Introduction
• Vitamin A deficiency (VAD) is a major
nutritional concern in poor societies,
especially in lower income countries like
INDIA.
• Vitamin A is an essential nutrient needed
in small amounts for the normal
functioning of the visual system, and
maintenance of cell function for growth,
epithelial integrity, red blood cell
production, immunity and reproduction.
VITAMIN A
• Vitamin A is an essential
Micronutrient because it cannot be
biogenerated de novo by animals.It is
obtained from plants in the form
PROVITAMIN A CAROTENOIDS
.
The term Vitamin A refers to all
Trans Retinol, the alcohol form of
• Storage form of vitamin A is
known is RETINAL PALMITATE
• The aldehyde form of Vitamin A is
RETINAL & Functions in VISION.
Physiologically most important
form of Vit A metabolite is the
acid derivetive, RETINOIC ACID
Sources
SOURCES OF VITAMIN A
• The richest sources of Vitamin A
include Oil extracted from Shark &
Cod liver.
• Carrots , Dark green leafy
Vegetables, Squash, Oranges and
Tomatoes are good Sources.
• Infant formulas & many processed
food are fortified with preformed
vitamin A
Sources of Vitamin A
• Breast Milk fulfils the needs of
Vitamin A entirely for the first 6
months of life ,& continues to be a
an important source upto 2 years.
Absorption & Metabolism
• The body acquires Vitamin A
either as preformed Vitamin A
or as Provitamin A carotenoids.
• Vitamin A & Provitamin A are Fat
Soluble & their absorption depend
adequate lipid & protein within
the meal.
ABSORPTION &
METABOLISM
• Vitamin A is absorbed in the
esterified form as a part of
Chylomicrons.
• Absorption is affected by impaired
Chylomicron formation, or when fat
absorption is altererd .
Retinol is absorbed as the free alchol
Absorption & Metabolism
by an active transport system
containing a cellular retinol
binding protein ( CRBP I I.)
The yellow Beta Carotene also
requires Bile salts for absorption
& is converted to Vitamin A in the
intestinal tract. Once absorbed
vitamin A is stored in liver as
RETINAL PALMITATE.
Absorption & Metabolism
• The liver releases Vitamin A to the
circulation , bound to retinol
binding protein (RBP) and to a
pre albumin (Transthyretin)
Absorption & metabolism
Chronic intestinal disoders or Lipid
malabsorption syndromes can
result in Vitamin A deficiency.
STORAGE
• The liver has enormous capacity to
store in the form of RETINOL
PALMITATE.
• under normal conditions a well-fed
person has sufficient Vitamin A
reserves to meet his need for 6 to
9months or more.
Excretion of Vitamin A
• Not readily excreted
• Some lost in urine
• Kidney disease and aging increase risk
of toxicity because excretion is impaired
Recomended daily allowance
• Recommended daily Allowance of
Vitamin A is as follows INFANTS --- 300 -400 micrograms
CHILDREN -- 400 -600 micrograms
ADOLESCENTS – 750 micrograms.
Functions of Vitamin A
• Vitamin A has an essential role in
vision, particularly Night Vision.
• Vitamin A is necessary for
regulation of many genes involved
in cell division & differentiation.
• Many Physiological processes
involving Fetal growth &
development , Reproduction,
Functions Of Vitamin A
Gastrointestinal & respiratory
function , and Immunity are
dependent on vitamin A.
Vitamin A is essential for integrity
of Respiratory Epithelium & Skin.
CARTENOIDS precursors of Vit A
are important Anti Oxidant
defences
Causes of Vitamin A
Deficiency
• SEVERE MALNUTRITION is an
important cause of deficiency.
• The requirement of vtamin A is
increased in PRETERM BABIES &
during INFECTIONS ( eg, Measles
& Respiratory tract infections)
making children prone to
deficiency during these states
Causes of VITAMIN A
deficiency
• CHRONIC DIARRHEA ,
MALABSOPTIVE STATES and
CHRONIC LIVER DISEASES cause
significant Vitamin A deficiency.
Deficiency of Vitamin A
Deficiency of Vitamin A
• In developing countries it is
estimated that 500,000 pre school
children become blind every year
owing to vitamin A deficiency, &
many of them die because of
increased vulnerability to
infections particularly Measles.
Clinical features
• The most characteristic & specific
signs of Vitamin A deficiency are
EYE LESIONS
• Lesions due to Vitamin A
deficiency develop insidiously &
rarely occur before 2 yrs of age.
Clinical features
• Early features : DEFECTIVE DARK
ADAPTATION is the most
characteristic early clinical feature,
resulting in NIGHT BLINDNESS.
PHOTOPHOBIA is a common
symptom observed.
As vitamin A deficiency progresses the
epithelial tissues of the eye
becomes severely altered.
In early vitamin A deficiency Cornea
Keratinizes , becomes opaque , is
susceptible to infections & forms
dry scaly layers of cells , that is
XEROPTHALMIA.
• In later stages, infection occurs ,
lymphocytes infiltrates & cornea
will become wrinkled . It will
degenerate irreversibly ( Known as
KERATOMALACIA) , resulting in
blindness.
