1: Metabolic Bone Disease Flashcards
(129 cards)
1
Q
What is osteoporosis
A
condition where there is a decrease bone density leading to decrease bone strength
2
Q
Which age group is most likely to develop osteoporosis
A
Elderly
3
Q
In which gender is osteoporosis more common
A
Females (4:1)
4
Q
What is the typical demographic affected by osteoporosis
A
Post-menopausal females
5
Q
How can the aetiology of osteoporosis be divided
A
Primary
Secondary
6
Q
What is type I primary osteoporosis
A
Post-menopausal osteoporosis
7
Q
Explain briefly the pathophysiology of type I osteoporosis
A
- Oestrogen activates osteoblasts and inhibits osteoclasts
- At menopause oestrogen decreases
- Drop in oestrogen increases osteoclast activity and decreases osteoblast activity
8
Q
What is type II primary osteoporosis
A
Osteoporosis due to underlying disorder
9
Q
How can the aetiology of secondary osteoporosis be divided
A
- Iatrogenic
- Endocrine
- Other
10
Q
What are 3 iatrogenic causes of secondary osteoporosis
A
- PPI’s
- Corticosteroids
- Anti-epileptics
11
Q
What 3 drugs can cause osteoporosis
A
- PPI’s
- Corticosteroids
- Anti-epileptics
12
Q
What are the 5 endocrine causes of osteoporosis
A
- Hyperparathyroidism
- Renal osteodystrphy
- Hyperthyroidism
- Cushing’s disease
- Hypogonadism
13
Q
Aside from endocrine and iatrogenic causes, what else may cause secondary osteoporosis
A
- Alcohol abuse
- Immobilisation
14
Q
What is a mneumonic to remember risk factors for osteoporosis
A
SHATTERED
15
Q
what are the risk factors for osteoporosis
A
Steroid use Hyperparathyroidism, hyperthyroidism, hypercalciuria Alcohol abuse Thin (BMI <18.5) Testosterone low Early menopause Renal or liver failure Erosive or inflammatory disease Diet malnutrition, T1DM
16
Q
How will osteoporosis present clinically
A
asymptomatic. First presentation is typically with a fragility fracture
17
Q
Order the following in most likely region to suffer from an osteoporotic fracture
A
Vertebral > Femoral neck > Colle’s fracture > long bone
18
Q
how may vertebral fractures present
A
- Acute back pain
- If multiple fractures may present with progressive shortening and thoracic kyphosis
19
Q
if trabecular bone is affected , what type of fracture is more common
A
Vertebral
20
Q
in which gender are trabecular fractures more common and why
A
Females. As males trabecular bone remains stable in time, whereas females loose trabecular bone with age
21
Q
if cortical bone is affected, what fractures are more likely
A
Long bone
22
Q
what investigations may be performed following an osteoporotic fracture
A
- X-Ray
- Fracture assessment tool (FRAX, Q Fracture)
- DEXA scan
- Bone profile
23
Q
what tool is used to assess risk of fracture
A
FRAX (fracture risk assessment tool)
24
Q
who is a FRAX score calculated for
A
All women >65y
All men >75y
Younger patients in presence of risk factors
25
what does FRAX score calculate
Individuals risk of osteoporotic fragility fracture in 10y
26
what age range is FRAX score suitable for
40-90
27
if FRAX shows an intermediate score what should be done
Bone mineral density score
28
If FRAX shows a good score, what should be done
No treatment
29
If FRAX shows a poor score, what should be done
Treat
30
Aside from FRAX, what is another tool used to assess risk of osteoporotic fracture
QFracture
31
what age can QFracture be used for
30-99
32
If a individual had their FRAX score calculated with bone mineral density and scores the following what should be done
a. low risk
b. intermediate risk
c. high risk
a. do not treat
b. consider treatment
c. treat
33
when should the FRAX score be re-assessed
- After 2 years if individual was in 'consider treatment' but did not opt to
- Change in person's risk factors
34
What is used to assess bone mineral density
DEXA scan
35
what are 6 indications for DEXA scan
1. Women >65y with one or more risk factors of osteoporosis
2. Women <65y with two or more RF for osteoporosis
3. Low trauma fracture
4. Fragility fracture
5. Starting long-term prednisolone
6. Bone remodelling disorder
36
What dose of prednisolone should individuals be DEXA scanned before giving
>5mg/d for 3m
37
What group of patients do not need a DEXA scan before treating
>75y with two or more of the following: rheumatoid arthritis, alcohol abuse, FHx
38
What does a DEXA scan provide
T score
39
What is the T score
Provides number standard deviations individual is away from average bone mineral density of a 30y male
40
what does T>0 indicate
Better than reference
41
What does T: 0 to -1 indicate
In top 84% (normal healthy bone)
42
What does T: -1 to -2.5 indicate
Osteopenia
43
What does T: less than -2.5 indicate
Osteoporosis
44
What is a Z score
Bone mineral density compared to individual the same age
45
Why may a bone profile be requested in osteoporosis
To identify hyperparathyroidism, or other diseases.
