Bone disease

Question 1

features of bone

Answer 1

• load bearing
• dynamic
• self repairing

Question 2

what is bone?

Answer 2

mineralised connective tissue

Question 3

Components of bone

Answer 3

• calcium
• phosphate
• vitamin D

Question 4

parathyroid hormone actions

Answer 4

• maintains serum calcium level
• increases calcium release from bone
• reduces renal calcium excretion

Question 5

What is hypoparathyroidism?

Answer 5

low serum calcium

Question 6

primary hyperparathyroidism causes

Answer 6

• gland dysfunction e.g. tumour
• high serum calcium results

Question 7

What do both hyper- and hypoparathyroidism lead to?

Answer 7

increased bone resorption

Question 8

Vitamin D problems are usually caused by…

Answer 8

Low sunlight exposure
- housebound
- dark skinned in northern country

Poor GI absorption
-poor nutrition
- small intestinal disease leading to malabsorption

drug interactions
- some anti epileptic drugs such as carbamazepine and phenytoin

often combination of factors

Question 9

Osteromalacia - features

Answer 9

• poorly mineralised osteoid matrix
• poorly mineralised cartilage growth plate

Question 10

osteoporosis features

Answer 10

• loss of mineral and matrix
• leads to reduced bone mass

Question 11

Osteomalacia during bone formation is known as…

Answer 11

Rickets

Question 12

What is osteolomalacia related to?

Answer 12

• calcium deficiency
• serum calcium preserved at expense of bone

Question 13

osteomalacia bone effects

Answer 13

Bones bend under pressure
- ‘bow legs’
- vertebral compression in adults
bones ache to touch

Question 14

osteomalacia hypocalcaemia effects

Answer 14

• muscle weakness
• facial twitching from CNVII tapping
• carpal muscle spasm

Question 15

Osteomalacia management

Answer 15

correct cause
- malnutrition
- control GI disease
sunlight exposure
- 30 mins x 5 weekly
dietary vitamin D

Question 16

Osteoporosis is…

Answer 16

• a reduced quantity of normally mineralised bone
• an age-related change
• inevitable

Question 17

Osteoporosis risk factors

Answer 17

Age
sex - more likely in females
endocrine
- oestrogen and testosterone deficiency
- cushings syndrome
genetic
- family history
- race - Caucasian and asian women
- early menopause
patient factors
- inactivity
- smoking
- excess alcohol use
- poor dietary calcium
medicinal drugs use
- steroids
- anti-epileptics

Question 18

peak bone mass is at age…

Answer 18

24-35 years

Question 19

osteoporosis incidence in women aged 50, 70 and 80

Answer 19

50 = 15%
70 = 30%
80 = 40%

Question 20

Possible reasons why osteoporosis is more common in females

Answer 20

• males have higher peak bone mass
• oestrogeen withdrawal increases bone mass loss rate in women
• less exercise in women?

Question 21

osteoporosis effects

Answer 21

increased bone fraction risk
- particularly lone bones e.g. femur

effects on vertebrae
- height loss
- kyphosis and scoliosis
- nerve root compression = back pain

Question 22

osteoporosis lifetime risk of hip fracture >50 years of age

Answer 22

17.5% - women
6% - men

Question 23

effects following osteoporosis related hip fracture

Answer 23

20% increase in 5yr mortality
- maximal in initial 5 months

40% unable to walk unaided
60% unable to live independently

Question 24

Osteoporosis prevention

Answer 24

build maximal peak bone mass
- exercise
- high dietary calcium intake

reduce rate of bone mass loss
- continue exercise and calcium intake
- reduce hormone related effects: oestrogen hormone replacement therapy = most effective if early menopause

reduce drug related effects
- consider osteoporosis prevention drugs (bisphosphonates)

Question 25

Hormone replacement therapy - summarise

Answer 25

oestrogen only
- reduces osteoporosis risk
- increases breast cancer risk
- increases endometrial cancer risk in patients who have not had a hysterectomy
- may reduce risk of ovarian cancer
- increases DVT risk

benefit lost after HRT stops - returns to normal 5 years post treatment

Question 26

How to reduce risk of endometrial cancer risk in oestrogen therapy

Answer 26

combine with progestogen

Question 27

bisphosphonates - effectiveness

Answer 27

50% reduced risk of vertebral fracture
other risk of fracture reduced by 30-50%
benefit lost if drug discontinued
can be combines with HRT