Pathophys of metabolic bone disorders

Question 1

Define metabolic bone disease

Answer 1

imbalance of bone remodeling

Question 2

How can bone remodeling be measured?

Answer 2

biochemical markers of bone resorption and formation

Question 3

What is cathepsin K?

Answer 3

highly expressed in osteoclast, where it is localized in the lysosome and released in bone resoprtion

Question 4

Wnt pathway activation _____ new bone formation. What inhibits Wnt signaling?

Answer 4

increases. Inhibited by sclerostin

Question 5

Sclerostin _____ regulates bone formation

Answer 5

negatively

Question 6

Bone loss can result in ____, a condition of bone fragility, that is a silent disease until it ends up in fracture.

Answer 6

osteoporosis

Question 7

Define osteoporosis.

Answer 7

a skeletal disorder characterized by compromised bone strength and an increased risk of fracture.

Question 8

Bone strength reflects the integration of what two main features?

Answer 8

bone density and bone quality

Question 9

Important risk factors for fracture

Answer 9

Age: major contributor
Gender: woman>men
BMD
BMI

Question 10

What are lifestyle risk factors for osteoporosis?

Answer 10

alcohol abuse, smoking, immobilization, excessive thinness, high salt intake

Question 11

What are nutritional risk factors with osteoporosis?

Answer 11

low calcium intake, low vitamin D intake, excess vitamin A intake.

Question 12

What hormonal abnormalities with osteoporosis?

Answer 12

hyperparathyroidism, low testosterone or androgen insensitivity, low estrogen (menopause), excess cortisol, thyrotoxicoses, T1D, T2D, adrenal insufficiency

Question 13

What GI disorders are associated with osteoporosis?

Answer 13

celiac disease, gastric bypass, IBD, GI surgery, malabsorption, pancreatic disease, primary biliary cirrhosis.

Question 14

What genetic factors are associated with osteoporosis?

Answer 14

CF, ehler-danlos, Gaucher’s, glycogen storage, hemochromatosis, homocystinuria, hypophosphatasis, idiopathic hypercalciuria, marfan, menkes steely hair syndrome, OI, porphyria, riley-day syndrome

Question 15

What heme disorders are associated with osteoporosis?

Answer 15

MM, hemophilia, thalassemia, monoclonal gammopathies, leukemia and lymphoma, SCD, systemic mastocytosis

Question 16

What rheum and autoimmune disorders are associated with OP?

Answer 16

ankylosing spondylitis, lupus, RA

Question 17

What CNS disorders are associated with OP?

Answer 17

epilepsy, MS, parkinsons, spinal cord injury, stroke

Question 18

In a nut shell, what is associated with OP?

Answer 18

everything. including AIDS. and every drug.

Question 19

What blood tests should be done if you suspect osteoporosis?

Answer 19

PTH, VD, CMP, PO4, Mg, TSH, testosterone, CBC, 24 hour urine calcium

Question 20

What is the DEXA bone scan Z score?

Answer 20

bone density compared to age, sex, ethinicity matched reference population

Question 21

What is the DEXA T score?

Answer 21

bone density compared to a young adult reference population

Question 22

WHO diagnostic classification does not apply to:

Answer 22

premenopausal women, men less than 50 y/o, children

Question 23

Indications for bone density testing

Answer 23

women 65 and older, men 70 and older regardless of risk factors
Younger postmen. women or men 50-69 with fracture risk factors.
Any adult with fracture after age 50
Adults with a condition or taking meds associated with low bone mass.

Question 24

What is the role of vertebral fractures in OP diagnosis?

Answer 24

Any low trauma even painless fracture is consistent with a diagnosis of OP even in the absence of bone density diagnosis. Most are asymptomatic when they occur.

Question 25

Biochemical markers of bone formation

Answer 25

bone specific alkaline phosphatase, osteocalcin, aminoterminal propeptide of type 1 procollagen

Question 26

markers of bone resoprtion

Answer 26

Serum C-telopeptide

urinary N-telopeptide

Question 27

What is FRAX

Answer 27

calculation of the 10 year probability of hip fracture and then 10 years prob. of a major OP fracture. Intended for postmen women and men older than 50.