Vitamin A deficiency
Vitamin A deficiency causes xerophthalmia, from night blindness to corneal melting, and raises child deaths from infection. It is preventable by six-monthly doses and diet.
WHO classification of xerophthalmia
| Code | Sign | What you see |
|---|---|---|
| XN | Night blindness | The child cannot see in dim light; the mother says the child stumbles at dusk |
| X1A | Conjunctival xerosis | Dry, dull, wrinkled conjunctiva that has lost its shine |
| X1B | Bitot's spots | Foamy, greyish-white, triangular patches on the conjunctiva, usually beside the cornea |
| X2 | Corneal xerosis | Dry, hazy, dull cornea |
| X3A | Corneal ulcer or keratomalacia, less than one-third of the cornea | Ulcer or melting of part of the cornea: an emergency |
| X3B | Corneal ulcer or keratomalacia, one-third or more | Large melting; usually ends in blindness |
| XS | Corneal scar | White scar left after healing |
| XF | Xerophthalmic fundus | Small white spots on the retina |
Causes and who is at risk
- Low intake of retinol (milk, eggs, liver, fish) and of beta-carotene (green leafy vegetables, yellow-orange fruits and vegetables).
- Very little fat in the diet, so carotene is poorly absorbed.
- Infections: measles, diarrhoea and roundworms increase losses and lower absorption.
- PEM: too little protein means too little retinol-binding protein, so vitamin A cannot be carried out of the liver.
- Early weaning or discarding colostrum, which is rich in vitamin A.
- Most at risk: preschool children, pregnant and lactating women, poor families.
Effects beyond the eye
- Lower immunity: more severe measles, diarrhoea and respiratory infections, and higher child deaths.
- Dry, rough skin with raised bumps around hair follicles (follicular hyperkeratosis).
- Poor growth, and anaemia, because vitamin A helps the body use iron.
WHO criteria: VAD is a public health problem in preschool children when
Preventive strategies
| Approach | Time scale | What it involves |
|---|---|---|
| Vitamin A supplementation (prophylaxis) | Short-term | 1 lakh IU by mouth at 9 months with the MR vaccine, then 2 lakh IU every 6 months up to 5 years: 9 doses in all |
| Food fortification | Medium-term | Vitamin A added to edible oil and milk under FSSAI fortification standards |
| Dietary diversification | Long-term | Drumstick leaves, amaranth, agathi, carrot, pumpkin, papaya, mango; milk and eggs; kitchen gardens; a little oil with vegetables |
| Public health measures | Long-term | Measles immunisation, breastfeeding with colostrum, diarrhoea control, deworming, nutrition education |
During the six-monthly vitamin A rounds, the ANM and anganwadi worker give the dose by spoon and record it on the child's Mother and Child Protection card. Promoting drumstick-leaf poriyal and a papaya tree in the backyard gives a lasting, low-cost supply.
2 marks: “What are Bitot's spots?” Foamy, greyish, triangular patches on the conjunctiva beside the cornea; stage X1B of xerophthalmia in vitamin A deficiency.
5 marks: “Give the WHO classification of xerophthalmia.” XN, X1A, X1B, X2, X3A, X3B, XS and XF, with one line on what each looks like.
10 marks: “Discuss the causes, clinical features and prevention of vitamin A deficiency.” Define; causes; WHO stages table; effects beyond the eye; prevention: short-term prophylaxis doses, medium-term fortification, long-term diet and kitchen gardens; the 1970 national programme.
Eye signs go dark → dry → melt → scar: XN (night blindness) → X1 (dry conjunctiva, Bitot's spots) → X2 (dry cornea) → X3 (ulcer, melting) → XS (scar).