Bones Flashcards
1
Q
5 common osteoporotic #s
A
hip NOF vertebral body distal radius humeral neck
2
Q
cells that cause bone resorption
A
osteoclasts
3
Q
cells that cause bone formation
A
osteoblasts
4
Q
function - bone mineralisation
A
osteoid
5
Q
drugs that can enhance osteoporosis progression
A
steroids aromatase inhibitors (breast cancer Rx)
6
Q
bone loss usually starts at this age
A
40yo
7
Q
DEXA scan measures your __
and so predicts your __ risk independent of other risk factors
A
bone mineral density #
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%
9
Q
DEXA result if you are osteopenic
A
> 1 but <2.5SD less than the mean
10
Q
DEXA result if you are osteoporotic
A
> =2.5 SD less than mean
11
Q
severe osteoporosis is defined as BMD ___ and ___
A
> =2.5SD less than mean
fragility #
12
Q
Bence Jones proteins are found if you have __
A
multiple myeloma
13
Q
Rx for osteoporosis =
A
Calcium and vitamin D supplements biphosphonates zoledronic acid denosumab strontium ranelate teriparatide
14
Q
calcium and vitamin D supplements decrease the risk of ___ # if deficiency risk
A
non-vertebral
15
Q
dont give Ca2+ supplements within 2hrs of ___
A
PO biphosphonates
16
Q
2 examples of biphosphonates
A
alendronate
risendronate
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%
18
Q
long term adverse affects of biphosphonates
A
jaw osteonecrosis
oesophagus cancer
atypical #s
therefore - consider a bone holiday
19
Q
zoledronic acid dose route and duration
A
1/yr IV for 3 yrs
20
Q
if get acute phase reaction with 1st infusion of zoledronic acid = give ___
A
paracetamol
21
Q
side effects of denosumab
A
hypoCa2+
eczema
cellulitis
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
23
Q
route of denosumab and how often its given
A
S/C injection
6 monthly
24
Q
denosumab is not contra-indicated in ___
A
severe renal impairment
25
recombinant PTH that stimulates bone growth =
given in >65yo with t 2#s
or 55-64yo with t 2#s
teriparatide
26
when to consider antiresorptive treatment in osteoporosis
if t <=-2.5
| ongoing steroid Rx >=3months/prevalent vert# and t <=-1.5
27
how steroids increase osteoporosis progression =
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
28
abnormal osteoclast activity => increased osteoblast activity =
Paget's disease
29
Paget's affects these bones
long bones, pelvis, lumbar sppine and skull predominantly
30
Paget's can rarely lead on to cause
osteosarcoma
31
presentation of Paget's
bone pain, deformity, deafness, compression neuropathies
32
diagnosis of Pagets (3 Ix)
XR
isotope scan
normal LFTs but raised ALP
33
treat paget's with ___ or __ if 1st line doesnt reduce bone pain
analgesics
| biphosphonates
34
osteogenesis imperfecta is caused by mutations of ___
| most mode of inheritance =
type 1 collagen genes (COL1A1/2)
| auto dom
35
very sever form of osteogenesis imperfecta =
type 3 and 4
36
type of osteogenesis imperfecta that is neonatally lethal
2
37
ass. with blue sclera +/ dentinogenesis imperfecta
osteogenesis imperfecta
38
Rx for osteogenesis imperfecta
```
#fixation, Sx for deformities
biphosphonates once growth plates have fused
```
39
Ca2+ > ___ in PT gland > ___ PTH to skeleton (=>____) and GI tract (=>___)
CaSR
decreased
resorption
absorption
40
___(sun > cholecaldiferol/D3(___)>25 OH vit D (___) >_____>PTH, skeleton, GI, kidney
dehydro-cholesterol
liver
kidney
1-25OH vit D
41
acute hypercalcaemia s+s
| may =>
```
thirst
dehydration
polyuria
confusion
=> nephrogenic DI
```
42
chronic hypercalcaemia s+s
```
myopathy
osteopenia
#s
depression
hbp
pancreatitis, GI ulcers, renal stones
```
43
hypercalcaemia causes albumin and urea levels to be ___ if dehydrated
raised
44
blood results if primary/tertiary hyperPT
albumin normal/low
PTH normal/raised
PO4 low or normal
raised urine Ca2+
45
FHH caused urine calcium levels to be ___
low
46
hypercalcaemia related to bone pathology blood results
albumin normal/low
suppressed PTH
raised PO4
47
if ALP is raised and suspect bone pathology it could be _/_/_
thyrotoxicosis
bone metastases
sarcoidosis
48
if ALP is low and suspect bone pathology it could be _/_/__
myeloma
vitamin D excess
mild-alkali syndrome - sarcoid/thyrotoxicosis/increased bicarbonate
49
causes of hypercalcaemia
```
primary and tertiary hyperPT
malignancy
vit D/thiazides
granulomatous diseases
FHH
high bone turnover
```
50
FHH stands for ___
familial hypocalciuric hypercalcaemia
51
