Non-neoplastic Bone Flashcards
What is the main function of osteoblasts?
Bulit + lay down of Bone
Osteo B lasts B uilt bone
What is the main function of osteoclasts?
Resorb bone
Multinucleate cells of macrophage family
In What categories can metabolic bone disease be classified (different aetiologies) ?
- non-endocrine (e..g age-related osteoporosis)
- Related to endocrine abnormality
- Disuse osteopenia
What is the usual aetiology of osteoporosis?
Age related (post-menopausal/ age)
or secondary to systemc diseases/ drugs (steroids!)
What is the pathophysgioloy of osteoporosis?
What test would you do and what do you expect?
Different processes leading to
↓bone mass
DEXA scan: T score > 2.5 SD below normal (1-2.5 = osteopaenia)
What are the typical clinicla features of osteoporosis?
Low impact fractures (#)
(hip - NOF, vertebrae; wrists - Colles’)
Pain (back) (vertebra # +/- nerve pain)
What are the expected x-ray changes in a patient with osteoporosis?
None
What does histology of osteoporosis show?
Loss of calcellous bone
What is osteomalacia/ rickets? (pathophysiology)
Overall calcium deficiency leading to
Reduced bone mineralisation
What are characteristic features of osteopenia on X-ray?
Looser’s zones
(pseudo-fractures)
Splaying of metaphysis
What are histological features of osteomalcia and rickets?
Excess of unmineralized bone (osteoids)
What are the biochemical findings of Osteomalacia/ Rickets?
Normal/ Low calcium
Low Po4
High ALP
Explanation:
Overall calcium is low –> activation of osteoclasts and increased bone resobtion to even out low calcium (can be corrected to normal biochemical levels and explains the high ALP due to high bone turnover)
Phosphate is low due to incereased renal excretion of phosphate due to higher PTH levels
What are the causes of primary hyperparathyroidism?
Parathyroid adenoma
Parathyroid hyperplasia
carcinoma
MEN
What are the symptoms of primary hyperparathyroidism?
Symptoms of Hypercalcaemia
Moans (abdominal pain), constipation
Stones: renal stones
Bone pains + fractures
Groans: psychological changes (depression, confusion)
What are common x-ray changes of Primary hyperparathyroidism?
Brown’s tumours
(collection of multinucleate giant cells)
Salt and pepper skull
Subperiosteal bone resorption in phalanges
Brow’s tumour
What is osteitis fibrosa cystica?
A rare skeletal disorder seen in advanced hyperparathyroidism characterized by replacement of calcified bone with fibrous tissue
(Most often seen in primary Hyperparathyroidism)
What are the biochemical findings in primary hyperparathyroidism?
High calcium
Low/Normal P04
High/normal ALP
High/ normal PTH (inappripriartely normal)
What are the disease features of Paget’s disease of the bone?
Idiopathig high bone turnover
Seeing initally increased lysis (lytic lesions), then mixed (lytic + sclerotic) and sclerosis (sclorotic lesions)
What are the symptoms of Paget’s disease?
Bone pain
Microfractures
Nerve compression (due to expansion of bone: sensorineural hearing loss, sciatica)
infreased head size
high output cardiac failure
Whatare histological findings of Paget’s disease of the bone?
Huge osteoclasts
w > 100 nuclei Mosaic pattern of lamellar bone (like jigsaw puzzle)
What are the biochemical findings of Paget’s disease of the bone?
Normal Calcium, Normal phosphate
High ALP
What are the 4 stages of bone repair (after #)?
- Organisation of haematoma (pro-callus)
- Formation of fibrocartilaginous callous
- Mineralisation of fibrocartilaginous callous
- remodeling of bone among weight bearing lines
What are the most common site of infection for osteomyelitis?
Vertebrae
Jaw (dental abscess)
toe (diabetic ulcers)
Long bones
Whatare the expected X-ray changes in osteomyelitis?
Early: sub-periostel new bone formaion
Later (10 days) lytic destruction of bone
