Metabolic Diseases Of Bone

Question 1

Causes of Rickets

Answer 1

1. Vit D deficiency: M/C cause
   > Nutritional (M/C cause)
   > Malabsorption
   > Lack of sunlight exposure
   > Liver and kidney disease
   > Drugs
2. Ca 2+ deficiency
3. PO4 3- deficiency

Question 2

Labs of Rickets
Just study

Answer 2

1. Ca 2+: Dec/Normal (Early disease)
2. Increased:
   > PTH
   > ALP
3. Decreased:
   > PO4 3-

Question 3

Skull changes in Rickets

Answer 3

1. Craniotabes/softening of skull/ping pong skull: Earliest
2. Frontal bossing
3. Delayed closure of fontanelle

Question 4

Chest changes of Rickets

Answer 4

1. Rachitic rosary: Costochondral junction swelling (Blunt and non-tender)
2. Pigeon chest/pectus carinatum: Prominent sternum
3. Harrison sulcus: D/t bending of softened ribs by diaphragm contraction

Question 5

Long bone deformities in Rickets

Answer 5

Bowing of legs
Only seen once child starts weight bearing
Not seen in infants

Question 6

Hip joint changes in Rickets

Answer 6

Coxa vara (Proximal femur)
Diff types of deformities:
1. B/L genu varum (M/C)
2. B/L genu valgus
3. Windswept deformity:
> Children/Overall -> Rickets (M/C)
> Adults -> RA (M/C)

Question 7

Radiological features of Rickets

Answer 7

1. Fraying-ragged edges
2. Cupping of Metaphysis
3. Splaying of Metaphysis
4. Widening of epiphyseal plates
5. White line of Frankel: Mineralisation of growth plate

Question 8

C/F of Osteomalacia

Answer 8

1. Polyarthralgia
2. Bone pains
3. Proximal myopathy

Question 9

What are Looser zones?

Answer 9

Stress # that have healed with mineral deficit material

Question 10

Investigations of Osteomalacia

Answer 10

X ray:
1. Pseudo fractures: AKA Milkman’s line/looser zone
> M/C site: Neck of femur, clavicle, ribs, pubic rami
2. Protrusio acetabuli: Head of femur protrudes into acetabulum

Question 11

Treatment of Osteomalacia

Answer 11

Vit D:
1. Stoss regimen: 3 lakhs- 6 lakhs IU deep IM/oral (stat or over 1-5 days)
2. Daily: 2K - 5K for 4-6 weeks
3. Weekly: 50K-60K for 8-12 weeks

Question 12

What is Scurvy?

Answer 12

Defect in collagen maturation of osteoid
D/t def of vit C

Question 13

C/F of Scurvy

Answer 13

1. Costochondral junction: Scorbutic rosary
2. Bleeding gums
3. Easy bruising
4. Bone: Subperiosteal hemorrhage -> B/L knee pain

Question 14

Radiological features of Scurvy

Answer 14

Diaphysis:
1. Ground glass appearance
2. Pencil thin cortex
Metaphysis:
1. White line of Frankel
2. Scorbutic zone
3. Pelkan’s spur
Epiphysis:
Wimberger ring sign

Question 15

Treatment of Scurvy

Answer 15

Vit C supplementation

Question 16

Pathophysiology of Primary hyperparathyroidism

Answer 16

Inc in PTH -> Inc in Ca 2+ (Despite -ve feedback)

Question 17

Lab findings of Primary hyperparathyroidism

Answer 17

1. Inc in Ca 2+
2. Inc in PTH
3. Dec in PO4 3-
4. Inc in ALP

Question 18

C/F of Primary hyperparathyroidism

Answer 18

D/t excess bone breakdown:
Inc in PTH -> Inc in bone resorption
1. Teeth: Resorption of lamina dura
2. Salt and pepper skull
3. Phalanges: Subperiosteal resorption on radial side
4. Bone: Brown tumor

Question 19

Brown tumor leads to

Answer 19

Brown tumor -> Breakdown of bone -> Cavities formed -> Filled with blood -> Hb breaks down to hemosiderin

Question 20

Effects of inc in S.Ca 2+

Answer 20

Bones, stones, groans, psychiatric overtones, fatigue

Question 21

What is Renal osteodystrophy?

Answer 21

D/t complication of CKD
Characterized by changes in bone structures and mineralization d/t abnormalities in Ca, PO4, vit D metabolism

Question 22

X ray of Renal osteodystrophy

Answer 22

Rugger Jersey spine (Also seen in osteopetrosis)

Question 23

Lab values of Renal osteodystrophy

Answer 23

1. Dec in Ca 2+
2. Inc in:
   > Phosphate
   > PTH
   > ALP

Question 24

What is Osteoporosis?