diagnosis of primary hyperPT blood results -
increased serum Ca2+ and PTH (or inapp normal)
| increased urine calcium excretion
52
Ix and results for hypercalcaemia of malignancy
increased serum Ca2+ and ALP
XR
isotope bone scan
53
Rx of acute hypercalcaemia
```
immediate = fluids (0.9% saline)
loop diuretics
biphophonates single dose
steroids - if sarcoids
chemo in malig
```
54
imaging used for the PT =
Sestamibi scan
55
treatment that can be used for tertiary hyperPT/PT carcinoma
cinacalcet
56
Indications for a parathyroidectomy in primary hyperparathyroidism:
end organ damage
very high Ca2+ (>2.85mmol/l)
<50yo/fit
eGFR <60
57
___ hyperparathyroidism = PT is overactive
PTH and Ca2+ =
eg. of a cause
primary
both raised
adenoma of PT
58
2ndry hyperPT =
| Ca2+ and PTH =
physiological response to low Ca2+ levels
| Ca2+ low and PTH raised
59
tertiary hyperPT =
| Ca2+ and PTH =
PT autonomous after years of 2ndry
| both raised
60
genetic syndromes associated with hypercalcaemia
MEN1/2 (present young)
| FHPT
61
FHH mode of inheritance
| mutation =
auto dom
deactivating mutation in CaSR
usually benign/asympt
62
s+s of hypocalcaemia
```
paraesthesia
muscle cramps/tetany
muscle weakness
fatigue
fits
broncho/laryngospasm
Chovstek's sign (tap CNVII)
Trousseau sign (carpopedal spasm)
QT prolonged
```
63
emergency Rx for hypocalcaemia
IV Ca2+ gluconate (10ml 10% over 10 mins in 50ml saline/dextrose)
64
causes of hypoPT
```
DiGeorge
Sx/radio/malig
AI
hypoMg2+ (PPI/alcoholic)
idiopathic
```
65
3 options for long term management of hypocalcaemia
>1-2g Ca2+ supplements od
vit D (1alpha calcidol 0.5-1mcg)
depot injection cholecalciferol 300,000U/6months
66
in Mg2+ deficiency intracellular Ca2+ is high/low? because ___
high
| Ca2+ release from cells is dependent on Mg2+
67
causes of hypomagnesaemia
```
alcohol
thiazides and PPIs
GI illness
pancreatitis
malabsorption
```
68
in hypomagnesaemia ___ is inhibited, skeletal and muscle receptors are less sensitive to ___
PTH release
| PTH
69
if this mineral is also low in hypocalcaemia then it needs supplemented as well
Mg2+
70
pseudohypoparathyroidism is caused by the genetic defect ____
__Ca2+ and ___ PTH (as there is PTH ___)
GNAS1 gene defect - dysfunction of Gs alpha subunit
| low Ca2+ and high PTH - PTH resistance
71
symptoms and signs of pseudohypoPT
```
bone abnormalities (Albright's hereditary osteodystrophy)
obesity
4th MC brachydactyly
S/C calcification
IQ low
```
72
pseudo-pseudohypoPT = all of pseudo symptoms but __
normal Ca2+
73
Looser Zones on XR =
Pseudo#s: wide, transverse lucencies traversing part way through a bone, usually at right angles to the involved cortex
sign of osteomalacia/rickets
74
in osteomalacia Ca2+, PO4-, ALP, vit D, PTH levels
Ca2+, PO4 3- = low
ALP = high
vit D = low
PTH = high
75
Rx for osteomalacia
```
D3 tablets (3200U/day for 12 wks then 400-800/day)
calcitriol
alfacalcidol
```
76
X-linked hypophosphataemia aka
vit D resistant rickets
77
FGF23 regulates ___ levels which is secreted by ___ in response to calcitriol
Phosphate plasma levels
| osteocytes
78
in pagets _+_+_ are normal but __ is very high
Ca2+, PTH and phosphate
| ALP v raised
79
vertebrae looks fish shaped =
biconcave vertebral #
80
T score =
BMD compared to young adult population
81
Z-score =
compares BMD to same sex and age - shows if increased loss for age
82
anabolic drug used if severe osteoporosis and vertebral # risk
teraparatide
83
mothy bone (lytic lesions) indicates
metastatic bone disease
84
5 cancers likely to spread to bone
```
breast
lung
bowel
renal
prostate
```
85
coarse trabecullar pattern and cortical thickening
| hot and tender =
Paget's
86
marker of remission in Paget's
ALP normalises from being high
87
PTH effects on bone and kidneys
increase resorption and Ca2+ release
| increase reabsorption and excretion of phosphate in urine
88
active form of vitamin d
1,25 - dihydroxycholecalciferol
89
stones bones moans and abdominal groans =
hypercalcaemia
90
facial muscles twitch when tap CN VII
Chvosteks sign (hypoCa2+)
91
bp cuff inflation causes tetany in hand and wrist
Trousseaus sign (hypocalcaemia)
92
genetic abnormality that causes PTH resistance
pseudohypoPT
93
craniotabes=
soft skull bones at birth (sign of rickets)
94
___ from the hypothalamuc inhibits GH release from ant pit
somatostatin
95
A SERM - selective oestrogen receptor modulator for postmenopausal women with osteoporosis
raloxifene
