pathophysiology

Question 1

6 reasons to perform a bone biopsy

Answer 1

confirm diagnosis of bone disorder, find cause of/evaluate ongoing bone pain and tenderness, investigate abnormality seen on x-ray, diagnose bone tumour (benign vs malignant), determine cause of unexplained infection, evaluate therapy performance

Question 2

2 types of bone biopsy

Answer 2

closed, open

Question 3

what equipment is used for a closed biopsy

Answer 3

Jamshidi needle, which returns with a core of bone

Question 4

when are open biopsies done

Answer 4

for sclerotic/inaccessible lesions e.g. osteoporosis, or if require larger bone sample

Question 5

if non-specific location of bone biopsy required, what is this location and why

Answer 5

transilliac bone biopsy, as can see all types of bone in small region (e.g. vs femur head, where may only see articular cartilage, trabecular bone, cortical bone)

Question 6

3 histological stains

Answer 6

H and E on decalsified samples, Masson-Goldner Trichrome (mineralised vs non-mineralised), Tetracycline/Calcein labelling (rate of bone turnover)

Question 7

H and E staining shaft of long bone

Answer 7

see periosteum, cortical bone (and osteocytes), marrow cavity

Question 8

H and E staining articular surface

Answer 8

stains cartilage and trabecular bone

Question 9

H and E staining bone cells

Answer 9

identify osteoclasts, osteoblasts and osteocytes

Question 10

Masson-Goldner Trichrome staining

Answer 10

unmineralised bone stains orange, mineralised bone stains green (useful in osteomalacia)

Question 11

Tetracycline/Calcein labelling use

Answer 11

i.v. injection, incorporated into osteoid being mineralised, producing fluorescent line; inject again 2 days later, so can measure amount of mineral laid down over that time by measuring distance between 2 lines (mineral apposition rate) and proportion of bone covered (turnover rate)

Question 12

risk of biopsy

Answer 12

low, but risk of infection or fracture