Bone Mineralization-----------------------------------EXAM2 Flashcards

1
Q

What is balance?

A

Long term adjustments to maintain total Ca2+ [ ]

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2
Q

What are osteoclasts responsible for?

A

Removal of bone matrix

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3
Q

What are osteoblasts responsible for?

A

Produce bone matrix , control mineralization

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4
Q
  1. What are the two major mineral constituents?
A

Calcium

phosphate

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5
Q

T/F: Small amounts of Ca exist in the free/active form?

A

True

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6
Q
  1. What percent of phosphate exists in crystalline form?
A

85%

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7
Q

Name the two 1o regulators for calcium/phosphate?

A

Parathyroid Hormone

Vitamin D

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8
Q
  1. What are the 2o regulators for calcium/phosphate?
A

Calcitonin, Glucocorticoids, Estrogen

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9
Q

Parathyroid H

  1. Main Goals? *****
A

Inc calcium

Dec phosphate

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10
Q

Effects on the Kidneys?

A

􏰀 Increase Calcium, Magnesium reabsorption

􏰀 Decrease Phosphate reabsorption at distal tubule

􏰀 Stimulate the production of Calcitriol (1,25 [OH]2D)

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11
Q

PTH

Effects on Intestines?

A

No Direct Effect

Indirectly promotes absorption of Calcium through
stimulation of Vitamin D

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12
Q

Vitamin D

T/F. When pts aren’t exposed to UV light you may supplement with Vitamin D

A

T

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13
Q

Vitamin D

Activation of Vitamin D is?

A

Endogenous Production

Sun-Liver-Kidney

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14
Q
  1. What is the active form of Vitamin D
A

Clcitriol

Doesnt need hydrox in kidney to be active

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15
Q

Main Goals of Vitamin D?

A

􏰀 Increase Calcium

􏰀 Increase Phosphate

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16
Q
  1. Sites of Action

Vitamin D

A

Intestine, Bone, and Kidneys

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17
Q

What is Paget’s Disease?

A

􏰀 Local areas of bone become Hyperactive
􏰀 Replace normal matrix w/ softened & enlarged bone
􏰀 Seen mainly in males and bowed legs

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18
Q

What is the normal total serum concentration of Ca2+?

The normal ionized serum Ca2+ concentrations?

** calcium must be adjusted for hypoalbuminemia

A

􏰀 8.5 – 10.5 mg/dL
􏰀 4.6 – 5.1 mg/dL

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19
Q
  1. T/F. Calcium must be adjusted for hypo-albuminemia.
A

T

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20
Q

. What are the effects of alkalosis?

A

􏰀 Decreased calcium concentrations (because calcium protein binding increased)

􏰀 Calcium protein binding increased

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21
Q

What are the effects of acidosis?

A

􏰀 Increased calcium concentrations
􏰀 Calcium protein binding decreased

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22
Q

Hypocalcemia

  1. What is the hallmark sign of hypocalcemia? ****
A

Tetany

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23
Q
  1. T/F. Hypocalcemia associated with hypo-albuminemia does not need treatment?
A

T

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24
Q

What is the goal of therapy in acute hypocalcemia?

A

Administer 200 – 300mg

of Ca2+ by IV

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25
Q

What Ca2+ agent is preferred to correct hypocalcemia?

A

Calcium gluconate (2-3 grams)

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26
Q

What are some ADRs with rapid administration (IV) of calcium?

A

Hypotension
􏰀 Bradycardia
􏰀 Cardiac asystole

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27
Q
  1. What is the T(x) if patient has chronic hypocalcemia?
A

􏰀 Calcium supplementation w/ oral calcium salts
􏰀 Vitamin D supplementation

28
Q

What type of bone is lost in osteoporosis?

A

Trabecular and cortical bone

29
Q

What is the epidemiology of osteoporosis?

* women & Caucasian/Asians mostly

A

􏰀 Women
lose 35% of cortical bone over lifetime 􏰁bone mass declines 3% per decade and 9% after menopause

􏰀 Men
lose 23% over lifetime

30
Q

Who is at risk for corticosteroid induced osteoporosis?

A

Asthmatics, **
CT disorders
􏰀 Rheumatoid arthritis, **
transplant patients

31
Q
  1. What is the optimal Ca2+ intake for men?
A

􏰀 25-65 years􏰁1000mg
􏰀 >65 years􏰁1500mg

32
Q
  1. What is the optimal Ca2+ intake for women? *****
A

􏰀 25-50 years􏰁1000mg
􏰀 Pregnant/nursing 􏰁 1200mg
􏰀 Post menopause􏰁1000 or 1500mg (+/- estrogen)
􏰀 >65 years􏰁1500mg

33
Q

What are some dietary sources of Calcium?

A

􏰀 Dairy products
􏰀 Shellfish
􏰀 Vegetables (green/leafy) & tofu

34
Q

What type of supplementation should you take if you have osteoporosis?

