Vitamin A

1. VITAMIN A
• Soumya Ranjan Parida
• Basic B.Sc. Nursing 4th
year
• Sum Nursing College

2. Introduction
• Necessory nutrient
• Present mostly in animal tissues.
• Vita. A deficiency is most common cause of
blindness that is preventable (may be
irreversible)
• About 10000 childern/yr become blind in
india due to deficiency

3. Physiology
• Vitamin A is sub gp of retinoids
Retinol - vita A alcohol
Retinyl ester - vita A ester
Retinal - vita A aldehyde
Retinoic acid - vita A acid (most active
form)

4. Physiology
• Beta-carotene- provitamin A
• Found in vegetables.
• Converted in retinol in intestinal wall.
• Retinol & carotene both are fat soluble.
• Stored in liver as retinyl palmitate.
• Retinol is transported in blood,bound to
retinol binding protein(RBP).

5. sources
• Retinol-
Rich – cod liver oil,shark liver oil & liver
Moderate- butter, ghee, egg yolk
• Carotene-
Best- red palm oil
Good- carrots, green leafy & yellow red
vegetables,ripe mangoes, papaya .

6. Functions of vita A
1. Necessory for dim light vision.
• The mojor difference between visual pigment in
Rods (Rhodopsin) & Cones (Iodopsin) is nature of
the protein bound to retinol.
• In dark –11-trans retinol covert in 11-cis form by
the help of enzyme retinene isomerese which then
combines with opsin to form rhodopsin.This
process is vita.A dependent.so patients with
vita.A deficiency have delayed dark adaptation.

7. 2. vita.A is necessory for membrane
stability. Its deficiency as well as excess
causes rupture of lysosomal membranes.
3. play a role in keratinization, cornification
& mucous formation.
4. Deficiency causes basal cell proliferation
hyperkeratosis & stratified sqamous
epithelium formation in respiratory, urinary
& other organs which causes increased
incidence of infection in these areas.

8. 5. Retinol enhance the humoral immune
response.beta-carotine has got antioxident
property.
6.role in retinitis pigmentosa &protoporphyria
7.In experimental animals it decreases the
incidence of epithelial tumors.
8.deficiency also causes loss of appetite, loss
of weight, eye lesions, disruption of
reproductive process.

9. Clinical features
• Ocular
1.Night blindness
2.Conjuctival xerosis- dryness, loss of
transperancy,thicking, wrinkling,
pigmentation, acumulation of debris.
3. Bitot’s spot – small plaque with silvery
grey hue & foamy surface, triangular,raised
surface, in bulbar conjectiva usually near
limbus on temporal side.

10. Clinical feature:cotinue….
• 4.Corneal xerosis
• 5. Corneal ulceration
• 6. Kertomalacia – rapid & characterstic
softening of a part or whole of cornea.

11. WHO classification of
Xerophthalmia
• Primary signs
X1A-Conjuctival xerosis
X1B-Bitot’s spots
X2-Corneal xerosis
X3A-Corneal ulceration
(<1/3 of cornea)
X3B-Corneal ulceration
(> 1/3 of cornea)
• Secondary signs
XN-Night blindness
XF-Fundal changes
XS-Corneal scarring

12. Other menifestations
• Retardation of mental & physical growth.
• Apathy
• Anaemia
• Hepatosplenomegaly
• Dry, scaly & hyperkeratosis of skin.
• Pyuria or hematuria.
• Raised ICT
• Hydrocephalus with or without cranial
nerve palsy

13. Causes of deficiency
• Age- young children & males
• Absorption defects- fat malabsorption,
cystic fibrosis
• Disorders of metabolism- diabetes
mellitus, enzyme deficiency
• Cirrhosis, hepatitis, thyrotoxicosis
• Poor intake of vita.A,low fat diet
• Enviormental factors-drought,femine
• Infection & infestations

14. Treatment
• VITAMIN A (oral)
50,000 iu- age < 6 months
1 lac iu- age 6-12 months
2 lac iu- age > 1 year
On 1st
day ,next day and 4 weeks later .
• Parentral,water soluble vita.A given in ½ or
¾ of oral if impaired oral intake, persistant
vomiting & severe malabsobtion
• Symptomatic treatment of associated
condition to be given.

15. Prevention
• Nutritional & dietory education to mothers.
• 1 lac IU vita.A to infant at 9 month of age with
measles vaccine & 2 lac IU at 18,24, 30 ,36 month
of age.
• Prompt treatment & periodic follow up of
children.
• Recommended intake 300-400 microgram daily
• Periodic deworming.

16. Hypervitaminosis A
• ACUTE- ingestion of 3 lac IU or more
• Nausea, vomiting, drowsiness, buldging of
fontanella, diplopia, papilledema & other
symp. Suggest brain tumor.
• CHRONIC- ingestion of excessive doses
for several weeks & months.
• Anorexia, pruritus & lack of weight gain,
long bones may show hyperosteosis.

17. THANKS