Vitamin A Deficiency

KEY FEATURES

• One of the most common vitamin deficiency syndromes in developing countries

• Most common cause of blindness in developing countries

• In the United States, occurs most commonly in older adults and patients with malabsorption conditions

CLINICAL FINDINGS

• Night blindness (early)

• Dryness (xerosis) of conjunctivae and small white patches on the conjunctivae (Bitot spots) are early signs

• Ulceration and necrosis of the cornea (keratomalacia), perforation, endophthalmitis, and blindness are late manifestations

• Xerosis and hyperkeratinization of the skin

• Loss of taste

DIAGNOSIS

• Abnormalities of dark adaptation

• Serum vitamin A levels below normal range of 30–65 mg/dL

TREATMENT

• Night blindness, poor wound healing, and other signs of deficiency: vitamin A, 30,000 international units orally once daily for 1 week

• Potential antioxidant effects of beta-carotene can be achieved with supplements of 25,000–50,000 IU