hypovitaminosis A

Hypovitaminosis A results from inadequate intake of vitamin A, fat malabsorption, or liver disorders and produces a variety of epithelial alterations.

Epidemiology

The World Health Organization currently estimates that 45-122 countries have a vitamin A deficiency of public health significance based on the prevalence of night blindness and biochemical vitamin A deficiency (serum retinol concentration <0.70 µmol/L), respectively, in preschool-age children.

Night blindness is estimated to affect 5.2 million preschool-age children (33.3% globally) and 9.8 million pregnant women (15.3% globally). Regions of Africa and South-East Asia were found to be the most affected.

Clinical presentation

Manifestations include:

  • dry and scaly skin
  • increased intracranial pressure
  • ocular effects
    • xerophthalmia (dry eye) - common cause of blindness in young children in developing countries
    • poor night vision/night blindness
    • photophobia
  • decreased immunity
  • squamous metaplasia
  • renal tract stones from pelvic keratinization
  • in infancy
    • susceptibility to infection
    • anemia
    • cranial nerve injury
    • growth retardation

Radiographic features

  • slow bone development
  • widening of the cranial sutures with bulging fontanelles

Treatment and prognosis

Administration of vitamin A given orally or parenterally, if malabsorption is the cause of the deficiency.

See also

Siehe auch: