all about VAD

1. VITAMIN A -
DEFICIENCY
DISORDERS
Dr. Abhishek Tiwari, MD,
Assistant Professor
Department of Community Medicine

2. Learning objectives
● To understand the importance of Vitamin A
● Its daily requirement
● The available sources of Vit A
● The spectrum of deficiency disorders
● Causes, prevention & control
● chicken eyes, bitots spot

3. Introduction – Vit. A
● Essential nutrient needed in small amount for
● Normal functioning of visual system
● Growth & development
● Maintainance of epithelial integrity
● Immune function
● Reproduction

4. Importance of Vit. A
● Essential for somatic function  growth, development
and differentiation of epithelial structures
● Essential for spermatogenesis, oogenesis, placental
development, fetal & embryonic growth
● Retinol – needed for Rhodopsin by rods, for dark vision
● Also has anti-infective properties

5. Problem magnitude
● Leading preventable cause of childhood blindness
● Globally - 30 % underfive are having VAD, 2% deaths
● SEARO – highest burden in preschool, 91.5 million <0.7
µmol/L and Night blindness 82.4%
● NNMB India 8 states – Bitots spot 0.8% rural preschool
● Blood VAD (retinol < 0.70 µmol/L ) 61%
● Severe blood VAD (retinol < 10 µg/dL ) 21.5%

6. Sources – Vitamin A (Retinol)
● Animal foods – liver, egg yolk, fish & meat
● Dairy products – butter, cheese, whole milk
● Beta-carotene – provitamin A precursor in GLV, yellow
fruits- papaya, mango, pumpkin (less bioavailable)
● Stored in liver (buffer)
● RDA – 0-12 mt – 350 µg. 1to6yr-390-510µg, 7to9yr-630 µg
● 10-17yr-770-1000 µg and adult man – 1000 µg women 840
µg, pregnancy 900 µg lactation 950 µg (ICMR 2020)

7. Vitamin A Defeciency - VAD
● A systemic disease that affects cells and organs, causing
“keratinizing metaplasia” in respiratory, urinary and
intestinal epithelium
● Goblet cell numbers are reduced  reuced mucus
secretion, reduced antimicrobial activity
● Thus protective tissue fails to regenerate & differentiate
● Gradual depletion leads to xerophthalmia

8. Classification of Xerophthalmia
XN Night blindness
X1A Conjunctival Xerosis
X1B Bitot’s spot
X2 Corneal Xerosis
X3A Corneal ulceration/ keratomalacia <1/3 corneal surface
X3B Corneal ulceration/ keratomalacia >1/3 corneal surface
XS Corneal Scar
XF Xerophthalmic fundus

9. Prevalence criteria for VAD
Indicator Minimum prevalence, %
XN Night blindness > 1
X1BBitot’s spot > 0.5
X2, X3A, X3B, Corneal Xerosis /
Corneal ulceration/ keratomalacia
> 0.001
XS Corneal Scar > 0.005
For determining the public health significance of spectrum of
VAD in 6mt to 6 yr

10. Indicators of Vit. A deficiency
Criteria Group
Public Health Importance
Mild Moderate Severe
Night Blindness
Children (24-
71mt)
<1% 1-5% ≥5%
Pregnant women ≥5%
Plasma retinol
< 0.70 µmol/L
Preschool
children/pregnant
women
≥2-≤10% ≥10-<20% ≥20%

11. XN - Night blindness
● Earliest manifestation, function of rods impaired, affected
child is unable to move around the house or
neighbourhood after dusk, unable to find their toys or
food
● Also known as “chicken eyes”. Difficult to recognize in
children who have not yet begun to crawl

12. X1A – Conjunctival Xerosis
● Loss of goblet cells & transformation of conjunctival
epithelium to stratified squammous type
● Conjucntiva becomes dry, roughened & corrugated with
fine droplets or bubbles on surface & appears like
● “SANDBANKS AT RECEDING TIDE”
● Xerosis – whitish, yellow triangular patch and is usually
seen in both eyes leads to Bitot’s spot
● Temporal, bulbar conjunctiva adjacent to limbus

13. X1B - Bitot’s Spot
Triangular
dry, whitish,
foamy
appearing
lesions,
located m/c
on temporal
side

14. X2 - Corneal Xerosis
● Dryness of cornea, absence of
tear cells most obviously
manifest in the inferonasal
part of cornea (the part
covered last by eyelids)
● Clinically apparent as
punctate white spots over
cornea which stains brightly
with fluorescein

15. X3A &B - Corneal ulceration/ keratomalacia
● Corneal ulceration/ keratomalacia <1/3 corneal surface
● Loss of corneal epithelium with or without underlying
stromal defect.
● Xerosis predisposes cornea to infection due to loss of tear
film, which penetrate beneath and erode stromal tissues
● Keratomalacia – complete erosion of stromal tissues at
site of ulcer
● Corneal Ectasia – bulging out of cornea (thinning)

16. XS - Corneal Scar
● Healing response at
ulceration site 
opacity – Scar
● Nebular, macular or
leukomatous as per
severity
● Staphyloma – Iris
adherent to corneal scar

17. Causes
● Demographic features – low SES, developing countries,
illeterate, overcrowded slums, low sanitation & hygiene
● Age – preschool primarily, due to susceptibility to
infections, increased requirements, may occur at any age
● Feeding practices – rare in breast fed (absorbable retinol)
● At start of complementary feeding
● low vit A diet, SEA where rice is staple (no β carotene)

18. Causes
● Decreased bioavailability of provitamin A carotenoids as
in fat malabsoption, liver disorders
● Interference with absorption or storage, celiac disease,
cystic fibrosis, pancreatic insufficiency, duodenal byppass,
bile duct obstruction
● Concomitant intestinal & respiratory infections aften result
in poor absorption, utilization – predisposing to VAD

19. Prevention & Control
● Promoting consumption of Vit. A rich food
● Fortification of edible oil
● Administering supplemental dose of Vit.
● Administering measles containing vaccine
● Address concomitant illeness

20. Prevention & Control
● Promoting consumption of Vit. A rich food
● Exclusive breast feeding for 6 months & timely
complimentary feeding. Colustrum must
● Regular consumption of food rich in Vit A, by children ,
pregnant and lactating mothers
● Health education - women visiting anganwadi, ANC, IMM

21. Prevention & Control
● Fortification of edible oil with Vit. A – FSSAI
recommends, also for all toned & double tonned milk
● Administering supplemental dose of Vit. A to all under 5
● 9 months – 100,000 IU
● 18, 24, 30, 36, 42, 48, 54, 60 months – 200,000 IU
● UIP – Vit A every 6 months (6mt – 59 mt), 2MCV

22. Prevention & Control
● Administering measles containing vaccine – 2 doses of
MCV to every eligible child
● Address concomitant illeness like diarrhea, measles etc.
● Treatment – Xerophthalmia responds to Vit A
● 200,000 IU (110mg) of retinol palmitate orally – 2 days
● Infants or < 8kg half dose – 100,000 IU

23. Hypervitaminosis A
● Effects of excessive vitamin A
● Limit of liver stores of retinoid exceeds
● Symptoms-vision problems, skin changes & bone pain.
● Excess vit. A enters circulation causing systemic toxicity
● Β Carotene a precursor of vitamin A, is selectively
converted into retinoids & does not cause toxicity.