Review Question - QID 217073

This patient with worsening night vision, likely xerophthalmia (abnormal eye dryness that manifests as a “gritty” sensation), dry skin, and Bitot spots (raised lesions on the temporal conjunctiva) most likely has vitamin A deficiency. Gastric bypass surgery can lead to poor intestinal absorption of fat-soluble vitamins and subsequently vitamin A deficiency.

Vitamin A functions as an antioxidant, constituent of visual pigments, and stimulator of the immune system. It also is essential for the differentiation of epithelial cells into specialized tissues. Vitamin A can be found in green/yellow vegetables and liver tissue. Vitamin A deficiency in the developing world is usually due to insufficient dietary intake. In the developed world, vitamin A deficiency is most often caused by disorders associated with fat malabsorption, such as cystic fibrosis, cholestatic liver disease, Crohn disease affecting the small bowel, short gut syndrome, and patients that have undergone some types of bariatric surgery that would lead to intestinal malabsorption. Clinically, vitamin A deficiency manifests with poor night vision, xerophthalmia, dry skin, and Bitot spots (gray-white lesions with sharp margins resulting from the keratinization of the epithelium of the conjunctiva).

Wiseman et al. review the epidemiology, pathophysiology, and clinical manifestations of vitamin A deficiency.

Figure/Illustration A shows Bitot spots (blue box). These consist of metaplastic conjunctival epithelium and tangles of keratin admixed with a gas-producing bacteria.

Incorrect Answers:
Answer 1: Chronic kidney disease (CKD) is associated with low levels of B vitamins, iron, vitamin C, vitamin D, and calcium. CKD may cause insufficient excretion and excess of vitamins A, E, and K.

Answer 2: Consumption of wild game liver is associated with vitamin A excess, not deficiency. Wild game liver contains very high levels of vitamin A. Vitamin A excess manifests clinically with arthralgias, periosteal proliferation, alopecia, and idiopathic intracranial hypertension.

Answer 3: Isotretinoin treatment is associated with vitamin A excess, not deficiency. Isotretinoin is a vitamin A derivative, and it is metabolized to vitamin A in the body. Clinically, isotretinoin is used to treat severe acne.

Answer 5: Ulcerative colitis rarely causes vitamin A deficiency. Vitamin A is absorbed in the small intestine, and ulcerative colitis rarely affects the small intestine. However, Crohn disease can affect the entire gastrointestinal tract; therefore, Crohn disease that affects the small intestine can cause vitamin A deficiency.

Bullet Summary:
Vitamin A deficiency can be caused by fat malabsorption or insufficient dietary intake, and it manifests clinically as night blindness, xerophthalmia, and Bitot spots.