Rickets is a childhood bone disease caused by vitamin D deficiency and impaired bone mineralization. The main types are nutritional rickets from inadequate vitamin D, calcium, or phosphate intake and vitamin D-dependent rickets caused by genetic defects. Physical exam findings include bone tenderness, bowed legs, and chest deformities. Laboratory tests show low calcium, phosphate, and vitamin D levels with elevated alkaline phosphatase and parathyroid hormone. X-rays demonstrate widened growth plates and fraying of bone. Treatment involves high dose vitamin D supplementation with calcium and phosphate as needed.

1. Approach to a child
with Rickets

2. Definition of Rickets. .
Types of rickets and how to differentiate
between them biochemically
Causes of rickets
Vitamin D metabolism.
Outline

3. What is Rickets?
•Rickets is a disease of growing bones due to
defective mineralization at growth plates in
growing children.
• (Osteomalacia is the same condition in adults)
• Adequate calcium and phosphate levels
are required for bone mineralization and vitamin
D is critical for calcium homeostasis

4. What are the different types of
rickets?
a)Vitamin D deficiency- “classical rickets”
caused by low endogenous vitamin D
b) Vitamin D dependent-
• type 1 is due to 1 alpha hydroxylase deficiency
• type 2 is due to a mutation in the vitamin D
receptor
c) Vitamin D resistant- defect in tubular
reabsorption of phosphate

5. 1- Nutritional
• Nutritional rickets results from inadequate
sunlight exposure or inadequate intake of
dietary vitamin D, calcium, or phosphorus.
• Mostly onset is at the end of the first or during
the 2nd year.
In children, vitamin D deficiency is the most
common cause of rickets

6. Vitamin D Sources
• Sun light exposure
• Diet ( liver and egg yolks )

7. Cholecalciferol (vitamin D-3) is formed in the skin from
7-dihydrotachysterol. This steroid undergoes hydroxylation in 2 steps.
Pathophysiology - Metabolism of vitamin D
• The first hydroxylation occurs at position 25 in the liver, producing
calcidiol (25-hydroxycholecalciferol), which circulates in the plasma as
the most abundant of the vitamin D metabolites
• is a good indicator of overall vitamin D status.

8. Cont.........
• The second hydroxylation step occurs in the kidney at the 1 position,
where it undergoes hydroxylation to the active metabolite calcitriol
(1,25-dihydroxycholecalciferol - DHC). This cholecalciferol is not a
vitamin, but a hormone.

10. 3-Pathogenesis of rickets
Vitamin D deficiency
Absorption of Ca, P
Serum Ca
Function of Parathyroid

11. Pathogenesis
PTH
High secretion
P in urine Decalcification of old bone
P in blood Ca in blood normal or low slightly
Ca, P product
Rickets

12. There are three stages of vitamin D
deficiency:
1. Hypocalcaemia due to poor intestinal
absorption and reduced bone resorption.
2. Normal calcium and low phosphate state due
to secondary hyperparathyroidism
3. Severe bone disease with recurrence of
hypocalcaemia.

13. • What are the causes of vitamin D
deficiency?

14. 1poor exposure to sunlight
2- dark skin ( black children)
3-. Improper feeding:
1) Inadequate intake of Vitamin D
• Breast milk
• Cow’s milk
0-10IU/100ml
0.3-4IU/100ml.
2) Improper Ca and P ratio
Etiology

15. 3. Fast growth, increased requirement (relative
deficiency)
4. Diseases ( malabsorption)
 Liver diseases, renal diseases
Gastrointestinal diseases (Celiac disease, pancreatitis )
Cystic fibrosis
Etiology

16. • Medications
1) Antacids
phosphate
reduce absorption of calcium and
2) Anticonvulsants ( phenytoin,phenobarbitone )
Lead to increase VIT D catabolism and inhibit ca
absorption
1) Corticosteroids
2) Loop diuretics
Etiology

17. 2-Vitamin D dependent
• Vitamin D-dependent rickets, type I
• is secondary to a defect in the gene that codes for
the production of renal 25(OH)D3-1-alpha-
hydroxylase.
Different from simple rickets
1- early onset- 3-6 month
2- history of adequate intake of vitD and sun exposure
3-normal 25 hydroy vit D but low 1,25 dihydroxy D3.

