Pharm - Parathyroid/Calcium

Question 1

What are the 2 types of bone and where are they located?

Answer 1

Cortical = 80% of skeleton, shafts of long bone

Trabecular = vertebral bodies, ribs, pelvis, ends of long bones

Question 2

In bone, what is the major noncellular component that is:

• -Organic?
• -Inorganic?

Answer 2

Organic = Type 1 collagen
Inorganic = Hydroxyapatite

Question 3

Low serum ionized calcium causes [stimulates/suppresses] PTH secretion

Answer 3

Stimulates

Question 4

Where do the 2 modifications of vitamin D occur?

Answer 4

1st hydroxylation = liver

2nd hydroxylation = kidney –> 1,25 (OH)2 Vitamin D

Question 5

What is the normal serum concentration of Calcium?

Answer 5

8.6-10.2 mg/dL

Question 6

What are the 2 most common causes of Hypercalcemia?

Answer 6

Hyperparathyroidism

Malignancy

Question 7

Pertinent lab abnormalities in Primary Hyperparathyroidism

Answer 7

High Ca
High or normal PTH
Low PO4
High Urine Ca

Question 8

2 Most common causes of hyperparathyroidism?

Answer 8

Parathyroid Adenoma – benign, solitary, 80% of cases

Hyperplasia – of all 4 glands

Question 9

Mnemonic for primary hyperparathyroidism symptoms?

Answer 9

Stones = hypercalciuria–> renal stones
Bones = Osteitis fribrosa cystica
Groans = weakness and constipation
Psych overtones = depression

Question 10

Calcimimetics:

• -Mechanism of action?
• -When are they used?

Answer 10

• -Alters Functino of calcium sensing receptor
• -Reduce PTH and serum Ca
• -Used in Primary hyperparathyroidism

Question 11

What does excessive OTC Calcium use cause?

Answer 11

Milk Alkali Syndrome

Question 12

Autosomal Dominant trait
Normal to slightly high PTH
Low urine calcium
Mechanism: defective Ca sensing receptor --> need more Ca to suppress PTH --> excessive renal Ca reuptake
What disease?

Answer 12

Familial Hypocalciuric hypercalcemia = mild hypercalcemia, hypocalciuria, normal to high PTH

Question 13

What diuretic class can cause

• -hypercalcemia?
• -hypocalcemia?

Answer 13

Hypercalcemia = Thiazides – increase Ca reabsorption in distal tubule

Hypocalcemia = Loop – decrease positive lumen voltate –> less Ca and Mg reabsorption at TAL

Question 14

Granulomatous Diseases can cause [Hyper/Hypo] calcemia

Answer 14

HypERcalcemia – increaseD 1,25(OH)2D

Question 15

Important points about calcitonin use in hypercalcemia:

Answer 15

• -Increases urinary Ca secretion, inhibit bone resorption
• -Rapid effect = good for acute setting
• -Tachyphylaxis in 2-3 days = tolerance

Question 16

Pertinent lab abnormalities in secondary hyperparathyroidism

Answer 16

Low Ca = decreased absorption (main cause)
High PO4 = Renal failure –> can’t excrete PO4
or Low PO4 = in other causes
Low 1,25(OH)2D = lack of 1-a-hydoxylase activity –> decreased Ca absorption

Question 17

Pertinent lab abnormalities in tertiary hyperparathyroidism

Answer 17

Parathyroid gland becoming autonomous(Refractory) after prolonged 2ndary hyperparthyroidism (renal disease):
High Ca
Very High PTH

Question 18

What is the most common cause of hypocalcemia?

Answer 18

Chronic Renal Failure
High PO4
High PTH
High Cr

Question 19

What are the D3 and D2 forms of vitamin D called?

Answer 19

D2 = Ergocalciferol 
D3 = Cholecalciferol --more efficacious

Question 20

Bone mineral density in normal, osteopenia, and osteoporosis

Answer 20

Normal = greater than -1
Osteopenia = -1 to -2.5
Osteoporosis = less than -2.5

Question 21

What drug class is approved for osteoporosis only in postmenopausal women?

Answer 21

Selective Estrogen Receptor Modulators – Raloxifene, Tamoxifen, Basedoxifene, Lasofoxifene

• -protective against breast cancer
• -risk of DVT

Question 22

What hormone inhibits osteoclast resorption of bone and where is it produced?

Answer 22

Calcitonin – C-cells of the thyroid

Question 23

What osteoporosis drug is a PTH analog?

Side effects?

Answer 23

Teriparatide – anabolic agent
Side effects: dizziness, palpitations, transient hypercalcemia

*Black box warning = osteosarcoma in rats

Question 24

Denosumab mechanism of action:

Answer 24

RANK Ligand inhibitor –> antiresoprtive for osteoporosis

Question 25

Aledronate, Ibandronate, Risedronate, and Zoledronate are of this drug class

Answer 25

Bisphosphonates – pyrophosphate analogs, bind hydroxyapatite, inhibit osteoclast activity

Question 26

[FA]

How does pH affect Calcium?

Answer 26

high pH –> high affinity of albumin ((-) charge) to Ca –> hypocalcemia –> cramps, pain, paresthesias, carpopedal spasm

Question 27

[FA]

When is PTH-related peptide abnormal?

Answer 27

Increased in malignancies (eg. SCC of lung, RCC)

Question 28

[FA]

How does low and very low Mg levels affect PTH?

Answer 28

Low serum Mg –> increased PTH secretion (b/c feedback inhibition)

Very low serum Mg –> decreased PTH secretion (no feedback = ion independent suppression)