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Flashcards in Bone Disorders Deck (57)
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1

What disease is characterised by a low bone mass causing skeletal fragility and susceptibility to fracture?

Osteoporosis

2

At what distinct sites does bone undergo remodelling?

bone remodelling units

3

What percentage of the adult skeleton is remodelled each year?

~10%

4

Briefly describe the bone remodelling cycle

- osteoclasts appear on a previously inactive surface
- resorb the bone
- replaced by osteoblasts in the cavity
- they put down osteoid that is mineralised to form new bone

5

Describe the ratio of osteoclasts to osteoblasts in osteoporosis

Osteoclasts>osteoblasts
=> more bone breakdown than formation

6

Describe the differences in micro-architecture between normal and osteoporotic bone

Osteoporotic:
- clear loss of bone
- large spaces and breaks
- breaks lead to weakened bones and fractures

Normal bone:
- thick, dense network
- small spaces
=> increased bone strength

7

At what age do humans achieve their peak bone density?

Late 20s

8

Menopause causes slower age related bone loss. TRUE/FALSE?

FALSE
Menopause causes a period of accelerated bone loss

9

What are the most common fracture sites in osteoporosis?

Neck of femur
Vertebral body
Distal radius
Humeral neck

10

An older lady with osteoporosis falling onto an outstrectched hand is most likely to sustain what type of fracture?

Colles fracture

11

Wedge fractures of the spine can result in what curvature forming?

Thoracic Kyphosis

12

What scan is used to measure bone density?

DEXA scan

13

What bones are measured in a DEXA scan to assess bone density and why?

Hip
L1-L4
- as these are most prone to fracture -

14

Describe the difference between a T score and a Z score on the DEXA scan

T score = bone density compared to young adult population average

Z score = compared to population average of the same age as the patient

15

In what situation would only a Z score be considered ni a DEXA scan?

If the patient was <20 years old

16

How are DEXA results interpreted?

Normal if less than 1 standard deviation (SD) below the young adult average

Osteopenia if between 1 and 2.5 standard deviations below the young adult average

Osteoporosis if 2.5 or more standard deviations below

17

What does 1 standard deviation of seperation in a DEXA scan indicate in terms of fracture risk?

Lowering by 1 SD doubles fracture risk

18

What type of patients should be referred for a DEXA scan?

> 50 with low trauma fracture

If at increased risk:
e.g. > 10% risk of fracture over 10 years

19

What calculators are used to measure fracture risk in osteoporosis?

FRAX or Qfracture

20

The new SIGN guideline is no longer based on treating patients in terms of their mineral bone density. What is it more concerned about?

Fracture Risk

21

Give an example of a risk factor for a fragility fracture that is non-modifiable

- Age
- Gender
- Ethnicity
- Previous #
- FHx
- Menopause ≤ 45 years

22

What risk factors for fragility fractures are modifiable?

- BMD
- Alcohol
- Weight/Physical inactivity
- Smoking
- Drugs (e.g. steroids)

23

What biochemical investigations should be considered in a patient who you are suspecting has osteoporosis

U+Es
LFTs
FBC and Plasma Viscosity
TSH

Consider:
- Coeliac antibodies
- 25OH Vitamin D
- Parathyroid hormone

24

What endocrine conditions are secondary causes of osteoporosis?

hyperthyroidism
hyperparathyroidism
Cushing’s disease

25

What GI conditions cause secondary osteoporosis?

coeliac disease
IBD
chronic liver disease
chronic pancreatitis

26

What respiratory conditions are linked to the development of secondary osteoporosis?

CF
COPD

27

What lifestyle advice is used in management of osteoporosis?

- High intensity strength training
- Low-impact weight-bearing exercise
- Avoidance of excess alcohol/smoking
- Fall prevention

28

How much calcium should post-menopausal women aim to eat per day in order to reduce their fracture risk?

1000 mg calcium (3-4 portion calcium rich foods)

29

What non-dairy foods are considered sources of calcium?

Non-dairy sources include
- bread and cereals (fortified)
- fish with bones, nuts,
- green vegetables, beans

30

What drug treatments are often given in osteoporosis?

- Calcium & Vit D supplements
- Bisphosphonates
- Denosumab (monoclonal antibody)
- Teriparatide (Parathyroid hormone anabolic agent)
- HRT
- SERMS (Selective Estrogen Receptor Modulators)
- Testosterone