metabolic bone dz

Question 1

RANK

Answer 1

receptor on osteoclasts which facilitates bone resorption when RANK-L binds to it.

Question 2

OPG

Answer 2

osteoprotegerin- a decoy RANK-L receptor which decreases bone resorption

Question 3

Risk factors for fragility fractures of osteoporosis

Answer 3

Previous Fractures, Age (increases after 55), Falls, Low Bone Mass

Question 4

How do vertebral fractures affect fracture risk

Answer 4

Increases risk by 5% of having another fracture

Question 5

compare osteoporosis vs osteopenia

Answer 5

Osteopenia: Bone mineral density T score of -1 to -2.5 Osteoporosis: bone mideral density T score of < -2.5. Normal: BMD T score of >-1.0

Question 6

normal bone remodeling

Answer 6

Resorption= formation, OC= OB, old bone = new bone. Bone mass remains stable

Question 7

Non-modifiable risk factors for low bone mass

Answer 7

Age, Race, Gender, Family History, Early Menopause

Question 8

Modifiable risk factors for low bone mass

Answer 8

Low Calcium Intake, Low Vitamin D Intake, Estrogen Deficiency, Sedentary Lifestyle, Cigarette Smoking, Excess Alcohol (> 2/day), Excess Caffeine (> 2/day), Medications

Question 9

How is diagnosis of osteoporosis/osteopenia made

Answer 9

measure bone density at and base T score on lowest density site

Question 10

Who is treated for osteoporosis

Answer 10

Anyone with a fragility fracture, vertebral fracture, hip fracture or T score 3% risk of hip fracture of >20% major OP fracture

Question 11

Osteoporosis prevention and treatment

Answer 11

1. Ca- 1000-1500mg/day. Supplement if dairy intake insufficient. 2. Vitamin D. 3. exercise- aerobic and resistance. 4. falls- assess and prevent

Question 12

osteoporosis treatment

Answer 12

1. anti-resorptive agents: bisphosphanates, denosumab, raloxifene, calcitonin, estrogens. 2. anabolic agents: teriparatide, romosozumab

Question 13

Define osteomalacia

Answer 13

impaired bone mineralization due to inadequate Ca and Phosphate resulting in soft, weak bones. Called rickets in kids

Question 14

Causes of osteomalacia and rickets

Answer 14

1. Vitamin D deficiencies- poor intake/sunlight, renal dz, hypoparathyroidism, congenital. 2. phosphate disorders- poor intak, renal phosphate wasting, congenital (Vitamin D resistant rickets- impaired Vit D formation or renal phosphate wasting)

Question 15

clinical features of osteomalacia and rickets

Answer 15

osteomalacia: pain, deformities, fractures. Rickets: pain, deformities, muscle weakness, short stature

Question 16

Osteomalacia/rickets labs

Answer 16

Decreased Ca, decreased phosphate, increased serum alkaline phosphatase, increased serum PTH, decreased urine Ca

Question 17

osteomalacia radiology

Answer 17

fractures, pseudofractures- milkmans fractures, loosers lines

Question 18

rickets radiology

Answer 18

Bowing of long bones, flaring ends of long bones, delayed epiphyseal calcification

Question 19

osteomalacia/rickets treatment

Answer 19

1. Nutritional Vitamin D Deficiency- Vitamin D and Calcium. 2. Congenital 1 Alpha Hydroxylase Deficiency- Calcitriol and Calcium. 3. Congenital Vitamin D Receptor Deficiency- High Dose Vitamin D or Calcitriol and Calcium. 4. Congenital Hypophosphatemic Rickets- Calcitriol and Phosphate

Question 20

Define pagets

Answer 20

An Idiopathic Bone Condition Characterized by Excessive/Unregulated Bone Resorption and Formation

Question 21

Etiology of pagets disease

Answer 21

genetic component (enhances osteoclast formation/reactivity) plus chronic paramyxovirus infection (induces changes in osteoclast precursors)

Question 22

Gene linked to Pagets disease

Answer 22

Sequestosome I/ p26- a ubiquitin binding protein that induces NF-kB activation and osteoclast differentiation/activity/survival.

Question 23

Clues to the viral cause of pagets disease

Answer 23

it is associated with dog owners, specific locations (rare in africa/asia), osteoclasts show paramyxovirus-like inclusions in nuclei + cytoplasm.

Question 24

Pagets disease skeletal features

Answer 24

pain, deformity, fractures, osteoarthritis, hypervascularity, acetabular protrusion, osteogenic sarcoma. Commonly involves pelvis, skull, vertebrae, femur and tibia

Question 25

Pagets disease neurological clinical features

Answer 25

deafness (8th nerve, ossicles), cranial nerve compression (bony), spinal cord compression (vascular)

Question 26

Pagets disease cardiovascular features

Answer 26

Atherosclerosis, Aortic Stenosis, Congestive Heart Failure
(High Output)Atherosclerosis, Aortic Stenosis, Congestive Heart Failure
(High Output)

Question 27

pagets dz over time

Answer 27

high osteoclast activity > osteoclast and osteoblast activity equal > osteoblast activity higher

Question 28

Pagets dz labs over time

Answer 28

elevated NTX/CTX (bone resorption marker) > elevated NTX/ CTX and elevated alkaline phosphatase (bone formation marker) > decreased NTX/ CTX and elevated or decreased alk phosph

Question 29

Pagets disease diagnosis

Answer 29

1. elevated remodeling markers (NTX/ CTX, alk phos). 2. X ray features (very specific). 3. bone scan (very sensitive). 4. bone biopsy (occassionally needed)

Question 30

Pagets radiology

Answer 30

1. Osteolytic Lesions- “Blade of Grass” Sign in Long Bones, Resorption Front in Flat Bones (~1 cm/yr). 2. Osteosclerotic Lesions near Lytic Areas. 3. Thickened, Disorganized Trabeculae. 4. Thickened, Expanded Cortex. 5. Expansion of Bone Size

Question 31

Pagets bone scan

Answer 31

Focal areas of intense uptake

Question 32

Pagets histology

Answer 32

Increased Osteoclast Numbers, Increased Osteoclast Nuclei (20-100 per cell),Increased Osteoblasts in Periphery, Disorganized Mosaic Woven Bone

Question 33

When to treat Pagets disease

Answer 33

Pagetic Pain, Deformity or Fracture, Weight Bearing Bone Involvement, Extensive Skull Involvement, Neurological Complication, Impending Surgery on Pagetic Bone, Immobilization Hypercalcemia, Alkaline Phosphatase > 2 x Normal

Question 34

Pagets disease treatment

Answer 34

1. anti-resorptive agents- bisphosphonates, calcitonin. 2. analgesics/NSAIDs. 3. corrective surgery