46
What is first-line management for osteoporosis
lifestyle management
47
What 6 pieces of lifestyle advice would you provide someone with osteoporosis
1. Smoking cessation
2. Limit alcohol to <2 units
3. Tai chi
4. Weight bearing exercises
5. Falls prevention program
6. Calcium and vitamin D supplementation
48
Why is tai chi offered
To improve balance and help reduce falls
49
when are calcium and vitamin D supplementation offered
If evidence of deficiency
50
what is second-line management for osteoporosis
Aledronate (bisphosphonate)
51
what dose of alendronate is offered
10mg/d
52
what is a contraindication to aledronate
eGFR <35
53
what other bisphosphonates may be used if the individual is intolerant to alendronate
risedrontate, etidronate
54
What is third-line for management of osteoporosis
strontium ranelate
55
why is strontium ranelate not first line
as it increases the risk of VTE and cardiovascular disease
56
what are the requirements for strontium ranelate
>60Y and T score -3.5 or less
57
what is fourth-line for osteoporosis
Raloxifene
58
what is raloxifene
selective oestrogen receptor modulator
59
what is the benefit of raloxifene
it does not increase the risk of breast cancer
60
what is the main disadvantage of raloxifene
increases VTE risk
61
what is the criteria for raloxifene
Women >60y with a T score of less than -3.5
62
what is 5th line management for osteoporosis
denosumab
63
what is denosumab
RANKL monoclonal antibody
64
how is denosumab given
subcutaneous injection twice a year
65
what is the main complication of osteoporosis
fragility fractures
66
What are the 4 fat soluble vitamins
A,D,E,K
67
How can the causes of vitamin D deficiency be divided
- Poor intake
- Malabsorption
- Poor metabolism
68
What are 3 causes of vitamin D deficiency due to poor intake
- Dark skin (reduces UV absorption)
- Poor exposure to UVB
- Poor dietary intake
69
What are 3 causes of vitamin D deficiency due to malabsorption
Coeliac
Gastrectomy
Cystic fibrosis
70
Why does cystic fibrosis cause malabsorption of vitamin D
Due to reduced absorption of fat soluble vitamins
71
What are 4 causes of defective metabolism that lead to vitamin D deficiency
- CYP450 inducers
- Liver cirrhosis
- Anticonvulsants
- Renal disease
72
Define osteoporosis
decreased bone mineral density
73
Define osteopenia
decreased bone strength but less severe than osteoporosis
74
What is T score
compares individuals mean mineral bone density to mean peak mass of a healthy young adult
75
What T score indicates osteopenia
-1 to -2.5
76
What T score indicates osteoporosis
less than -2.5
77
What is the Z score
compares individuals mean mineral bone density to someone of the same age and gender
78
What are 4 ways osteoporosis may present
- Asymptomatic
- Fragility fracture
- Progressive shortening and thoracic kyphosis
- Acute back pain
79
What are 4 complications of osteoporosis
- Vertebral fracture
- Colle's fracture
- NOF fracture
- Chronic pain syndrome
80
What are 3 structural consequences on bone in osteoporosis
1. Fewer trabeculae
2. Thinner cortical bone
3. Widening of haversian canals
81
What is osteomalacia
insufficient mineralisation of bone
82
what is the difference between osteomalacia and ricket's disease
it is termed osteomalacia if it occurs after epiphysis have fused. And, ricket's if before.
83
how can the aetiology of osteomalacia be divided
vitamin D dependent and vitamin D independent
84
how can causes of vitamin D deficiency be divided
1. Insufficient intake
2. Malabsorption
3. Decreased metabolism
85
how can vitamin D independent causes of osteomalacia be divided
- Phosphate deficiency
- Medication
- Defects in renal tubule
function
86
what are two defects in renal tubule function that may lead to osteomalacia
Fanconi's syndrome
| Renal tubule acidosis
87
What are 3 medications that could cause osteomalacia
Bisphosphonates
Aluminum
Fluoride
88
How will osteomalacia present
- Bone pain
- Pathological fracture
- Proximal myopathy
89
What does proximal muscle weakness cause in osteomalacia
Waddling gait
90
Explain how renal disease can lead to renal osteodystrophy
- Renal dysfunction causes an inability to hydroxylate vitamin D to it's active form.