A

􏰀 Vitamin D at 400 – 800 IU per day
􏰀 Calcium (elemental)
* carbonate􏰁40% * citrate􏰁21%
* lactate􏰁13%
* gluconate􏰁9%

35
Q

What agents are most common for T(x)?

A

Bisphosphonates (inhibit bone reabsorption)

36
Q

Which bisphos ↑ bone mass 2-3%

A

Etidronate (1st generation)

37
Q
  1. Which bisphos is not approved for osteoporosis?
A

Pamidronate (2nd generation)

38
Q

What does alendronate (2nd generation) do?

A

􏰀 Normal bone forms w/ drug use at 3 months
􏰀 Do not allow pt to lie down w/in 45min of taking dose

39
Q

Name another bisphos 2nd generation drug?

A

􏰀 Risedronate
􏰀 Don’t let pt lie down w/in 45min of taking dose because
can cause erosive esophagitis

40
Q
  1. Name a newer bisphos for osteoporosis T(x)?
A

􏰀 Ibandronate (Boniva)
􏰀 Can take daily, once a month, or injection every 3 mths

41
Q

How is calcitonin taken for osteoporosis?

A

IM/SQ injection
􏰀 Nasal spray

42
Q

What are some ADRs of calcitonin for osteoporosis?

A

􏰀 Resistance due to formation of Abs after 2-18mths
􏰀 Local irritation at injection site
􏰀 Rhinitis, irritation, erythema from nasal spray

43
Q

What is homeostasis?

A

Immediate adjustments to maintain free Ca2+ [ ]

44
Q

PTH

A

Inc Ca, dec P

45
Q

Treatment for hypercalcium

Loop Bi CoCa w Hydration

A

Loop diuretic

46
Q

Bone mineral homeostasis

Homeostasis- immediate

A

Balance- long term

47
Q

Hypercalcemia

What should you do if total Ca2+ is

A

Initiate therapy only if patient is symptomatic

48
Q

What should you do if total Ca2+ is >13.5 – 14 mg/dL?

A

Initiate therapy regardless of symptomatology

49
Q

What are basic signs/symptoms of hypercalcemia?

A

Neurological, GI, Renal, and CV effects

􏰀 Extra-skeletal calcification

50
Q

What is the normal pharm T(x) for hypercalcemia?

A

􏰀 Hydration with normal saline
􏰀 Acute management give 2-6 liters w/in 24hrs
􏰀 See 1.6-2.4 mg/dL ↓ in Ca2+ concentrations

51
Q

What do loop diuretics do in hypercalcemia?

Furosemide
Bumetanide
Toresemide

A

􏰀 Inhibit Ca2+ reabsorption in ascending loop of Henle

52
Q

What do bisphosphates do in hypercalcemia?

A

􏰀 Inhibit attachment of osteoclasts to the mineralized matrix
􏰀 Ca2+ concentrations decline in about 3 days
􏰀 Nadir (lowest Ca2+ concentration) is reached in 7 days
􏰀 Wait at least 7 days before you give another dose
􏰀 Pemidronate is most common bisphos for T(x)

53
Q

What is calcitonin?

A

􏰀 A secondary regulator of bone homeostasis

􏰀 Hormone made by the C- cells of thyroid

54
Q

Main goals of calcitonin?

A

􏰀 Decrease calcium
􏰀 Decrease phosphate

55
Q

Where are the calcitonin sites of action?

A

Bone (primary) and kidney

56
Q

What are corticosteroids?

A

􏰀 Secondary regulators of bone homeostasis
􏰀 Made by the adrenal cortex
􏰀 Decrease Ca2+ levels w/in 7 days
􏰀 T(x) limited to granulomatous/lymphoproliferative dz

57
Q
  1. Where are the corticosteroid sites of action?
A

􏰀 Intestine and bone
􏰀 Kidneys

􏰁increase renal excretion of Ca2+

58
Q

What is the normal serum phosphate concentration?

A

3 -4.5 mg/dL

59
Q

T/F. Signs/symptoms of hyperphosphatemia are the same as hypocalcemia?

A

T

60
Q

What are the important pharmacological phosphate binding agents used to treat hyperphosphatemia?

A

Aluminum, calcium, and magnesium containing salts which help to bind phosphate

61
Q

What is an ADR when using calcium salts for hyper?

A

Increased Ca2+ concentrations may predispose patients to metastatic calcification

62
Q

What is the action of calcium acetate (Phoslo)

A

􏰀 Binds twice as much phosphate as other Ca2+ salts
􏰀 Limits GI absorption􏰁diarrhea

63
Q

T/F. Moderate concentrations from 1 – 2.5mg/dL are much more common than severe concentrations
(

A

T

64
Q

What kind of therapy is required in severe hypophosphatemia?

A

􏰀 Intravenous therapy
* use ↓ doses in pts w/ renal dysfunction
􏰀 Oral therapy is assoc w/ osmotic diarrhea

65
Q

Osteoporosis tr

A

Biphosphonates-seen increaing bone in 3 m/ dont lie down within 30 min

Ibandronate- once a month(oral), every 3 m(inje)

Denosumab- rankl ( only works on osteoblast)