Answer 24

Quantitative defect: Porous bone disease (Normal lab values)

Question 25

Pathogenesis of Osteoporosis

Answer 25

Aging -> Imbalance b/w osteoblast and osteoclast (Bone formation < Resorption) -> Dec in strength of bone -> Weak bones and microfractures

Question 26

Types of Osteoporosis

Answer 26

Primary and Secondary

Question 27

Primary osteoporosis Just study

Answer 27

Type I: Post menopausal (M/C risk factor) Type II: Senile (M/C cause)

Question 28

Secondary osteoporosis is caused by

Answer 28

1. Drugs: > Steroids > Heparin 2. Hormones: Cushing’s 3. Immobilisation 4. Weightlessness/space 5. Rheu arthritis

Question 29

What is Kyphosis?

Answer 29

Forward bending of spine

Question 30

C/F of Osteoporosis

Answer 30

1. Back pain: Earliest (Pain before fracture: Constant weight bearing) 2. Fragility fracture: > M/C complication > Sites: Spine, neck of femur/hip, Colle’s # 3. Deformity: Kyphosis

Question 31

Investigations of Osteoporosis

Answer 31

IOC: Bone mineral density scan Performed using DEXA Assess spine, hip, calcaneus T-score: Bone mineral density compared to young male/female (30 y) highest density

Question 32

T score Just study

Answer 32

0 to -1: Normal -1 to -2.5: Osteopenia <= -2.5: Osteoporosis < -2.5 with fracture: Severe osteoporosis

Question 33

Screening in Osteoporosis Just study

Answer 33

1. Women >= 65 yrs 2. Men >= 70 yrs 3. Fracture with trivial trauma > 50 years

Question 34

Treatment of Osteoporosis if inc in bone formation

Answer 34

1. Teriparatide (rPTH): Small doses (Inc in risk of osteosarcoma) 2. Abaloparatide (PTHrp) 3. Romosozumab

Question 35

Treatment of Osteoporosis that does both works

Answer 35

Strontium ranelate

Question 36

Treatment of Osteoporosis if dec in bone resorption

Answer 36

1. Bisphosphonates (DOC) 2. Denosumab 3. SERM: Raloxifene 4. HRT for post-menopausal women

Question 37

M/C vertebral # in Osteoporosis

Answer 37

Lower thoracic and upper lumbar

Question 38

Drug holiday of Bisphosphonates

Answer 38

Temporarily stop using Bisphosphonates (1-2 years) and switch to other drugs (Teriparatide) This is d/t atypical fractures around hip d/t prolonged use

Question 39

C/F of Paget’s disease

Answer 39

AKA Osteitis deformans 1. Pain 2. Bone is worm to touch and thickened/irregular 3. Weak bone (Banana fracture) 4. Cranial Foramen stenosis: CN 2,5,7,8 (Hearing disturbances) 5. Otosclerosis 6. Thickening of skull: Frequent changes in hat size

Question 40

Pathophysiology of Paget’s ds

Answer 40

1. Lytic phase: Osteolytic activity 2. Mixed phase: Both osteolytic and osteoblastic activity 3. Blastic phase: Osteoblastic activity

Question 41

Etiology of Paget’s ds

Answer 41

1. Idiopathic (M/C) 2. SQSTMI gene mutation 3. Paramyxovirus 4. Inc in ALP: 10x to 100x 5. S. Ca 2+: Normal 6. S. PO4 3-: Normal

Question 42

Radiological features in Lytic phase

Answer 42

1. Blade of grass/Flame shaped appearance 2. Osteoporosis circumscripta: Circumscribed lesion in skull

Question 43

Radiological features of Blastic phase

Answer 43

Thickening of skull (Tam o’ Shanter skull)

Question 44

Treatment of Paget’s ds

Answer 44

Zolendronate: 1. Long acting Bisphosphonate 2. Suppress osteoclastic activity

Question 45

Radiological features of Mixed phase

Answer 45

1. Picture frame vertebrae (Sclerosis at edges) 2. Ivory vertebrae 3. Cotton wool skull

Question 46

Complications of Paget’s ds

Answer 46

1. High output cardiac failure (Causes death) 2. Transformation to osteosarcoma

Question 47

What is Osteogenesis imperfecta?

Answer 47

Genetically abnormal collagen COLA 1 gene defect

Question 48

C/F of Osteogenesis imperfecta

Answer 48

1. Deformities: D/t multiple fractures in same bone 2. Blue sclera 3. Easy bruising 4. Multiple fractures in different stages of healing 5. Delayed dentition

Question 49

Pathophysiology of Osteopetrosis

Answer 49

AKA Marble bone disease Dec in Osteoclast function -> Dec in resorption -> Inc in bone formation -> Medullary cavity obliterated by bone

Question 50

C/F of Osteopetrosis

Answer 50

1. Excessive thickened bone 2. Aplastic anemia 3. Multiple infections