Histopath - metabolic bone disease Flashcards
2 main types of bone in the body? Where are these bones?
Cortical aka compact = long bones
Trabecular aka cancellous = vertebrae + pelvis
RANK is expressed by which cell? if RANK levels are high, what does this mean for rate of bone resorption?
RANK = expressed by osteoclast precursors.
Upon interaction with RANKL –> osteoclast precursors differentiate
Thus, high RANK –> increased bone resorption :(
OPG is expressed by which cell? How does high OPG levels affect bone resorption activity?
OPG = expressed by osteoblasts
- High OPG –> reduced bone resorption
Main difference in structure between lamellar and woven bone?
Lamellar bone has organised collagen arranged in alternating orientations
Woven bone has disorganised collagen fibres, seen in Paget’s disease + tumours
Where is bone biopsy taken from, in suspected metabolic bone disease?
Iliac crest
Features of renal osteodystrophy? Name 4
- Osteomalacia (due to low calcitriol synthesis)
- 2ndary hyperPTH (due to low Vit D)
- Osteitis Fibrosis Cystica = bone changes from high PTH (salt + pepper full, brown tumours)
- Osteoporosis (poor bone mineralisation)
Renal osteodystrophy - levels of Ca? PO4? PTH?
Ca low
PO4 - high
PTH high
Paget’s disease - 3 phases?
Osteolytic
Mixed osteolytic osteosclerotic
Quiescent osteosclerotic
Paget’s disease - key serum measurement?
V high ALP.
No change in Ca and PO4 levels
3 causes of primary hyperPTH?
Parathyroid adenoma, Hyperplacia/carcinoma, MEN
Symptoms (in temporal order) in Osteomalacia?
Bone pain –> proximal muscle weakness –> deformity
Describe what osteitis fibrosis cystica is?
Osteoclastic bone resorption –> replacement with fibrous tissue
Bone changes consistent with osteitis fibrosis cystica?
Brown’s tissue
Salt and pepper skull
2 X-ray features of osteomalacia
Looser’s zones (pseudo fractures)
Splayed metaphyses
