Metabolic Bone Disease

Question 1

What is Osteoprotegerin?

Answer 1

It is a decoy receptor that binds to RANK-L and

prevents it from attaching to RANK; it is therefore a major endogenous inhibitor of bone remodeling

Question 2

What are Fragility fractures

Answer 2

Bone fractures that occur with low trauma (a fall from a standing height or less)

Question 3

The most common fragility fractures are ______

Answer 3

vertebral fractures, hip fractures and wrist fractures

Question 4

Using bone densitometry criteria,
osteoporosis is diagnosed when the lowest T-score is _____ and osteopenia is diagnosed when the lowest T-score is ______, whereas BMD is normal when T-scores at all sites are ______

Answer 4

< -2.5,
-1.0 to -2.4,
> -1.0.

Question 5

Using the FRAX tool to calculate 10 year probability of a fragility fracture, treatment is generally
recommended if the fracture risk is ______ for hip fracture or _____for a major osteoporosis fracture.

Answer 5

> 3%,

> 20%

Question 6

calcium carbonate absorption is significantly reduced in patients who have ______

Answer 6

deficient gastric acid production (atrophic gastritis and proton pump inhibitors).

Question 7

How is new bone formed?

Answer 7

Osteoblasts migrate into pits (made by osteoclasts) and secrete osteoid (bone specific collagen) which subsequently become mineralized with calcium-phosphate (hydroxyapatite) crystals to form strong new bone

Question 8

_______is defined as impaired bone mineralization resulting in soft, weak bones. It is caused by any
condition that results in a low extracellular fluid calcium x phosphate product that is insufficient to mineralize
bone osteoid.

Answer 8

Osteomalacia

Question 9

What is Paget’s disease of bone?

Answer 9

idiopathic condition of bone characterized by excessive and unregulated bone resorption and formation.

Question 10

The _____ gene has been found in 40-80% of families with Paget’s disease

Answer 10

Sequestosome I/P62

Question 11

The most commonly affected bones in paget’s disease are the ___

Answer 11

pelvis, skull, vertebrae, tibia and fibula

Question 12

What are the biomarkers of osteoclastic bone resorption

Answer 12

Ntelopeptides, C-telopeptides, Pyridinoline crosslinks

Question 13

What are the biomarkers of bone formation

Answer 13

alkaline phosphatase, osteocalcin

Question 14

Treatment options for pagets disease include _____

Answer 14

oral and intravenous bisphosphonates,

calcitonin, analgesics, non-steroidal anti-inflammatory drugs, and corrective surgery for deformities.

Question 15

______ is the treatment for congenital 1 alpha hydroxylase deficiency (vitamin D dependent rickets type 1), and in very high doses for congenital vitamin D receptor deficiency (vitamin D dependent rickets type 2).

Answer 15

Calcitriol