5. Micronutrient Deficiencies

5.1. Vitamin A Deficiency

Vitamin A is critical for vision and epithelial integrity. In addition, vitamin A deficiency (VAD) is associated with disorders in hematopoiesis and immune function. Thus, treatment of such deficiency has beneficial effects for patients with anemia and improves the outcome of infections, particularly measles. VAD is associated with diets lacking fresh fruits and vegetables, as well as animal products, dairy products, and eggs. VAD has a dramatic global impact on health, with approximately 127 million preschool-age children and 20 million women affected worldwide. It has been estimated that unidentified VAD results in about 2 million deaths in young infants, particularly due to excess morbidity and mortality associated with measles (see Module 5). VAD is the most common preventable cause of childhood blindness in the world. It is also the most frequent deficiency syndrome among displaced populations.

The clinical features of VAD involving the ocular system are known as xerophthalmia. The stages of xerophthalmia include night blindness, conjunctival xerosis, and keratomalacia. Night blindness is the most prevalent and earliest stage of xerophthalmia resulting from the impact of VAD on the retinal epithelium. Since this symptom may precede any ­apparent physical findings, its occurrence must be assessed through a careful history. Conjunctival xerosis presents as a dry nonwettable, rough or granular surface, which can be seen using a hand-light. More advanced xerosis is associated with Bitot’s spots which are bubbly, foamy, or cheese-like patches visible on the conjunctival epithelium. Conjunctival xerosis may progress to ulceration or in the most advanced form to keratomalacia, its typical presentation being necrosis of the cornea.

It has been estimated that unidentified vitamin A deficiency results in about 2 million deaths in young infants, particularly due to excess morbidity and mortality associated with measles.

Supplementation

A diet containing sufficient amounts of foods rich in vitamin A is enough to prevent hypovitaminosis. When adequate amounts of vitamin A are not available through dietary sources, consider supplementation. Vitamin A supplementation has been shown to reduce pre-school child mortality by 25% to 35%, and to virtually eliminate nutritional blindness in many low- and middle-income countries.

In acute humanitarian emergencies, if an adequate diet was not available and a regular vitamin A supplementation program was not in place for the general population prior to the disaster, provide vitamin A supplementation to all children 6 months to 5 years of age at the first contact with the health care staff. Remember to check whether the child already received vitamin A as part of any mass vaccination campaign. Fortified foods with vitamin A and other essential micronutrients should be distributed during the recovery phase. Individuals with symptoms and signs of VAD should receive the recommended treatment. Table 4 shows preventive and treatment doses of vitamin A. Only provide preventive treatment with vitamin A when it is known that the population is deficient.

<6 months (<6 kg)
Treatment 50,000 IU
Preventive dosage 50,000 IU every 4-6 months
6-12 months (6-8 kg)
Treatment 100,000 IU
Preventive dosage 100,000 IU every 4-6 months
>1 year (>8 kg)
Treatment 200,000 IU
Preventive dosage 200,000 IU every 4-6 months
Women
Treatment 200,000 IU**
Preventive dosage 200,000 IU ≤ 8 weeks after delivery

Notes:

  • * Treat all cases of xerophthalmia and measles with the same age-specific dosage the next day and again 1 to 4 weeks later.
  • ** For women of reproductive age, give 200,000 IU only for corneal xerophthalmia; for milder eye signs (night blindness or Bitot’s spots), give 5,000-10,000 IU per day or ≤25,000 IU per week for ≥4 weeks.