer 1

Q.1. Answer- when vitamin A is deficient, immature epithelial cells do not differentiate onto mucus- secreting cells

Explanation- The vitamin A deficiency for long time causes inability of immature epithelial cells to differentiate into mucus-secreting cells known as goblet cells. Goblet cells secretes mucus mucin that is mixed into tears and destributes tears uniformly on the surface of eye. Due to vitamin A deficiency goblet cells are not formed by epithelial cells and lead to dryness of eye.

In this case, 88-year old women experiences burning and itchy eye and her examination of cornea revealed dry patches on the surface of eye. This is consistent with xeropthalmia and specifically conjunctival xerosis. Conjunctival xerosis is caused by insufficient mucus secretion by goblet cells. As women was on strict diet her serum retinol level was severely low that indicates vitamin A deficiency. Conjunctival xerosis can be cured by vitamin A supplement as in this case megadose of vitamin A reversed xeropthalmia within few weeks.