• Conjunctiva keratinises & develops
plaques known as BITOTS SPOTS.
• The pigment epithelium is the
structural element of the Retina.
When the pigment epithelium
keratinses & degenerates , Child
will develop BLINDNESS.
EXTRA OCULAR features
• Other clinical features of Vitamin a
deficiency includes POOR
OVERALL GROWTH,
SUSEPTIBILITY TO INFECTIONS,
due to squamous metaplasia of
respiratory, urinary & vaginal tract
epithelium.
DIARRHOEA, ANEAMIA,APATHY
• Mental retardation, increased
intracranial pressure, with wide
separation of intra cranial sutures.
• FOLLICULAR HYPERKERATOSIS
here the skin becomes dry & scaly,
especially over the outer aspect of
the limbs , also known as TOAD
SKIN or PHRYNODERMA.
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
Bitot’s Spot
• These are foamy and
whitish cheese-like tissue
spots that develop
around the eye ball,
causing severe dryness in
the eyes.
• These spots do not affect
eye sight in the day light.
Conjunctival Xerosis
• Conjunctiva becomes
dry and non wettable.
• Instead of looking
smooth shiny it
appears muddy
&wrinkled.
Keratomalacia
• One of the major cause
for blindness in India.
• Cornea becomes soft
and may burst
• The process is rapid
• If the eye collapses
vision is lost.
Follicular hyperkeratosis
DIAGNOSIS
• In the presence of clinical
manifestations , diagnosis is not
difficult.
• SERUM RETINOL LEVEL usually
below 20 mg/dl in Vitamin A
deficiency .
• CONJUNCTIVAL IMPRESSION
CYTOLOGY is a noninvasive
technique that asseses Vit A status
TREATMENT
• PREVENTION of Vitamin A
deficiency can be achieved by
making available the
recommended daily allowances to
all children.
• AS per the NATIONAL
PROGRAM for prevention
BLINDNESSS , the children in age
group of 6 to 11 months should
Should receive 100,000 I.U of
Vitamin A Orally (preferably
during Measles immunization) &
other children between 1 & 5 years
should receive 200,000 I.U vitamin
A every 6 months, in target areas.
• Use of Vit A & beta carotene rich
food should be encouraged.
• Infants 6 to 12 months recive a half
dose & infants less than 6months
one quarter the dose, following
the same schedule.
• Children with pneumonia,
wasting malnutrition ,recurrent
diarrhoea, & severe infections
should also recieve full treatment
course of vitamin A
• Fortification of commonly eaten
foods with vitamin A can be an
effective prophylactic measure.
• Treatment of XEROPTHALMIA –
200,000 IU vitamin A should be
given orally on presentation, the
following day& whenever possible,
0ne to four weeks later.
Recommended Xerophthalmia
treatment schedule
6 -12 months
• Immediately 100,000 IU
• Next day
100,000 IU
• 2–4 weeks later 100,000 IU
> 1 yr
200,000 IU
200,000 lU
200,000 IU
• Severe Protein-Energy Malnutrition (PEM)
Monthly until PEM resolves
100,000 IU
200,000 IU
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Hypervitaminosis A
Toxcity may appear with massive
doses or with large doses taken
over a large time period.
Clinical features : child may have
Nausea, Vomiting, Drowsiness,
pappilledema, & symptoms
suggestive of raised intracranial
tension (PSEUDOTUMOR
CEREBRI) .
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• Chronic cases may show marked
Anorexia, failure to thrive,
Alopecia, seborrheic dermatitis,
Hepatomegaly, & tender bone
swelling may develop.
• RADILOGICALLY May show
Hyperosteosis of the shafts of long
bones.
• Beta carotene ingestion is
seemingly without toxicity , with
chronic high consumption stains
the skin yellow –orange which is
benign & reversible.
MCQ
• 1)Which of the following is not a
rich source of Vitamin A?
• A) Shark liver oil
• B) Green leafy Vegetables
• C) Sun flower oil
• D) Oranges & Tomatoes
• 2) Daily Recommended Vitamin D
requirement in Infants
• A) 100 -200 micrograms
• B) 300-400 micrograms
• C) 50 micrograms
• 3) VITAMIN A is not needed for
which of the following functions?
A) Night vision
B) Immunity
C) Functioning of Thyroid Gland
D) Reproduction
• 4) Bitots spots are seen in the
• A) Skin
• B) Conjunctiva
• C) Cornea
• D) Fundus
• 5) Vitamin A is Usually given to
the infant during
• 1) Pulse polio immunisation.
• 2) Measles immunisation
• 3) BCG Immunisation
• Write Short Notes on
• 1) Functions of Vitamin A
• 2) Ocular Manifestations Of
Vitamin A deficiency.
• 3) Hypervitaminosis A
• 4) Treatment of Xeropthalmia
• Major Question
• 1)Clinical features Of Vitamin A
deficiency And Its Management
• 2) WHO Classification for
Xeropthalmia . Explain Treatment
of Xeropthalmia.
Thanking You