Biochemistry

Question 1

What is osteoporosis

Answer 1

Quantitative defect of bone, reduced bone mineral density, increasing porosity, fragility

Question 2

Define osteopenia and osteoporosis

Answer 2

Osteopenia: 1 - 2.5 SD
Osteoporosis: greater than -2.5SD

Question 3

Type 1 osteporosis

Answer 3

Post-menopausal
Smoking, alcohol, poor diet, lack of exercise
Fractures (colles and vert insuff)

Question 4

Type 2 osteoporosis

Answer 4

Old age
Chronic disease, low vit D, in activity
Fractures (femoral neck, vert)

Question 5

Serum Ca and phosphate in osteoporosis

Answer 5

Normal

Question 6

Treatment of osteoporosis

Answer 6

Exercise before 30, diet, sun
Ca and vit D
Bisphosphonates (alendronate, risedronate)
MAB (desunomab)
Strontium
HRT

Question 7

What do bisphosphonates do?

Answer 7

Decrease Oc resorption

Question 8

What does strontium do?

Answer 8

Increases Obs

Reduces Ocs

Question 9

What does denusomab do?

Answer 9

Reduces Oc activity

Question 10

What is osteomalacia?

Answer 10

Qualitative defect of bone, abnormal softening due to deficient mineralisation of osteoid secondary to inadequate Ca and phosphate

Question 11

Cause of osteomalacia

Answer 11

Insufficient absorption of Ca from intestine
Lack of dietary Ca
Resistance or lack of Vit D
Phosphate defiicency (renal losses, tubular acidosis, alcohol)

Question 12

Symptosm of osteomalacia

Answer 12

Bone pain
Deformities
Pathological fractures
Hypocalcaemia = paraesthesia, cramps, irritability, brittle nails, pseudofractures

Question 13

Bone biochem in osteomalacia

Answer 13

Low Ca and phosphate

High ALP

Question 14

Treatment of osteomalacia

Answer 14

Vit D therapy

Ca and phosphate

Question 15

Hyperparathyroidism

Answer 15

Overactivty of PT glands = high Ca

Fragility fractures, lytic lesions (Brown tumours)

Question 16

Primary hyperparathyroidism

Answer 16

Benign adenoma, hyperplasia
Hypercalcaemia = stones, bones, moans, groans
High PTH, high Ca, normal/low phosphate

Question 17

Secondary hyperparathyroidism

Answer 17

Overproduction of PTH due to hypocalcaemia

Caused by CKD or vit D deficiency

Question 18

Tertiary hyperparathyroidism

Answer 18

Chronic secondary hyperparathyroidism long standing (CKD) = adenoma = produces PTH even if Ca corrected

Question 19

Treatment of hyperparathyroidism

Answer 19

Skeletal stabilisation
Remove PT glands
Vit D supplements
IV fluids, bisphosphonate, calcitonin

Question 20

Renal dystrophy

Answer 20

Bone changes in response to CKD
Reduced phosphate excretion and inactive Vit D = secondary hyperparathyroidism = osteomalacia, sclerosis and calcification of soft tissue

Question 21

Paget’s disease

Answer 21

Chronic disorder resulting in thick, brittle, misshapen bones
Increased Ocs = increased turnover
Obs = correct resorption
Pelvis, femur, skull, tibia, ear ossicles = deafness

Question 22

Symptoms of Paget’s

Answer 22

Arthritis
Pathologic fractures
Deformities
Pain
HF
Raised ALP, Ca and phosphate normal

Question 23

Treatment of Paget’s

Answer 23

Bisphosphonates (inhibit Ocs)
Calcitonin (if lytic)
Joint replacement