Vitamin D is a group of fat-soluble prohormones that are mainly produced in the skin upon exposure to sunlight. It regulates calcium and phosphorus levels in the blood and promotes bone formation. Vitamin D deficiency can cause rickets in children, characterized by soft and weak bones and bone deformities, and osteomalacia in adults, which is the softening of bones. Risk factors include inadequate sunlight exposure, poor nutrition, and disorders inhibiting absorption. Treatment involves oral or injectable high-dose vitamin D to promote healing.

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 D2
(or ergocalciferol)
and vitamin D3 (or
cholecalciferol).
Produced in skin
exposed to sunlight,
specifically
 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:-
 1st
stage
Absorption of Ca & P Mobilization of Ca & P
from bone
1,25 (OH)2 vit D3
(in kidney)

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

12.  3rd
stage:-
Relative hyperparathyroidism
Depleted 25(OH) vit D
Impaired production of
Adequate quantity of 1,25(OH)2 vit D3
Intestinal absorption of Ca & P

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

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.D3 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 D3 per

17. Requirement
 Body needs are met entirely by
conversion of 7 dehydrocholesterol to
vit D3 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 &

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

20. THANK YOU