Bone Formation And Bone Diseases

Front 1

What type of ossification do bones of axial skeleton, appendicular skeleton and base of skull have?

Back 1

Endochondral Ossification

Front 2

What is Endochondral Ossification?

Back 2

Cartilaginous model of bone is first made by chondrocytes → osteoclast/osteoblast later replace with woven bone and then remodel to lamellar bone

Front 3

In adults, what type of bone occurs after fractures? In what disease we can see this?

Back 3

Woven Bone.

In Paget disease of bone.

Front 4

What type of ossification is defective in Achondroplasia?

Back 4

Endochondral Ossification

Front 5

What type of ossification do bones of calvarium and facial bones have?

Back 5

Membranous ossification

Front 6

What is membranous ossification?

Back 6

Woven bone formed directly without cartilage → later remodeled to lamellar bone.

Front 7

What osteoblast do? How they do it?

Back 7

Builds bone by secreting collagen and catalyzing mineralization in alkaline environment via ALP.

Front 8

What osteoclast do? How they do it?

Back 8

Dissolve bone by secreting H+ and collagenases.

Front 9

What PTH do? How it works? From where it's secreted?

Back 9

Parathyroid Hotmone: At low, intermittent levels, exerts anabolic effects (building bone) on osteoblast and osteoclast (indirect).

Front 10

What happens to the bone if there is an ↑ in PTH?

Back 10

↑PTH = catabolic effects (osteitis fibrosa cystica)

--Seen in 1° hyperparathyroidism

Front 11

What role do estrogen has in bone formation?

Back 11

Inhibits apoptosis in bone-forming osteoblast and induces apoptosis in bone-resorbing osteoclast.

Front 12

What happens to the bone in estrogen deficiency? What may cause estrogen deficiency?

Back 12

Excess cycles of remodeling, and bone resorption lead to osteoporosis.

--Surgical removal of ovaries or menopause

Front 13

What mutation is seen in achondroplasia?

Back 13

Fibroblast growth factor receptor 3 (FGFR-3)

Front 14

Is achondroplasia is related with maternal or paternal advance age?

Back 14

Paternal advance age

Front 15

What fails in achondroplasia that manifiest in the affected individual?

Back 15

Failure of longitudinal bone growth (endochondral ossification) → short limbs

Front 16

Which ossification is not affected in achondroplasia?

Back 16

Membranous ossification

Large head relative to limbs.

Front 17

If an heterozygote achondroplastic patient married another heterozygote individual and have children, what percentage might develop achondroplasia?

Back 17

Heterozygote Individual

A= mutation

a= wild type

AA= 25% Homozygote mutation → Death in utero

Aa= 50% Heterozygote mutation → Achondroplasia

aa= Normal individual

Front 18

If an heterozygote achondroplastic patient married a non-achondroplastic individual and have children, what percentage might develop achondroplasia?

Back 18

Heterozygote indivual

A= mutation

a= wild type

Aa= 50% heterozygote mutation → Achondroplasia

aa= 50% normal individual

Front 19

Do achondroplastic patient have normal fertility and life expectancy?

Back 19

Yes, they do.

Delivery must be in a C-section

Front 20

What percentage do mutation in achondroplasia occurs sporadically?

Back 20

Up to 85%.

Front 21

Bone disease 2° to drugs (eg, steroids, alcohol, anticonvulsant, anticoagulants, thyroid replacement therapy)

Back 21

Osteoporosis

Front 22

Bone disease due to ↑ bone resorption related to ↓ estrogen levels

Back 22

Osteoporosis

Front 23

What happens to the bone in osteoporosis?

Back 23

Trabecular (spongy) and cortical bone loss mass and interconnections despite normal bone mineralization and lab values (Ca2+ and PO4-)

Front 24

How is the lab values (Ca2+, PO4-, AP, PTH) in osteoporosis?

Back 24

All normal.

Front 25

What medical conditions are associated with osteoporosis?

Back 25

Hyperparathyroidism

Hyperthyroidism

Multiple Myeloma

Malabsorption syndrome

Front 26

How can osteoporosis be diagnosed?

Back 26

DEXA scan: Dual-Energy X-ray Absorptiometry with a T-Score of ≤ 2.5 or by fragility fracture of hip or vertebra.

Front 27

What measure can be taken to prevent osteoporosis?

Back 27

Exercise (weight-bearing)

Calcium and Vitamin D intake

Avoid Smoking and Alcohol

Watch out/Discontinous glucocorticoids, PPI, H2-blockers

Front 28

How can osteoporosis be treated?

Back 28

Biphosphonates (eg, alendronate)

PTH analog (eg, teriparatide)

SERMS (eg, raloxifene)

RANKL Antibody (eg, denosumab)

Front 29

What is Colles fracture? In what disease it can be seen?

Back 29

Fracture distal radius.

Osteoporosis

Front 30

What fractures can be seen in osteoporosis?

Back 30

Hip fracture / Femoral Neck

Vertebra fracture

Distal radius fracture (Colles)

Front 31

Acute back pain + loss of height + kyphosis

Back 31

Osteoporosis

Front 32

Pancytopenia + thickened, dense bone + Cranial Nerve palsie

Back 32

Osteopetrosis

Front 33

Bone disease with mutation in carbonic anhydrase II

Back 33

Osteopetrosis

Front 34

Bone disease due to failure of normal bone resorption (eg osteoclast failure)

Back 34

Osteopetrosis

Front 35

Bone disease where bone marrow space is filled with bone tissue → Pancytopenia and extramedullary hematopoiesis

Back 35

Osteopetrosis

Front 36

Bone-in-Bone ("stone" bone) appearance on X-ray

Back 36

Osteopetrosis

Front 37

What treat is definitively in osteopetrosis?

