vitamin A deficiency and its diseases

Vitamin A

Vitamin A is essential for;

1.      maintenance of  body epithelium
2.      for immune function
3.      for synthesis of retinal photoreceptor protein -  rhodopsin

vitamin A deficient child faces a 25% greater risk of dying from a range of childhood ailments such as measles, malaria or diarrhoea.

vitamin A deficiency is an important causes of blindness among children, where dietary intake is insufficient

 Sources

Vegetable sources

1.      green leafy vegetable
2.      spinach
3.      carrot, tomato
4.      papaya, mango

Animal sources;

1.      liver
2.      meat
3.      cod liver oil
4.      egg yolk

Daily intake

For children;  1000--- 1200 IU

For school going children and adult 3000 IU

VITAMIN A DEFICIENCY

Causes of Vitamin A Deficiency

1. Inadequate intake (strict vegetarian diet)
2. Fat malabsorption
3. Crohn's ileitis
4. Pancreatic insufficiency
5. Cystic fibrosis
6. Cholestatic liver disease

Diseases due to vitamin A deficiency;

1. Night blindness  - earliest manifestation. Responds rapidly within 24– 48 hours  to vitamin A therapy
2. Conjunctival Xerosis
3. Corneal xerosis
4. Corneal ulcer & sec. bacterial infection
5. Keratomalacia

Conjunctival xerosis and BITOT spot

Conjunctival epithelium is transformed from columnar epithelium to stratified squamous epithelium

Charecteristics

1. loss of goblet  cells and keratinization of ocular surface.
2. BITOT’s spot (keratinized area) appears on temporal side as triangular patch in the interpalpabral area
3. Xerophthalmic fundus

Corneal xerosis

• Hazy lusterless dry appearance of cornea
• Corneal ulceration
• If  not treated, corneal perforation may occur
• Secondary bacterial infection is common.
• Progressive corneal necrosis keratomalacia may occur in advanced cases.

Treatment

W H O recommendation;

1. Oral vitamin A

          immediately upon diagnosis 200,000 IU

1.      next day    200,000IU

                                                             ii.      after 1---4 weeks 200,000IU

2. Ocular lubrication – artificial tears
3. Topical vitamin A ointment
4. Antibiotic to prevent secondary infection