Deck 33: Bone Disease

Question 1

Elevations of this analyte are seen in bone diseases characterized by increased osteoblastic activity, including Paget's disease, osteomalacia, osteitis fibrosa, and renal osteodystrophy.Decreased serum concentrations of PTH, thyroid hormone, or growth hormone are associated with a decrease in the serum concentration of this analyte.

A)hydroxyproline
B)alkaline phosphatase
C)osteocalcin
D)nephrogenous cyclic AMP

Answer 1

osteocalcin

Question 2

Which of the following is not a risk factor associated with low bone density and fracture?

A)high weight and body mass index
B)low endogenous estrogen
C)hypogonadism
D)smoking and alcohol use

Answer 2

high weight and body mass index

Question 3

Calcitonin (CT):
1)is generally regarded as one of three hormones responsible for the control of calcium and phosphorus homeostasis.
2)causes a prompt increase in serum calcium and phosphorus concentrations following intravenous administration.
3)is produced by the parafollicular C cells of the thyroid gland.
4)is rapidly excreted, with a half-life of 10 minutes after intravenous administration.

A)1, 2, 3, 4
B)1, 2, 3
C)1, 2, 4
D)1, 3, 4

Answer 3

1, 3, 4

Question 4

Which of the following is not a biochemical marker of bone formation?

A)serum osteocalcin
B)serum alkaline phosphatase (ALP)
C)serum tartrate-resistant acid phosphatase
D)serum procollagen I extension peptides

Question 5

Estrogen increases bone mass and bone mineral density by:
1)reducing bone resorption by directly preventing osteoclast differentiation, activity, and survival and indirectly by stimulating the secretion of calcitonin.
2)increasing collagen synthesis and osteoid formation.
3)enhancing the absorption of calcium across the intestines.

A)1, 2, 3
B)1, 2
C)2, 3
D)1, 3

Question 6

Zollinger-Ellison syndrome will show which of the following laboratory observations?

A)They all show an abnormal serum calcitonin concentration deficiency.
B)They all show an abnormal serum calcitonin concentration excess.
C)They all show an abnormal serum alkaline phosphatase deficiency.
D)They all show an abnormal serum alkaline phosphatase excess.

Question 7

All of the following statements are true of osteoblasts except:

A)They are found along surfaces of both cortical and trabecular bone.
B)They have receptors for a large number of hormones.
C)As they become embedded in bone matrix, they differentiate into mature osteocytes.
D)They synthesize small amounts of matrix continuously to maintain bone integrity, and they are able to resorb bone in exceptional circumstances when normal mineral homeostasis is altered.

Question 8

Primary hyperparathyroidism:
1)causes an increased serum phosphorus.
2)causes an increased serum calcium.
3)is usually discovered in adulthood.
4)is predominantly seen in postmenopausal women.

A)1, 2, 3, 4
B)1, 2, 3
C)1, 3, 4
D)2, 3, 4

Question 9

Given the following laboratory information, what is the most probable metabolic bone disease?
Calcium - decreased
Phosphorus - decreased
PTH - increased
Alkaline phosphatase - increased
Calcidiol - decreased or normal
Calcitriol - decreased or normal

A)osteoporosis
B)osteomalacia
C)osteitis fibrosa
D)none of the above

Question 10

Which of the following diseases and conditions are associated with calcidiol (25-hydroxy-cholecalciferol) excess?
1)vitamin D intoxication
2)nephrotic syndrome
3)excessive sunlight exposure
4)sarcoidosis

A)1, 3, 4
B)1, 3
C)2, 4
D)2, 3, 4

Question 11

Long bone:
1)are confined to the limbs.
2)consist of a diaphysis, epiphyses, and metaphysis.
3)consist of cortical bone that encloses a layer of trabecular bone.

A)1, 2, 3
B)1, 2
C)2, 3
D)1, 3

Question 12

Which of the following tests can be used to rule out secondary osteoporosis?
1)serum alkaline phosphatase
2)serum total protein
3)serum calcium
4)serum testosterone

A)1, 2, 3, 4
B)1, 2, 3
C)1, 3, 4
D)2, 3, 4

Question 13

Parathyroid hormone (PTH) acts on the bone and kidney to produce three major effects: ______ in serum calcium concentrations, ______ in serum phosphorus concentrations, and ______ in the active hormonal form of vitamin D (calcitriol).

A)increase, decrease, increase
B)increase, increase, decrease
C)decrease, increase, decrease
D)decrease, decrease, increase

Question 14

Hypercalcemia can be seen in:

A)Addison's disease
B)withdrawal of steroids
C)primary hyperparathyroidism
D)all of the above

Question 15

Select the proper order for the following stages of Paget's Disease.
1)Bone formation predominates; the pagetic bone is coarse-fibered, dense, trabecular bone.
2)Resorption predominates, and the bone marrow is replaced with a highly vascular fibrous connective tissue.
3)The rate of bone resorption declines, and continued bone formation produces hard, dense bone.

A)1, 2, 3
B)2, 1, 3
C)1, 3, 2
D)2, 3, 1

Question 16

Which of the following qualify as criteria for a female patient to have a bone-density scan?

A)over 65 years old
B)postmenopausal with at least one risk factor besides menopause, or with a fracture
C)on prolonged hormone-replacement therapy
D)all of the above

Question 17

In the blood stream, calcium exists in three forms: ______ of total serum calcium is the biologically active ionized calcium, ______ is protein bound, mainly to albumin, and ______ is complexed to anions.

A)10%, 45%, 45%
B)45%, 45%, 10%
C)35%, 10%, 55%
D)10%, 55%, 35%