Bone Disorders

Question 1

what is osteoporosis

Answer 1

progressive systemic skeletal disease characterised by low bone mass and micro architectural deterioration of bone tissue with subsequent increase in bone fragility and susceptibility to fracture

Question 2

where does bone remodelling occur

Answer 2

at bone remodelling units

Question 3

what is the process of bone remodelling

Answer 3

osteoclasts resorb the bone
osteoclasts are replaced by osteoblasts which fill the cavity by putting down osteoid that is mineralised to form new bone

Question 4

what causes osteoporosis

Answer 4

relative or absolute increase in resorption over formation that leads to bone loss (more osteoclast than blast activity)

Question 5

what architechtural changes occur in osteoporosis

Answer 5

decrease in trabecular thickness and connections between vertical trabeculae

Question 6

what causes peak bone mass

Answer 6

genetics, body weight, sex hormones, diet, exercise

Question 7

what causes bone loss

Answer 7

sex hormone deficiency 
body weight 
genetics 
diet 
immobility 
diseases 
drugs- glucocorticoids, aromatase inhibitors

Question 8

how do the dexa scans work

Answer 8

compares your bone score with what is should have been at its best as with average for young adult reference

Question 9

what are the parameters for DEXA scans

Answer 9

Normal : BMD within 1 SD of the young adult reference mean

Osteopenia (low bone mass) :BMD >1 SD below the young adult mean but <2.5 SD below this value

Osteoporosis : BMD ≥ 2.5 SD below the young adult mean

Severe osteoporosis : BMD ≥2.5 SD below the young adult mean with fragility fracture

Question 10

who should get dexa scans

Answer 10

patients over 50 with low trauma fracture

Question 11

what are the modifiable risk factors for fragility fractures

Answer 11

BMD
Alcohol
Weight
Smoking
Physical inactivity
Pharmacological risk factors

Question 12

what are the secondary causes of low bone density

Answer 12

Endocrine e.g. hyperthyroidism, hyperparathyroidism, Cushing’s disease
Gastrointestinal e.g. coeliac disease, IBD, chronic liver disease, chronic pancreatitis
Respiratory e.g. CF, COPD
Chronic kidney disease

Question 13

what is the lifestyle advice for osteoporosis

Answer 13

High intensity strength training
Low-impact weight-bearing exercise (standing, one foot always on the floor) 
Avoidance of excess alcohol
Avoidance of smoking
Fall prevention

Question 14

what are the dietary sources of calcium

Answer 14

dairy 
bread and cereals 
fish with bones 
nuts 
green veg 
beans

Question 15

what are the drug treatments for osteoporosis

Answer 15

Calcium & vitamin D supplementation
Bisphosphonates
Denosumab
Teriparatide
HRT
SERMS (Selective Estrogen Receptor Modulators)
Testosterone (hypogonadism in a younger man)

Question 16

what are bisphosphonates

Answer 16

ant resorbtive agents

Question 17

what is denosumab

Answer 17

monoclonal antibody that targets and binds with high affinity and specificity to RANKL (receptor activator of nuclear factor-kB ligand)- inhibits the development and activity of osteoclasts

Question 18

how do corticosteroids cause a decrease in bone density

Answer 18

Reduction of osteoblast activity and lifespan
Suppression of replication of osteoblast precursors

Reduction in calcium absorption

Inhibition of gonadal and adrenal steroid production

Question 19

what is pagets disease

Answer 19

abnormal osteoclastic activity followed by increased osteoblastic activity - abnormal bone structure with reduced strength and increased fracture risk

Question 20

what bones are commonly affected by pagets

Answer 20

long bones, pelvis, lumbar spine and skull (can cause hearing loss)

Question 21

how does pagets present

Answer 21

bone pain, deformity, deafness, compression neuropathies

Question 22

what cancer is a rare complication of pagets

Answer 22

osteosarcoma

Question 23

what are the findings of pagets

Answer 23

isotope bone scan
raised alk phos
normal LFTs

Question 24

what is the treatment for pagets

Answer 24

bisphosphonates if pain not responding to analgesia

Question 25

how can you FEEL if pagets is active

Answer 25

feels hot

Question 26

what is osteogenesis imperfecta

Answer 26

genetic conditions affect bone

Question 27

what mutations cause oestogenesis imperfecta

Answer 27

mutations of type 1 collagen genes (COL1A1, COL1A2)

autosomal dominant

Question 28

what signs can osteogenesis imperfecta be associated with

Answer 28

blue sclera and dentinogenesis imperfecta

Question 29

what is the treatment for osteogenesis imperfecta

Answer 29

no cure –only fracture fixation, surgery to correct deformities, bisphosphonates

Question 30

what is the T score in dexa scans

Answer 30

deviation away from young adult mean

Question 31

what is the Z score in dexa scans

Answer 31

score that is age matched

Question 32

why is vitamin D important

Answer 32

need it to absorb calcium

Question 33

what are the signs of vitamin D deficiency

Answer 33

bony pain, muscle weakness, proximal myopathy

Question 34

what hormones are found in primary hyperparathyroidism

Answer 34

high PTH
high alk phos
high bilirubin
hypercalcaemic

high calcium should suppress PTH, will have endogenous production of PTH- e.g. thyroid adenoma

Question 35

what symptoms in hyperparathyroidism

Answer 35

osteoporosis)
Kidney stones.
Excessive urination and thirst.
Abdominal pain.
Tiring easily or weakness.
Depression or forgetfulness.
Bone and joint pain.

Question 36

what cancers metastasise to bone

Answer 36

breast, bowel, bronchus (lung), renal, prostate

Question 37

what biochem would be seen in bone metastasis

Answer 37

calcium high
PTH will be low, appropriate suppression by high calcium
If PTH was high might be PTHrp being released by the tumour

Question 38

what medication to bring down calcium

Answer 38

bisphonphonates

Question 39

what is seen on x ray

Answer 39

cortico thickening, coarse trabecular patterning

Question 40

when is alk phos raised on its own

Answer 40

pagets

Question 41

high alk phos + pain =

Answer 41

pagets