Bone, bone disorders and arthritis Flashcards
What does connective tissue consist of?
Cells, fibres and gel-like substance
what is a matrix?
material in between the cells
What are the organic components of bone?
cells - osteoblasts, osteocytes and osteoid
what is the function of bone?
provide support, structure and protect organs
mineral storage, fat storage, hormone production and blood cell formation (which occurs in the blood marrow)
Typically, what are the open spaces of bone filled with?
Bone marrow
Where are osteogenic cells found?
In the periosteum and endosteum
HiWhy is bone remodelling so important?
bone is constantly exposed to insults and also for regulation of metabolic processes (for release or absorption of ions)
What is the origin of osteoclasts?
WBC lineage (mostly monocytes and macrophages)
Which chemical messengers are associated with bone resorption (eg: when calcium levels are low)
PTH, vitatmin D
Which chemical messengers are associated with bone formation? (eg: when calcium levels are high)
Oestrogen / calcitonin
Is inflammation associated with bone resorption or bone formation?
Bone resorption
What happens to the bone if there is a deficiency of vitamin D?
failure of osteoid to mineralise (kicks off transcription genes which cause mineralisation of newly secreted bone)
(low levels of vitamin D encourage bone resorption to increase amount of free calcium)
What is the cause of primary hyperparathyroidism?
adenoma of one of the parathyroid glands
What does hyperparathyroidism do to levels of PTH and bone?
High PTH levels trigger the bones to release more calcium than normal into the blood. The loss of calcium from the bones may weaken them
What is the cause of secondary hyperparathyroidism?
chronic renal disease
you get calcinuria (calcium salts in urine)
so to compensate this PTH»_space;
What is a brown tumour or giant cell granuloma?
A mass formed where a bone lesion arises in an area of high osteoclast activity
In the early inflammatory stage of bone healing, what is formed at the fracture site? Why is the formation of this so important?
Haematoma - it supplies the stem/growth cells required for healing
What does the granulation tissue turn into in the repair stage of bone healing?
Callus
What is the process called that turns primary callus into secondary callus? (soft callus - cartilage –> hard callus - woven bone)
endochondral ossification
What can happen if the fracture site is not adequately immobilised?
A fibrous union may form in place of solid bone formation (there will be degree of permanent mobility)
What factors can impact fracture healing?
blood supply to the fracture site
infections
underlying bone pathologies
whether fracture is closed/compounbd
co-morbid conditions (DB, use of long term corticosteroids, previous radiotherapy at site)
use of cox-2-inhibitors
What are some of the clinical presenations of osteogenesis imperfect “brittle bone disease”?
blue sclera
deafness
> risk of fracture
shortened appearance
class 3 skeletal
What is osteopetrosis?
decreased osteoclastic activity (osteoclasts fail to resorb bone)
Why is the bone brittle in osteogenesis imperfecta?
lack of organic component (collagen)
What T-score would indicate osteoporosis?
-2.5 or less
Why is osteoporosis a normal part of the aging process?
Bone density declines as we get older (as oestrogen is in short supply in post-menopausal and androgen levels fall in men)
What medication can be given to patients with osteoporosis to prevent bone loss?
Vitamin D/calcium
BISPHOSPHONATES
What medication can be given to patients with osteoporosis to prevent bone loss?
- Vitamin D/calcium
- BISPHOSPHONATES
- alendronic acid, ibandronic acid, risedronate, zolendronic acid)
- SERMs (selective estrogen receptor modulator) eg: raloxifene (similar action as endogenous ostrogen)
- HRT - but primarily for symptoms of menopause
How is osteoporosis managed?
- Education
- Physiotherapy
- Physical aids
- Active fall prevention
- Surgery
What is Paget’s disease?
Disorder of bone turnover/remodelling
What treatments can be used in Paget’s?
BISPHOSPHONATES!
what implications can bisphosphonates cause in dental tx?
BRONJ - impairs bony healing
What is osteoarthritis?
progressive erosion (degeneration) of articular cartilage
Over time, what can happen to the bone in osteoarthritis?
it becomes exposed and damaged leading to cysts and abnormal growth (osteophytes) –> inflammation
What joints are typically affected in osteoarthritis?
Weight-bearing joints (hips/knees)
What are some of the signs of osteoarthritis?
Signs: crepitus, restricted movement, bony enlargement
What are some of the symptoms of osteoarthritis
pain and functional limitation
What is the most characteristic feature of osteoarthritis ?
Narrowing joint space
What type of nodes are commonly seen in long term osteoarthritis?
Heberden’s nodes
How is osteoarthritis managed?
Education
Weight loss
Physiotherapy
Analgesia (topical NSAIDs_
Intra articular corticosteroid for single painful joints
Intramuscular corticosteroid for widespread arthritis
Surgery
What is rheumatoid arthritis?
Multi-system inflammatory condition - autoimmune condition
Does RA typically affect younger or older patients?
Younger pts
What are the signs you will typically see in RA? (signs of inflammation)
calor, dalor, rubor, tumor, functio laesi
- heat, pain, redness, swelling, loss of function
Which feature is highly indicative of RA?
early morning stiffness
What is ankylosing spondylitis? Is it more common in male or female? Is there a genetic predisposition?
chronic inflammatory arthritis, more common in male, genetic predisposition for those with certain tissue types (HLA-B27) - you may see families where father and son are affected
What considerations should be given for patients with ankylosing spondylitis?
- Require neck support / pillows
- Shorter appts
- May have profound immunosuppression due to long-term corticosteroid use
What area of the body is more affected in patients with ankylosing spondylitis?
The spine
