Rickets

Question 1

What is rickets?

Answer 1

The failure to mineralize newly formed bone

Question 2

What are the causes of rickets?

Answer 2

1. Lack of vitamin D

2. Lack of phosphate and calcium

Question 3

Why does rickets occur more in infants?

Answer 3

Because it characteristically manifests during periods of rapid growth which occurs during infancy or adolescent growth spurts

Question 4

What are the clinical features of rickets?

Answer 4

1. Long bone deformities- genu valgus ad genu Varys, windswept appearance
2. Delayed closure of the fontanelles
3. Rickety rosary(enlarged costochondrial joints)
4. Widened metaphyses(ankles and wrists)
5. Harrisons sulcus
6. Craniotabes

Question 5

What are the clinical signs of hypocalcaemia?

Answer 5

1. Convulsions
2. Apneoic attacks
3. Laryngospasm

Question 6

What are the clinical signs of muscle weakness?

Answer 6

1. Hypotonia
2. Delayed motor milestones
3. Prominent abdomen

Question 7

What specific test would we do in rickets?

Answer 7

1. Serum calcium, phosphate, parathyroid hormone, 25OHD

Question 8

What is on your differential diagnosis if it is not rickets?

Answer 8

1. Osteogenesis imperfecta
2. Healed rickets
3. Metaphyseal dysplasia

Question 9

What are the pre-disposing factors to getting rickets in young infants?

Answer 9

1. Darker skin
2. Covering up skin
3. Vegetarian diets
4. Prolonged breast feeding with no vitamin D supplementation
5. Babies born to vitamin d deficient moms

Question 10

How is vitamin D metabolized?

Answer 10

1. It comes in two forms. From the skin(cholecalciferol) and from the diet(ergocalciferol)
2. It is then stored in the GIT tract or the muscle or transported in the liver where it becomes 25OH
3. It is then transported to the kidney where phosphate or PTH hydroxyulate it to 1,25OH2D

Question 11

What are the causes of rickets divided into?

Answer 11

1. Calcium deficiency rickets

2. Phosphorous deficiency rickets

Question 12

What are the causes of calcium deficient rickets?

Answer 12

1. Decreased vitamin D intake
   - diet or sunlight
2. Decreased Vitamin D absorption
   - biliary atresia, coelioc disease
3. Impaired hydroxylation of vitamin D to 25OH
4. Decreased synthesis of 1,25dihydroxy vitamin D
   - renal failure
5. Increased metabolism due to drugs like anti-convulsants

Question 13

What are the causes of phosphorous deficiency rickets?

Answer 13

1. Decreased intake of phosphate
   - prematurity
2. Decreased intestinal absorption
   - ingesting aluminum hydroxide
3. Increased renal losses
   - Franconi’s syndrome