Bone Diseases Flashcards
1
Q
What is arthritis?
A
inflammation of joints
2
Q
What is arthrosis?
A
non-inflammatory joint disease
3
Q
what is arthralgia?
A
joint pain
4
Q
What is bone and what are its characteristics?
A
mineralised connective tissue
- load bearing
- self repairing
- dynamic
- adaptable, constantly changing
5
Q
How long does bone formation take and what are the key components?
A
3-6 months
- calcium
- phosphate
- vitamin D
6
Q
Describe the movement of calcium in and out of bone
A
- calcium store in bone
- some exchangeable calcium
- exchangeable calcium moves from bone to ECF
- calcium absorbed from gut into ECF
- calcium lost through gut and urine
- calcium level in blood precisely maintained
- vital for nerve and muscle function
- bone, ECF and parathyroid hormone
- low dietary calcium causes plasma calcium to fall
- parathyroid hormone increases active Vit D production
- calcium loss from kidneys reduced
- bone loss promoted
- calcium absorbed into ECF to restore plasma level
7
Q
What is the role of parathyroid hormone in relation to bone?
A
- maintains serum calcium level
- hormone level raised if calcium levels fall
- increases calcium release from bone
- reduced renal calcium excretion
8
Q
What is hyperparathyroidism and how does it affect bone?
A
- increased parathyroid hormone levels
- results in inappropriate activation of osteoclasts
- increased bone resorption
- radiolucencies apparent on radiographs
- primary
- gland dysfunction (tumour)
- high serum calcium
- secondary
- low serum calcium
9
Q
How is vitamin D produced by the body
A
- sunlight
- produced by cholecalciferol in the skin
- processed by liver to create active form
- 1,25-dihydroxycholecalciferol
- dietary
- orange juice, milk, fish
- processed by liver and kidney to create active form
9
Q
How is vitamin D produced by the body
A
- sunlight
- produced by cholecalciferol in the skin
- processed by liver to create active form
- 1,25-dihydroxycholecalciferol
- dietary
- orange juice, milk, fish
- processed by liver and kidney to create active form
10
Q
What factors can result in low vitamin D?
A
- low sunlight exposure
- housebound
- dark skin (pigment less efficient at absorption)
- cultural clothing
- poor gastrointestinal absorption
- poor nutrition
- small intestine disease (malabsorption)
- drug interactions
- some anti epileptic drugs
- carbamazepine, phenytoin
- usually a combination of the above factors
11
Q
What is osteomalacia?
A
- bone formed normally but not fully calcified resulting in inadequate remineralisation
- poorly mineralised osteoid matrix
- poorly mineralised cartilage growth plate
- bone is soft and pliable, compress under pressure
- bones ache to touch
- due to calcium deficiency
- serum calcium preserved at expense of bone
- called rickets if during bone formation
- bones bend under pressure
- rarely seen now as a result of deficiency
- more common as a result of vitamin D resistance
- called osteomalacia if after bone formation
- vertebral compression
- nerve pain in lower limbs
12
Q
What is osteoporosis?
A
- bony matrix and mineralisation are correct but reduced bone mass
- loss of mineral and matrix
- inevitable, age related change
- increased fracture risk
- bones cannot withstand stresses applied
- especially long bones
- wrists are high risk
- hip fracture (increased mortality)
- vertebrae affected
- height loss
- kyphosis (forward bending, vertebral bodies collapse)
- scoliosis (lateral tipping)
- nerve root compression (back pain)
13
Q
What are the effects of hypocalcaemia?
A
- muscle weakness
- Trousseau sign (carpal muscle spasm)
- Chvostek sign (facial twitching from CNVII tapping)
14
Q
What would serology show in an osteomalacia patient?
A
- decreased serum calcium
- decreased serum phosphate
- very high alkaline phosphatase
- measure of bone turnover
- high when problem with calcium levels
- plasma creatinine
- increased if renal cause
- plasma parathyroid hormone
- increased if secondary hyperparathyroidism
15
Q
How is osteomalacia managed?
A
- correction of the cause
- restore calcium to diet
- control GI disease
- increase sunlight exposure
- 30 minutes, 5 times weekly
- dietary vitamin D
16
Q
What are the risk factors for osteoporosis?
A
- age
- gender
- higher in female
- endocrine
- oestrogen and testosterone deficiency
- Cushing’s syndrome (increased blood corticosteroid)
- genetic
- family history
- race (caucasian, asian)
- early menopause
- patient factors
- inactivity
- smoking
- excessive alcohol use
- poor dietary calcium
- medical drug use
- drugs affecting calcium metabolism
- steroids
- anti epileptics
17
Q
At what age range does peak bone mass occur and why does this relate to a higher incidence of osteoporosis in women?
A
- peak bone mass at 24-35 years
- males have higher average peak bone mass
- more bone to lose before reaching osteoporosis
- females have a rapid decrease in bone mass
- oestrogen withdrawal increased bone mass loss rate
- likely more similar due to modern day female lifestyles reducing risk factors
18
Q
At what age range does peak bone mass occur and why does this relate to a higher incidence of osteoporosis in women?
A
- peak bone mass at 24-35 years
- males have higher average peak bone mass
- more bone to lose before reaching osteoporosis
- females have a rapid decrease in bone mass
- oestrogen withdrawal increased bone mass loss rate
- likely more similar due to modern day female lifestyles reducing risk factors
19
Q
How can osteoporosis be prevented?
A
- build maximal peak bone loss
- exercise
- high dietary calcium intake
- ensure adequate vitamin D levels
- reduce rate of bone mass loss
- continue exercise and calcium intake
- reduce hormone related effects (HRT, especially early menopause)
- reduce drug related effects
- consider osteoporosis prevention drugs
- useful in case of family history or early detection
- bisphosphonates
20
Q
What is hormone replacement therapy?
A
replacement of hormones that are deficient in the body
- oestrogen only
- reduces osteoporosis risk
- increases break cancer risk
- increased endometrial cancer risk (progesterone reduces)
- may reduce ovarian cancer risk
- increased DVT risk
- benefit of HRT stops when
- 5 years post treatment bone loss is normal
21
Q
How do bisphosphonates work and what are the most commonly prescribes types?
A
- prevent osteoclastic activity by poisoning osteoclasts and reducing their numbers
- less bone removed so bone mass preserved
- reduce fracture risk
- benefit lost if drug discontinued
- can combined with HRT
- risk of MRONJ with dental extractions
- alendronate
- ibandronate
- zoledronate
- given once a year