Back 37

Bone marrow trasnplant as osteoclast are derive from monocytes

Front 38

From which cell are osteoclast derived?

Back 38

Monocytes

Front 39

How are the lab values (Ca2+, PO4-, PTH, AP) in osteopetrosis?

Back 39

All normal but maybe ans slightly ↑AP

Front 40

Bone disease with defective mineralization of osteoid or cartilagenous growth plates

Back 40

Osteomalacia or Rickets

Front 41

Most common cause of Osteomalacia/Rickets

Back 41

Vitamin D deficiency

Front 42

X-rays shows osteopenia and "Looser zones"

Back 42

Osteomalacia/Rickets

"Looser zones" → pseudofractures

Front 43

Bone disease with bowing of legs, bead-like costochondral junctions and soft skull

Back 43

Rickets

Costocondral junctions → rachitic rosary

Craniotabes → soft skull

Front 44

How are the lab values (Ca2+, PO4-, AP, PTH) in Osteomalacia/Rickets?

Back 44

↓ Vitamin D = ↓Ca2+ → ↑PTH → ↓PO4-

↑AP (hyperactivity of osteoblast - bone turnover)

Front 45

Bone disease where localized disorder of bone remodeling is caused by ↑osteoclastic activity follwed by ↑osteoblastic activity that forms poor-quality bone.

Back 45

Paget disease of bone

Front 46

Long bone chalk-stick fracture on X-ray

Back 46

Paget disease of bone

Front 47

Bone disease with mosaic pattern of woven and lamellar bone (osteocytes with lacunar in chaotic juxtapositions)

Back 47

Paget diseas of bone

Front 48

How are the lab values (Ca2+, PO4-, PTH, AP) seen in Paget disease of bone?

Back 48

Serum Ca2+, PO4-, and PTH are normal.

Only AP is increase!

Front 49

Mention the stages of Paget disease of bone.

Back 49

Lytic = osteoclast

Mixed = osteoclast + osteoblast

Sclerotic = Osteoblast

Quiescent = minimalosteoclast/osteoblast activity

Front 50

With what neoplasia is Paget disease of bone might be associated?

Back 50

Osteosarcoma (osteogenic sarcoma)

Front 51

How does Paget disease of bone can cause heart failure?

Back 51

Sometimes ↑blood flow from ↑arteriovenous shunts may cause high-output heart failure

Front 52

A patient comes complaining that he lost his hearing gradually. He also mention that he can wear his hats anymore because the are getting smaller. What disease you might suspect?

Back 52

Paget disease of bone

Front 53

What artery is comprised in osteonecrosis?

Back 53

Medial circumflex femoral artery

Front 54

What is the common site affected in osteonecrosis?

Back 54

Femoral head.

Front 55

What may cause osteonecrosis?

Back 55

CAST Bent LEGS

Corticosteroids

Alcoholism

Sickle cell

Trauma

"The Bends" (caisson/decompression disease)

LEgg-Calvé-Perthes disease (idiopathic)

Gaucher disease

Slipped capital femoral epiphysis

Front 56

From what artery does medial circumflex femoral artery may be branched?

Back 56

Profunda femoris artery or occasionally from the femoral artery.

Front 57

Back 57

"Soap bubble" appearance.

Giant cell tumor.

Front 58

Back 58

Bony exocitosis with cartilaginous (chondroid) cap.

Osteochondroma.

Front 59

Back 59

Codman triangle (from elevation of periostium)

Osteosarcoma (osteogenic sarcoma)

Front 60

Back 60

Codman traingle (from elevation of periostium)

Osteosarcoma (osteogenic sarcoma)

Front 61

Back 61

Sunburst pattern

Osteosarcoma (osteogenic sarcoma)

Front 62

Back 62

"Onion skinning" appearance

Ewing sarcoma

Front 63

Back 63

Anaplastic small blue cell malignant tumor.

Ewing Sarcoma

Front 64

Back 64

Anaplastic small blue cell malignant tumor.

Ewing sarcoma

Front 65

Ewing sarcoma is associated with what translocation?

Back 65

t11;22 causing fusion protein EWS-FLI 1

Front 66

Bone Tumor Age Association:

A male less than 25 years old → ?

Pt between 20 - 40 years old → ?

A boy less than 15 years old → ?

Bimodal distribution (10-20; >65 years old) → ?

Back 66

Males < 25 y/o → Osteochondroma

Pt 20 - 40 y/o → Giant cell tumor

Boy < 15 y/o → Ewing sarcoma

Bimodal distribution → Osteosarcoma

Front 67

What are the predisposing factor of osteosarcoma?

Back 67

Paget disease of bone

Bone infarcts

Radiation

Familial retinoblastoma

Li-Fraumeni syndrome

Front 68

Most common benign bone tumor

Back 68

Osteochondroma

Front 69

Most common malignant bone tumor in children

Back 69

Osteosarcoma

Front 70

Common localization of bone tumor:

1.Metaphysis of long bone (often aroung the knee)

2. Diaphysis of long bone, pelvis, scapula, ribs

3.Epiphyseal end of long bones (often arounf the knee)

Back 70

1.Osteosarcoma

2.Ewing sarcoma

3.Giant cell tumor

Front 71

What tumor may metastasized to the bone?

Back 71

Prostate, Renal cell cancer, Testes, Thyroid, Lungs, Breast

Front 72

What type of lesion can do metastasic bone tumor? What tumor can cause it? What is the common presentation?

Back 72

Lytic = destroy bone

--Breast, Lung

Blastic = abnormal formation

--Prostate

Presentation: Bone pain, epidural spinal crod compression, hypercalcemia