18. Vitamin D-dependent rickets, type II
1. is a rare autosomal disorder caused by
mutations in the vitamin D receptor.
2. elevated levels of circulating calcitriol
differentiate this type from type I.
3. Generalized alopecia occur in 50% of the
cases .

19. 3-Vitamin D resistant
1familial hypophosphatemic rickets
(X linked dominant.)
2 renal wasting of phosphorus at the
proximal tubule level results in
hypophosphatemia.

20. Cont…
• Clinical features.
1 Early age of onset and severe
deformities
2 short stature and sever dental
caries
3 Normal ca, PTH, no aminoaciduria .

21. Type Biochemical feature
Nutritional rickets N/low ca
N/low p
AP and PTH high
Low 25 VIT D
Normal 1,25 VIT D
VIT D DEP TYPE 1 Low CA
N/low p
AP and PTH high
Normal 25 VIT D
LOW 1,25 VIT
Type 2 Low CA
N/low p
AP and PTH high
Normal 25 VIT D
high 1,25 VIT
Vitamin D resistance Normal CA , normal PTH , normal 25 VIT D
Low phosphate

22. 1complete physical and
dental examinations should
be performed.
2The entire skeletal system
must be palpated to search
for tenderness and bony
abnormalities.
3 Gait disturbances
and neurologi abnormalities
(such as hyperreflexia) in all
children should be sought
2-Physical examination

23. 1-head
• 1-Craniotabes manifests
early in infants
• 2-frontal bossing and
delays the closure of the
anterior fontanelle.
• 3-Increased incidence of
cavities in the teeth
(dental caries)
Frontal bossing

24. Craniotabes

25. 1-rachitic rosary
2-Pigeon chest
3- The weakened ribs
pulled by muscles also
produce flaring over the
diaphragm, which is
known as Harrison
groove.
Rib beading
(rachitic rosary)
2-Thorax

26. Chest deformity
Funnel chest – pectus excavatum
Pigeon chest

27. • 1-Bowlegs and
knock-knee
• 2-enlarged wrist
and ankle(double
malleoli)
• Lax ligament-
hypotonia
3-extremities

28. Knock knee deformity
(genu valgum)
Bowleg deformity
(genu varum)

30. 3-Investigations
1-Biochemical investigations
1 serum levels of calcium (total and ionized
with serum albumin),
2 phosphorus,
3alkaline phosphatase (ALP)
4-parathyroid hormone
5 calcidiol
6 urine studies include urinalysis and levels of
urinary calcium and phosphorus.

31. Decreases
in serum calcium,
serum phosphorus,
calcidiol, calcitriol,
urinary calcium.
The most common laboratory findings in
nutritional rickets are:
Parathyroid hormone,
alkaline phosphatase,
urinary phosphorus
levels are elevated.

32. 2- Radiological investigation
widening of the distal epyphysis
fraying and widening of the metaphysis
angular deformities of the arm and leg
bones.

33. Classic radiographic findings include
Show cupping and fraying of the metaphyseal region

34. • Classic radiographic findings include:
Radiographs of the knee of a 3-year-old girl with hypophosphatemia
depict severe fraying of the metaphysis.

35. 4-Treatment
1. Special therapy: Vitamin D therapy
• A. General method: Vitamin D 2000-4000 IU/day
for 2-4 weeks, then change to
preventive dosage – 400 IU.
• B. A single large dose: For severe case, or Rickets with
complication, or those who can’t bear oral therapy.
Vitamin D3 200000 – 300000 IU, im,
preventive dosage will be used after 2-3 months.

36. Cont…
2-. Calcium supplementation: Dosage: 1-3
g/day
• only used for special cases, such as baby fed
mainly with cereal or infants under 3 months
of age and those who have already
developed tetany.
3-. Plastic therapy:
In children with bone deformities after 4
years old plastic surgery may be useful.