- Decreased vitamin D means insufficient absorption of calcium from the gut
- Calcium deficiency causes secondary hyperparathyroidism
- Increased PTH results in increased bone re-asborption
91
Explain how phosphate deficiency causes osteomalacia
Decreased phosphate in the blood stream and hence available to form bone matrix
92
What is first-line investigation of osteomalacia
Bone Profile
93
What may be seen on bone profile in osteomalacia
- Hypocalcaemia
- Hypophosphataemia
- Hyperparathyroidism
- Low vitamin D
- Raised ALP
94
What is second-line investigation of osteomalacia
X-ray
95
What finding on x-ray is pathognomic of osteomalacia
Looser's pseudofractures
96
what are looser's pseudo fractures
Sclerotic lines perpendicular to cortical margins
97
which 3 places are looser's pseudo fractures most common
- Lateral border of scapula
- Inferior femoral neck
- Medial femoral shaft
98
what is first-line management for osteomalacia
Vitamin D and Calcium Supplementation
99
if individual is dietary vitamin D deficient what should they be offered
Vitamin D3
100
If individual has vitamin D deficiency due to hepatic disease, what form should they be offered
Ergocalciferol (Vitamin D2)
101
what is the dose of ergocalciferol offered in hepatic disease
40,000 IU (1mg/day)
102
if an individual has vitamin D deficiency due to renal disease what two forms can they be offered
1. Alfacalcidiol (vitamin D2)
| 2. Calcitriol
103
what is alfacalcidiol
1a hydroxyvitamin D3 (it has been hydroxylated once, so therefore only relies on liver to hydroxylate it a second time)
104
what dose of alfacalcidiol is used
250mg/OD
105
what is calcitriol
1,25 (OH) hydroxy vitamin D
106
what dose of calcitriol is used
250mg/OD
107
what could be used to increase serum calcium concentration as a second line
Calcium carbonate (1-2g/day)
108
What is Paget's disease also referred to
Osteitis deformans
109
What is Paget's disease
Increase bone turnover in focal parts of the skeleton associated with increased osteoblast and osteoclast activity causing resultant remodelling, enlargement, deformity and weakness
110
What is a risk-factor for Paget's Disease
Age. Typically onsets >55y
| Male
111
What are two risk factors for Paget's disease
FHx
| Northern latitude
112
What % of patient's with paget's disease experience symptoms
10-30%
113
If symptoms, what is commonly experienced
Bone pain
114
If untreated, what are two severe presentations of Paget's disease
Frontal Bossing
| Bowing of the tibia
115
What is the stereotypical presentation of paget's disease
Old male with isolated raised ALP
116
Explain pathology of Paget's disease
Increased RANKL signalling increases NF-KB activity in osteoclasts. This increases osteoblast activity resulting in formation of dis-organised woven bone
117
What are the 3 phases of bone remodelling in Paget's disease
1. Lytic
2. Lytic and plastic
3. Sclerotic
118
What is the lytic phase
Increased osteoclast activity - increase bone reabsorption
119
What is the lytic and blastic phase
Increased osteoclast activity is associated with an increase in osteoblast activity
120
What is sclerotic phase
Decrease in both osteoblast and clast activity
121
What are 2 investigations of Paget's disease
Bone profile
| X-ray
122
What will be seen on bone profile in Paget's disease
Isolated raised ALP
123
How will bone appear on x-ray in Paget's disease
- Deformed bone with sclerotic and osteolytic lesions
| - Thickened cortical bone
124
How is Paget's disease managed
1. Analgesia (NSAIDs)
| 2. Bisphosphonates
125
What bisphosphonates are offered for Paget's disease
Oral riserdrontate
| IV zoledronate
126
What are 4 complications of Paget's disease
Deafness
Sarcoma
Fractures
High output cardiac failure
127
Why may Paget's disease cause deafness
Due to enlargement of the skull trapping cranial nerve
128
What are 4 most common sites of Paget's disease to assert
- Skull
- Vertebrae
- Pelvis
- Long bones
129
Why might paget's disease cause high output cardiac failure
due to increased vascularity required by bone. (It is a rare complication)
