Bones Flashcards

1
Q

5 common osteoporotic #s

A
hip
NOF
vertebral body
distal radius
humeral neck
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2
Q

cells that cause bone resorption

A

osteoclasts

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3
Q

cells that cause bone formation

A

osteoblasts

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4
Q

function - bone mineralisation

A

osteoid

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5
Q

drugs that can enhance osteoporosis progression

A
steroids
aromatase inhibitors (breast cancer Rx)
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6
Q

bone loss usually starts at this age

A

40yo

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7
Q

DEXA scan measures your __

and so predicts your __ risk independent of other risk factors

A
bone mineral density
#
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8
Q

fracture risk calculator validated in the UK =

refer on for a DEXA if ___

A

Q fracture

10yr risk for an osteoporotic # is >= 10%

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9
Q

DEXA result if you are osteopenic

A

> 1 but <2.5SD less than the mean

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10
Q

DEXA result if you are osteoporotic

A

> =2.5 SD less than mean

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11
Q

severe osteoporosis is defined as BMD ___ and ___

A

> =2.5SD less than mean

fragility #

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12
Q

Bence Jones proteins are found if you have __

A

multiple myeloma

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13
Q

Rx for osteoporosis =

A
Calcium and vitamin D supplements
biphosphonates
zoledronic acid
denosumab
strontium ranelate
teriparatide
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14
Q

calcium and vitamin D supplements decrease the risk of ___ # if deficiency risk

A

non-vertebral

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15
Q

dont give Ca2+ supplements within 2hrs of ___

A

PO biphosphonates

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16
Q

2 examples of biphosphonates

A

alendronate

risendronate

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17
Q

biphosphonate mechanism of action =

A

anti resorptive
analogues of pyrophosphate that are absorbed onto bone in matrix > ingested by osteoclasts > cell deth and resorption sites are filled by new bone > BMD increases by 5-8%

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18
Q

long term adverse affects of biphosphonates

A

jaw osteonecrosis
oesophagus cancer
atypical #s
therefore - consider a bone holiday

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19
Q

zoledronic acid dose route and duration

A

1/yr IV for 3 yrs

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20
Q

if get acute phase reaction with 1st infusion of zoledronic acid = give ___

A

paracetamol

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21
Q

side effects of denosumab

A

hypoCa2+
eczema
cellulitis

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22
Q

Denosumab mechanism of action

A

monoclonal Ig that binds to RANKL > prevents activation of RANK (its receptor) > inhibits development and activity of osteoclasts, decreases resorption and increases BMD

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23
Q

route of denosumab and how often its given

A

S/C injection

6 monthly

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24
Q

denosumab is not contra-indicated in ___

A

severe renal impairment

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25
Q

recombinant PTH that stimulates bone growth =
given in >65yo with t 2#s
or 55-64yo with t 2#s

A

teriparatide

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26
Q

when to consider antiresorptive treatment in osteoporosis

A

if t <=-2.5

ongoing steroid Rx >=3months/prevalent vert# and t <=-1.5

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27
Q

how steroids increase osteoporosis progression =

A

reduce osteoblast activity and lifespan
suppress replication of osteoblast precursors
reduce Ca2+ absorption from gut
indirectly inhibit gonadal and adrenal steroid production
increase Ca2+ renal excretion
increase PTH sensitivity and secretion => increase osteoclast activity

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28
Q

abnormal osteoclast activity => increased osteoblast activity =

A

Paget’s disease

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29
Q

Paget’s affects these bones

A

long bones, pelvis, lumbar sppine and skull predominantly

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30
Q

Paget’s can rarely lead on to cause

A

osteosarcoma

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31
Q

presentation of Paget’s

A

bone pain, deformity, deafness, compression neuropathies

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32
Q

diagnosis of Pagets (3 Ix)

