rickets.pptx

rickets

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? Vitamin D deficiency- “classical rickets” caused by low endogenous vitamin D 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 2 nd 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 .

9. 3-Pathogenesis of rickets Vitamin D deficiency Absorption of Ca, P Serum Ca Function of Parathyroid

10. 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

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

12. What are the causes of vitamin D deficiency?

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

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

15. Medications Antacids phosphate reduce absorption of calcium and 2) Anticonvulsants ( phenytoin,phenobarbitone ) Lea d t o inc r ease VI T D ca t abol i s m and i n h i b i t c a absorption Corticosteroids Loop diuretics Etiology

16. 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.

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

18. 3-Vitamin D resistant familial hypophosphatemic rickets (X linked dominant.) renal wasting of phosphorus at the proximal tubule level results in hypophosphatemia .

19. C o n t… Clinical features. Early age of onset and severe deformities short stature and sever dental caries Normal ca, PTH, no aminoaciduria .

20. 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

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

22. 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) F r on t al bossing

23. Craniotabes

24. 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

25. Chest deformity Funnel chest – pectus excavatum Pigeon chest

26. 1-Bowlegs and knock-knee 2-enlarged wrist and ankle(double malleoli) Lax ligament- hypotonia 3-extremities

27. Knock knee deformity (genu valgum) Bowleg d e f ormity (genu varum)

28. 3-Investigations 1-Biochemical investigations serum levels of calcium (total and ionized with serum albumin), phosphorus, alkaline phosphatase ( ALP) 4-parathyroid hormone calcidiol urine studies include urinalysis and levels of urinary calcium and phosphorus.

29. 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.

30. 2- Radiological investigation widening of the distal epyphysis fraying and widening of the metaphysis angular deformities of the arm and leg bones.

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

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

33. 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.

34. C o n t … 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 .