Biochemistry

Question 1

define osteoporosis

Answer 1

defect of bone characterised by reduced bone mineral density and increased porosity (the bone is of normal quality, there is just not enough of it)

Question 2

what does osteoporosis lead to?

Answer 2

fragility of bone and increased fracture risk (occurring after little or no trauma)

Question 3

when does loss of mineral density of bone happen?

Answer 3

around 30 years of age with slow down in osteoblastic activity

Question 4

when do females lose more bone density?

Answer 4

after menopause due to increased osteoclastic bone resorption with loss of protective effects of oestrogen

Question 5

two types of primary osteoporosis

Answer 5

1. type 1= post menopausal osteoporosis with exacerbated loss of bone in the post-menopausal period
2. type 2= old age with greater decline in bone mineral density than expected

Question 6

risk factors for post-menopausal osteoporosis

Answer 6

white caucasian
familial
smoking
alcohol abuse
lack of exercise
poor diet

Question 7

what fractures are common in post-menopausal osteoporosis

Answer 7

colles fracture

vertebral insufficiency fractures

Question 8

risk factors for old age osteoporosis

Answer 8

chronic disease
inactivity
reduced sunlight exposure (vitamin D)

Question 9

what fractures are common in old age osteoporosis

Answer 9

vertebral fractures

femoral neck fractures

Question 10

what can osteoporosis occur secondary due to?

Answer 10

corticosteroid use
alcohol abuse
malnutrition
chronic disease
endocrine disorders

Question 11

diagnosis of osteoporosis

Answer 11

DEXA scan (measure bone mineral density)
- serum calcium and phosphate normal

Question 12

management of osteoporosis

Answer 12

exercise, diet and sunlight
calcium and vitamin D supplements
desunomab (monoclonal antibody which reduces osteoclast activity)
strontium
zoledronic acid (once yearly)

Question 13

define osteomalacia (Rickets in children)

Answer 13

abnormal softening of bone due to deficient mineralisation of osteoid secondary to inadequate amounts of calcium and phosphorus

Question 14

cause of osteomalacia

Answer 14

insufficient calcium absorption from the intestine because of lack in diet or resistance to the action of vitamin D or phosphate deficiency caused by increased renal losses

Question 15

specific causes of osteomalacia

Answer 15

malnutrition
malabsorption
lack of sunlight exposure
hypophosphatemia 
long-term anticonvulsant use
chronic kidney disease

Question 16

presentation of osteomalacia

Answer 16

bone pain
deformities
pathological fractures

Question 17

diagnosis of osteomalacia

Answer 17

radiographs

low calcium, low phosphate and high serum ALP

Question 18

management of osteomalacia

Answer 18

vitamin D therapy with calcium and phosphate supplementation

Question 19

define hyperparathyroidism

Answer 19

overactivity of the parathyroid glands with high levels of PTH

Question 20

causes of primary hyperparathyroidism

Answer 20

benign adenoma
hyperplasia
sometimes malignancy

Question 21

what does overproduction of PTH cause?

Answer 21

results in hypercalcaemia which causes fatigue, depression, bone pain, myalgia, nausea, thirst, etc.

Question 22

diagnosis of hyperparathyroidism

Answer 22

serum PTH and elevated Ca

phosphate is normal or low

Question 23

secondary hyperparathyroidism

Answer 23

physiological overproduction of PTH secondary to hypocalcaemia