A

XR
isotope scan
normal LFTs but raised ALP

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33
Q

treat paget’s with ___ or __ if 1st line doesnt reduce bone pain

A

analgesics

biphosphonates

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34
Q

osteogenesis imperfecta is caused by mutations of ___

most mode of inheritance =

A

type 1 collagen genes (COL1A1/2)

auto dom

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35
Q

very sever form of osteogenesis imperfecta =

A

type 3 and 4

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36
Q

type of osteogenesis imperfecta that is neonatally lethal

A

2

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37
Q

ass. with blue sclera +/ dentinogenesis imperfecta

A

osteogenesis imperfecta

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38
Q

Rx for osteogenesis imperfecta

A
#fixation, Sx for deformities
biphosphonates once growth plates have fused
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39
Q

Ca2+ > ___ in PT gland > ___ PTH to skeleton (=>____) and GI tract (=>___)

A

CaSR
decreased
resorption
absorption

40
Q

___(sun > cholecaldiferol/D3(___)>25 OH vit D (___) >_____>PTH, skeleton, GI, kidney

A

dehydro-cholesterol
liver
kidney
1-25OH vit D

41
Q

acute hypercalcaemia s+s

may =>

A
thirst 
dehydration
polyuria
confusion
=> nephrogenic DI
42
Q

chronic hypercalcaemia s+s

A
myopathy
osteopenia
#s
depression
hbp
pancreatitis, GI ulcers, renal stones
43
Q

hypercalcaemia causes albumin and urea levels to be ___ if dehydrated

A

raised

44
Q

blood results if primary/tertiary hyperPT

A

albumin normal/low
PTH normal/raised
PO4 low or normal
raised urine Ca2+

45
Q

FHH caused urine calcium levels to be ___

A

low

46
Q

hypercalcaemia related to bone pathology blood results

A

albumin normal/low
suppressed PTH
raised PO4

47
Q

if ALP is raised and suspect bone pathology it could be //_

A

thyrotoxicosis
bone metastases
sarcoidosis

48
Q

if ALP is low and suspect bone pathology it could be //__

A

myeloma
vitamin D excess
mild-alkali syndrome - sarcoid/thyrotoxicosis/increased bicarbonate

49
Q

causes of hypercalcaemia

A
primary and tertiary hyperPT
malignancy
vit D/thiazides
granulomatous diseases
FHH
high bone turnover
50
Q

FHH stands for ___

A

familial hypocalciuric hypercalcaemia

51
Q

diagnosis of primary hyperPT blood results -

A

increased serum Ca2+ and PTH (or inapp normal)

increased urine calcium excretion

52
Q

Ix and results for hypercalcaemia of malignancy

A

increased serum Ca2+ and ALP
XR
isotope bone scan

53
Q

Rx of acute hypercalcaemia

A
immediate = fluids (0.9% saline)
loop diuretics
biphophonates single dose
steroids - if sarcoids
chemo in malig
54
Q

imaging used for the PT =

A

Sestamibi scan

55
Q

treatment that can be used for tertiary hyperPT/PT carcinoma

A

cinacalcet

56
Q

Indications for a parathyroidectomy in primary hyperparathyroidism:

A

end organ damage
very high Ca2+ (>2.85mmol/l)
<50yo/fit
eGFR <60

57
Q

___ hyperparathyroidism = PT is overactive
PTH and Ca2+ =
eg. of a cause

A

primary
both raised
adenoma of PT

58
Q

2ndry hyperPT =

Ca2+ and PTH =

A

physiological response to low Ca2+ levels

Ca2+ low and PTH raised

59
Q

tertiary hyperPT =

Ca2+ and PTH =

A

PT autonomous after years of 2ndry

both raised

60
Q

genetic syndromes associated with hypercalcaemia

A

MEN1/2 (present young)

FHPT

61
Q

FHH mode of inheritance

mutation =

A

auto dom
deactivating mutation in CaSR
usually benign/asympt

62
Q

s+s of hypocalcaemia

A
paraesthesia
muscle cramps/tetany
muscle weakness
fatigue
fits
broncho/laryngospasm
Chovstek's sign (tap CNVII)
Trousseau sign (carpopedal spasm)
QT prolonged
63
Q

emergency Rx for hypocalcaemia

A

IV Ca2+ gluconate (10ml 10% over 10 mins in 50ml saline/dextrose)

