vitamin D deficiency

1. Resource Person:-Prof.Dr.A.K.Dutta
Presented by:- Prateek Singh

2. Vitamin D is a
group of fat-soluble
prohormones.


Two
major forms of
which are vitamin D
2
(or ergocalciferol)
and vitamin D
3
(or
cholecalciferol).
Produced in skin
exposed to sunlight,
specifically
ultraviolet B
radiation.
Production is greatest in the
stratum basale and stratum
spinosum .

3. Functions of Vitamin D
Regulates the calcium and phosphorus levels
in the blood by promoting their absorption
from food in the intestines.
Promotes bone formation and
mineralization .
Inhibits parathyroid hormone secretion
from the parathyroid gland.
Affects the immune system by promoting
immunosuppression, phagocytosis, and
anti-tumor activity

4. Dietary sources of
vitamin-D
Fortified foods especially
dairy products, cereals and
vit. Supplements.
Fish, liver, oils, egg yolk &
butter.
Infants: obtain vit D
supplement from mothers
milk, infant formulas, cow
milk .

5. Why Vitamin D deficiency
occurs?
Due to:-
Inadequate sunlight exposure.
Poor access to micronutrients rich
food.
Disorder that limit its absorption.
Deficient soil quality.
Impaired conversion into active
metabolites.
Possible role of dietary fibers.

6. These lead to:-
Learning disability
Impaired work capacity.
Increased susceptibility to infection

7. Deficiency causes:-
In children:-
RICKETS:- Bone softening diz., deformity
of long bones occur.
In adults:-
OSTEOMALACIA:- Bone thinning
disorder,proximal
muscle weakness & bone fragility.
OSTEOPOROSIS:-Decrease bone
minerilzation & inc. Bone fragility.

8. RICKETS:-
Rickets is characterized by
bone deformities
due to incomplete
mineralization, resulting
in soft & pliable bones and
delay in teeth
formation.
The weight bearing bones
are bent to form bow
legs

9. Risk factors
 Breast-fed infants whose mothers are
not exposed to sunlight .
Breast-fed infants who are not exposed to
sunlight .
 Lactose intolerant.
Individuals with red hair have a decreased
risk for rickets due to their greater
production of vitamin D in sunlight.

10. In supply of 1,25 dihydroxy vit D
Absence of adequate stores
Intestinal absorption of Ca & P
Release of parathyroid hormone
25(OH) vit D
Pathogenesis of Rickets
Appears to develop in 3 stages:-
1
s t
stage

Absorption of Ca & P
Mobilization of Ca & P
from bone
1,25 (OH)
2
vit D
3
(in kidney)

11. 2
n d
stage:-
Relative Hyperparathyroidism
Phosphaturia
Negative phosphorus balance
Hypophosphatemia

12. 3
r d
stage:-
Relative hyperparathyroidism
Depleted 25(OH) vit D
Impaired production of
Adequate quantity of 1,25(OH)
2
vit D
3
Intestinal absorption of Ca & P

13. Signs and Symptoms
Bone pain or tenderness.
musclemuscle weakness ( weakness (rickety rickety
myopathymyopathy or "floppy baby or "floppy baby
syndromesyndrome")
Increased tendency for
fractures (easily broken
bones), especially
greenstick fractures
Hypocalcemia
Tetany
Craniotabes (soft skull)
Skeletal deformity:Cranial,
spinal, and pelvic
deformities

14. Bowed legs (genu varum)

Knock-knees (genu valgum) or
"windswept knees.
Costochondral swelling
( "rickety rosary" or "rachitic
rosary")
Harison’s sulcus and pot belly

15. Diagnosis:

16. Treatment:-
Natural & artificial light are effective
therapeutically but oral administration
preferred.
Administration of 15,000ugm or 6,00,000
IU of vit.D
3
orally or I.M. induces rapid
healing.
If healing lines of rickets is not seen on x-
ray plate of bone within 3-4 weeks of
therapy, the above dose may be repeated .
Cases who respond to this therapy are further
put on 400 units or 10ugm of vitamin D
3 per
day after the process of healing has started.

17. Requirement
Body needs are met entirely by
conversion of 7 dehydrocholesterol to
vit D
3
in skin
Or
 in absence of exposure to UV light,
it can be met entirely by ingestion
of Vit D
The recommended dietary intake for
vit D by infants has been accepted
as 200IU/day
and children 400IU/day

18. Hypervitaminosis – D
Signs & symptoms - similar to idiopathic
hypercalcemia.
Symptoms include:-
Hypotonia, anorexia, irritability,
constipation,
 polyuria, pallor
Aortic stenosis, vomiting
Hypertension
Retinopathy
Urine shows proteinuria
Metastatic calcification as revealed by x-
rays
Generalized osteoporosis
T/t includes discontinuation of vit D &
intake of calcium

19. References :-
Essential Pediatrics by O . P . Ghai
Textbook of Preventive & social medicine by K .
Park
www.mc.vanderbilt.edu

20. THANK YOU