Bone Physiology And Metabolic Bone Disease

Front 1

Free Calcium is regulated by what two chemicals mainly and by a third insignificantly?

Back 1

1. PTH 2. Calcitriol 3. Calcitonin

Front 2

Acidosis causes free calcium to???

Back 2

Free calcium increases in acidotic environments and decreases in alkaline environments because it competes with H+ for binding sites.

Front 3

80% of bound Calcium is bound to ______ and 20% is bound to ______.

Back 3

1. Albumin (30 binding sites for Ca) 2. Globulins

Front 4

Free, bound, or total Calcium is the best indicator of calcium status during lab testing??

Back 4

Free calcium

Front 5

PTH is regulated by what chemical?

Back 5

Calcium

Front 6

PTH stimulates _____ to increase bone ________ with the help of ________.

Back 6

1. osteoclasts 2. resorption 3. calcitriol

Front 7

PTH _________ reabsorption of calcium in _______ and _______.

Back 7

1. increases 2. distal tubule 3. loop of Henle

Front 8

PTH inhibits proximal renal tubular reabsorption of ________ and _________.

Back 8

Phosphate and HCO3-

Front 9

_________ stimulates renal hydroxylation of 25 (OH)D to 1,25 (OH)2D.

Back 9

PTH

Front 10

Excess PTH can lead to a condition called _______.

Back 10

Mild hyperchloremic metabolic acidosis.

Front 11

Parathyroid Hormone-Related Protein is produced by _______ and is homologous to PTH.

Back 11

solid tumors.

Front 12

PTH-RP is elevated in the serum of 50-90% of patients with _________ but not _________.

Back 12

1. malignancy-associated hypercalcemia 2. hyperparathyroidism.

Front 13

At pharmacological levels, calcitonin inhibits _______ and lowers ______ and ______.

Back 13

osteoclastic bone resorption...serum calcium...serum phosphate

Front 14

At pharmacological levels, calcitonin _______ tubular absorption of calcium and phosphate in the kidneys.

Back 14

decreases

Front 15

With medullary thyroid carcinoma, ______ is elevated and is an important tumor marker. This leads to ______ in serum calcium levels.

Back 15

1. calcitonin 2. no change

Front 16

Calcitriol activation is stimulated by _____ and _____.

Back 16

PTH ....low serum phosphorus

Front 17

Calcitriol activation is inhibited by ______ and ______

Back 17

1,25 (OH)2D.....elevated serum phosphorus

Front 18

What's the function of calcitriol in the small intestine?

Back 18

Increase absorption of phosphorus and calcium.

Front 19

What's the function of calcitriol in bone?

Back 19

Stimulates Ca & P resorption from bone along with PTH and, at high levels, can induce monocytic stem cells in bone marrow to differentiate into osteoclasts.

Front 20

What's the role of calcitriol in the kidneys?

Back 20

Increase Ca resorption by the distal tubule.

Front 21

Other roles of calcitriol?

Back 21

1. regulates PTH secretion. 2. possible role in cell metabolism and differentiation.

Front 22

If no liver or pregnancy, increased Alkaline Phosphatase is due to increased ______.

Back 22

Bone formation.

Front 23

This biomarker is produced solely by osteoblasts and released into serum during periods of bone formation. It avidly binds Ca.

Back 23

Osteocalcin.

Front 24

These are markers for increased type 1 collagen synthesis and increase in serum during increase in collagen synthesis.

Back 24

Propeptides of Type 1 Procollagen

Front 25

These two biomarkers present in urine, when increased, denote increased bone resorption. Nonspecific tests.

Back 25

Urine calcium and urine hydroxyproline.

Front 26

High concentration of ______ and ______ crosslinks denotes ______ bone resorption. Very specific test for urine or serum.

Back 26

telopeptides.....pyridinium....increased

Front 27

Which compound when cross-linked, pyridinium or deoxypyridinium, is more common in bone collagen and therefore more specific for bone resorption?

Back 27

Deoxypyridinium

Front 28

Which telopeptide is more specific for type 1 bone collagen? N-terminal or C-terminal?

Back 28

N-terminal

Front 29

Most common cause of hypercalcemia in outpatient setting???

Back 29

Primary hyperparathyroidism--> due to adenomas, hyperplasia, carcinomas, MEN syndromes, etc.

Front 30

Most common cause of hypercalcemia in hospital setting?

Back 30

Malignancy and bone involvement--> bone cancers or mets ie multiple myeloma, metastatic breast carcinoma. No bone involvement usually denotes humoral hypercalcemia of malignancy that produces PTH-RP

Front 31

Medications that produce hypercalcemia?

Back 31

antacids, thiazide diuretics, lithium therapy, vitamin A

Front 32

Vitamin D intoxication will show high serum ____ and _____, low serum _____ and down-regulation of the enzyme ______.

Back 32

Ca....Phosphate.....PTH....1 alpha hydroxylase

Front 33

Causes of hypocalcemia?

Back 33

1. decreased PTH or hypoparathyroidism 2. Mg deficiency 3. resistance to PTH or pseudohypoparathyroidism 4. chronic renal failure 5. vitamin D disorders 6. acute pancreatitis

Front 34

Chronic renal failure can lead to decreased _____ excretion, decreased _____ absorption, and a condition known as secondary ______.

Back 34

phosphate......calcium......secondary hyperparathyroidism

Front 35

80% of hypocalcemia are due to ....

Back 35

Pseudohypocalcemia or artifactual (protein-bound) hypocalcemia due to hypoalbuminemia.

Front 36

Osteomalacia is a disease characterized by defective ______ during bone _____ and moderate to severe deficiency of _______.

Back 36

mineralization.....formation.....calcidiol and calcitriol

Front 37

Osteomalacia causes a compensatory rise in _____ leading to a condition called ______ which then causes a reduction in _____.

Back 37

PTH...secondary hyperparathyroidism....phosphate.

Front 38

In Paget's disease, pt's are usually asymptomatic but high levels of _____ can be diagnostic. Remainder of biochemical findings are often normal.

Back 38

serum alkaline phosphatase (up to tenfold). Late stage Paget's disease will also show markers of bone resorption such as pyridinium cross-links.

Front 39

In high-turnover renal osteodystrophy, one will see elevated serum levels of ______ ,______ & ______ reduced serum levels of ______ and _____, and induces a condition called ______.

Back 39

phosphate, alkaline phosphatase, PTH....calcitriol.....calcium....secondary hyperparathyroidism.

Front 40

In osteoporosis, traditional biochemical markers are normal so how is it diagnosed?

Back 40

Markers of bone remodeling are assessed but not diagnostic and secondary causes of osteoporosis are excluded.