64
Q

causes of hypoPT

A
DiGeorge
Sx/radio/malig
AI
hypoMg2+ (PPI/alcoholic)
idiopathic
65
Q

3 options for long term management of hypocalcaemia

A

> 1-2g Ca2+ supplements od
vit D (1alpha calcidol 0.5-1mcg)
depot injection cholecalciferol 300,000U/6months

66
Q

in Mg2+ deficiency intracellular Ca2+ is high/low? because ___

A

high

Ca2+ release from cells is dependent on Mg2+

67
Q

causes of hypomagnesaemia

A
alcohol
thiazides and PPIs
GI illness
pancreatitis
malabsorption
68
Q

in hypomagnesaemia ___ is inhibited, skeletal and muscle receptors are less sensitive to ___

A

PTH release

PTH

69
Q

if this mineral is also low in hypocalcaemia then it needs supplemented as well

A

Mg2+

70
Q

pseudohypoparathyroidism is caused by the genetic defect ____
__Ca2+ and ___ PTH (as there is PTH ___)

A

GNAS1 gene defect - dysfunction of Gs alpha subunit

low Ca2+ and high PTH - PTH resistance

71
Q

symptoms and signs of pseudohypoPT

A
bone abnormalities (Albright's hereditary osteodystrophy)
obesity
4th MC brachydactyly
S/C calcification
IQ low
72
Q

pseudo-pseudohypoPT = all of pseudo symptoms but __

A

normal Ca2+

73
Q

Looser Zones on XR =

A

Pseudo#s: wide, transverse lucencies traversing part way through a bone, usually at right angles to the involved cortex
sign of osteomalacia/rickets

74
Q

in osteomalacia Ca2+, PO4-, ALP, vit D, PTH levels

A

Ca2+, PO4 3- = low
ALP = high
vit D = low
PTH = high

75
Q

Rx for osteomalacia

A
D3 tablets (3200U/day for 12 wks then 400-800/day)
calcitriol
alfacalcidol
76
Q

X-linked hypophosphataemia aka

A

vit D resistant rickets

77
Q

FGF23 regulates ___ levels which is secreted by ___ in response to calcitriol

A

Phosphate plasma levels

osteocytes

78
Q

in pagets ++_ are normal but __ is very high

A

Ca2+, PTH and phosphate

ALP v raised

79
Q

vertebrae looks fish shaped =

A

biconcave vertebral #

80
Q

T score =

A

BMD compared to young adult population

81
Q

Z-score =

A

compares BMD to same sex and age - shows if increased loss for age

82
Q

anabolic drug used if severe osteoporosis and vertebral # risk

A

teraparatide

83
Q

mothy bone (lytic lesions) indicates

A

metastatic bone disease

84
Q

5 cancers likely to spread to bone

A
breast
lung
bowel
renal 
prostate
85
Q

coarse trabecullar pattern and cortical thickening

hot and tender =

A

Paget’s

86
Q

marker of remission in Paget’s

A

ALP normalises from being high

87
Q

PTH effects on bone and kidneys

A

increase resorption and Ca2+ release

increase reabsorption and excretion of phosphate in urine

88
Q

active form of vitamin d

A

1,25 - dihydroxycholecalciferol

89
Q

stones bones moans and abdominal groans =

A

hypercalcaemia

90
Q

facial muscles twitch when tap CN VII

A

Chvosteks sign (hypoCa2+)

91
Q

bp cuff inflation causes tetany in hand and wrist

A

Trousseaus sign (hypocalcaemia)

92
Q

genetic abnormality that causes PTH resistance

A

pseudohypoPT

93
Q

craniotabes=

A

soft skull bones at birth (sign of rickets)

94
Q

___ from the hypothalamuc inhibits GH release from ant pit

A

somatostatin

95
Q

A SERM - selective oestrogen receptor modulator for postmenopausal women with osteoporosis

A

raloxifene