Metabolic Bone Disease - Histopathology Flashcards
The functions of bone
STRUCTURE – give structure and shape to the body • MECHANICAL – sites for muscle attachment • PROTECTIVE – vital organs and bone marrow • METABOLIC – reserve of calcium and other minerals
What are the five types of anatomical bones
Flat,long,short/cuboid - stabilisation ,irregular - protection of organs ,sesamoid- protective function
What are the two types of macroscopic bones
trabecular/cancellous/spongy
– cortical/compact
Cortical bone microanatomy
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What is the immature woven bone?
Disorganised, do not have structure, in developing skeleton, in situations with rapid bone and high bone turnover, very weak
What are the key bone cells?
Osteoclasts
Osteoblasts
Osteocytes
What are osteocytes?
Mechanosensory network embedded in mature bone
What are osteoclasts?q
Multi nuclear cells that resorb/remove bone
What are osteoblasts
Produce osteoid to form new bones
What is the bone remodelling cycle
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When does bone disease occur?
When there is excesss removal of bone by osteoclasts or excess increase in bone by osteoblasts.
Why perform a bone biopsy?
Confirm the diagnosis of a bone disorder
• Find the cause of or evaluate ongoing bone pain or
tenderness
• Investigate an abnormality seen on X-ray
• For bone tumour diagnosis (benign vs malignant)
• To determine the cause of an unexplained infection
• To evaluate therapy performance
What are the two types of bone biopsy?
Closed - needle - core biopsy (jamshidi needle)
Open - for sclerotic or inaccessible lesions
Transilliac bone biopsy
Typical location for bone biopsy bcs you can see all the different types of bone
What are some histological stains
- H&E
- Masson - Goldner Trichrome
- Tetracycline/Calcein labelling
How does the stains work
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What is metabolic bone disease
A group of diseases that cause reduced bone mass and bone strength
DUE to the imbalance of various chemicals in the body (eg: vitamins, minerals, hormones etrc(
That CAUSE altered bone cell activity, rate of mineralisation , or changes i bone structure
What is osteoporosis
Defined as bone mineral density T-score of -2.5 or lower SD different from mean peak bone mass BMD
What is primary osteoporosis
No external cause of disease, caused by age or post-menopause
What is secondary osteoporosis?
Caused by drugs or systemic disease
Two types of ostewoporosis
High turnover and low turnover
Which type of bone does osteoporosis affect more
Trabecular bone bcs its more metabolically active
What are the histopatholigical features of osteoporosis
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What is osteomalacia
Defective mineralisation of normally synthesized bone matrix
What is osteomalacia in children called
Ricxkets
What are the two types of osteomalacia
– Deficiency of vitamin D – Deficiency of PO4
Describe the vitamin D - calcium axis
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What are the histopathological features of osteomalacia
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What are looser;s zone fractures
Pseudofractures in high tensile stress areas + (describe more)
What is the sequelae of events in osteomalacia
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What is renal osteodystrophy
Comprises all the skeletal changes resulting from chronic renal disease:-
– Increased bone resorption (osteitis fibrosa cystica) – Osteomalacia
– Osteosclerosis
– Growth retardation
– Osteoporosis
What is Paget’s disease?
Disorder of bone turnover
