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:
