52 MSK Manifestations of Systemic Disease

Question 1

T/F Rickets only affects children

Answer 1

T

Question 2

Causes of rickets can be classified as either ___ or ___

Answer 2

1) Calcipenic
2) Osteopenic

Question 3

Calcipenic rickets is mostly due to

Answer 3

1) Deficiency of the active form of Vitamin D (1,25-dihydroxyvitamin D3)
2) Calcium deficiency

Question 4

Celiac disease, IBD, scleroderma, and liver disease can cause rickets due to

Answer 4

Impaired calcium absorption

Question 4

Phosphopenic rickets is mostly due to

Answer 4

Renal wasting ofphosphate

Question 5

Underlying biochemical abnormality in Vitamin D resistance resulting in rickets

Answer 5

Impaired parathormone-dependent proximal renal tubular reabsorption of phosphate

Question 6

Underlying biochemical abnormality in Type 1 Vitamin D dependence

Answer 6

Defect in renal 1-α-hydroxylase

Question 7

Underlying biochemical abnormality in Type 2 Vitamin D dependence

Answer 7

End-organ unresponsiveness to 1,25-dihydroxyvitamin D3

Question 8

Underlying biochemical abnormality in hypophosphatasia

Answer 8

Decreased serum ALP

Question 9

MC causes of rickets worldwide

Answer 9

1) Exclusion from the sun for social/cultural reasons
2) Insufficient dietary intake of vitamin D

Question 10

T/F Rickets is uncommon in dark-skinned children living in colder climates

Answer 10

F, more common

Question 11

Cause of rickets in developed countries despite adequate vitamin D intake

Answer 11

Impaired absorption because of GI problems

Question 12

T/F Vitamin D insufficiency in infants can be compounded by breastfeeding

Answer 12

T

Question 13

Group of medications that may interfere with Vitamin D metabolism

Answer 13

Anticonvulsant medications

Question 14

Normal source of vitamin D3 in humans

Answer 14

Skin

Question 15

Cause of rickets exemplified by accumulation of cystine in different organs and tissues leading to severe organ dysfunction (RTA in the kidneys) and CKD

Answer 15

Cystinosis

Question 16

Typical radiographic finding in rickets

Answer 16

Metaphyseal resorption

Question 17

Coverted in the skin to previtamin D3 (prohormone) by sunlight

Answer 17

7-dehydrocholesterol

Question 18

Protein that carries vitamin D3 and vitamin D2 to the liver

Answer 18

DBP (vitamin D-binding protein)

Question 19

Transforms provitamin D3 in the liver

Answer 19

Vitamin D-25-hydroxylase&raquo_space; 25(OH)D

Question 20

Transforms 25(OH)D in the kidney

Answer 20

25(OH)Dα-hydroxylase&raquo_space; 1,25-di(OH)D

Question 21

Dx: Infant with short stature, bowing of legs, ectopic calcification, low serum phosphate with normal calcium level

Answer 21

Hypophosphatemic vitamin D-resistant rickets

Question 22

In Type I vit D-dependent rickets, typical features of disease usually occurs at

Answer 22

Before 2 years of age

Question 23

In Type II vit D-dependent rickets, typical features of disease usually occurs at

Answer 23

Early infancy

Question 24

Dx: Features of rickets, alopecia, absence of eyelashes