Bone diseases Flashcards
Arthritis
inflammation of joints
arthrosis
non-inflammatory joint disease
arthralgia
joint pain
rheymatism and rheumatic are
not of medical use
bone
mineralised connectice tissue
3-6 month cycle
- load bearing
- dynamic - always forming and resorbing
- self repairing and able to adapt to environment
calcium, phophate and vitamin D
3 key components of bone
calcium
phosphate
vitamin D
bone turnover cycle
3-6 month cycle
osteoclasts - resorb
osteoblasts - lay matrix
bone stores what
calcium
- exchangeable Ca from bone to ECF
- Ca absorbed from gut into ECF
- Ca lost through gut and urine
Ca level in blood needs maintained at a very precise level – nerve and muscle function
- Bone and ECF work together to maintain and the PTH promote the correct location of Ca
exchangeable Ca
bone ECF
Ca absorbed
from diet (gut) into ECF
Ca lost through
urine (via gut)
Ca level in blood
needs maintained at a very precise level - needed for nerve and muscle function
bone and ECF work together to maintain and the PTH promotes the correct location of Ca
parathyroid hormone role
maintains serum calcium levels - raised if Ca level falls
- Increases calcium release from BONE
- Reduces RENAL calcium excretion
located in thyroid gland in neck
hypoparathyroidism
deficiecy of PTH
so
low serum calcium
hyperparathyroidism
2 types
- Primary
- Gland dysfunction – tumour
- High serum calcium RESULTS
- Inapp activation osteoclast
- Secondary
- low serum calcium CAUSES
Both result in increased bone reabsorption
Radiolucencies & reabsorption – areas or loss cortical surface
vitamin D action
it is needed in its biologically active form (kidneys) to absorb Ca
vitamin D level problems when (3)
- Low Sunlight Exposure
- Housebound
- Dark Skinned in Northern country – skin absorbs less vit D – often combined with cultural traditions of high clothing coverage
- Poor GI Absorption
- Poor nutrition
- Small intestinal disease - malabsorption
- Drug interactions
- Some antiepileptic drugs
- Carbamazepine, Phenytoin
- Some antiepileptic drugs
Often a combination of factors
osteomalacia
poorly mineralised osteoid matrix - normal amounts of osteoid but not mineralised
- poorly mineralised cartilage plate growth
osteoporosis
loss of mineral and matrix - correct formation but wrong amount
- so reduced bone mass
osteomalacia during bone formation called
RICKETS
related to calcium deficiency
osteomalacia after bone formation
called osteomalacia
related to calcium deficiency
osteomalacia
occurs
during bone formation - rickets
after bone formation completed
related to calcium deficiency
serum calcium preserved at expense of bone
osteomalacia investigations (2 main)
- Bone Effects
- Bones bend under pressure
- ‘bow legs’
- Vertebral compression in adults
- Bones ‘ache’ to touch – pain in nerves of lower limb
- Bones bend under pressure
- Hypocalcaemia effects
- Muscle weakness
- Trousseau & Chvostek signs positive
- Carpal muscle spasm
- Facial twitching from VII tapping
bone effects of osteomalacia
Bones bend under pressure
- ‘bow legs’
- Vertebral compression in adults
- Bones ‘ache’ to touch – pain in nerves of lower limb
hypocalcaemia effects of osteomalacia
Muscle weakness
Trousseau & Chvostek signs positive
- Carpal muscle spasm
- Facial twitching from VII tapping
appaerance of rickets
osteomalacia before bone formation complete
weak and soft bones, stunted growth, and, in severe cases, skeletal deformities.
‘bow legs’
rare now
3 management techniques of osteomalacia
- Correct the cause
- Malnutrition
- Control GI disease
- Malnutrition
- Sunlight exposure
- 30 mins x 5 weekly
- Dietary Vitamin D
osteoporosis is
- A REDUCED QUANTITY of normally mineralized Bone
An age related change - Inevitable
- Usually, many trabeculae and mineralised*
- Reduced total quantity of correctly mineralised with age
6 risk factors for osteoporosis
- AGE
- Female sex
- Endocrine
- Oestrogen & testosterone deficiency
- Cushings syndrome – inc corticosteroid levels?
- Genetic
- Family history
- Race – caucasian & asian women
- Early menopause
- Patient factors
- Inactivity
- Smoking
- Excess alcohol use
- Poor dietary calcium
- Medical Drugs use
- steroids
- antiepileptics
age and osteoporosis
- Peak Bone Mass is at age 24-35 years
Osteoporosis is found in:
- 15% women aged 50
- 30% women aged 70
- 40% women aged 80
increases with age
women have a lower peak bone mass
gender and osteoporosis
- Males have higher Peak Bone Mass
- Oestrogen withdrawal increases bone mass loss rate in women – in menopause
- Men have similar rate of decline but absolute peak bone mass is higher so takes longer to reach critical level
2 main effects of osteoporosis
Increased bone fracture risk
- Long bones – femur
- Wrists – weaker and more prone to fractire
- Vertebrae
- Height loss
- Kyphosis (bending forward of spine) & Scoliosis (shifting of lateral position of vertebrae?)
- Nerve root compression leading to back pain
Lifetime risk of hip fracture >50yrs of age
- 17.5% women
- 6% men
- After osteoporosis related hip fracture
- 20% increase in 5yr mortality
- Maximal in initial 6 months
- 20% increase in 5yr mortality
- 40% unable to walk unaided
- 60% unable to live independently
2 main ways of osteoporosis prevention
- Build maximal Peak Bone Mass
- Exercise
- High dietary calcium intake
- Higher initial point means longer to reach clinical risk level
- Reduce rate of Bone Mass loss
- Continue exercise and calcium intake
- Reduce hormone related effects
- Oestrogen Hormone replacement therapy
- MOST effective if early menopause
- Reduce drug related effects
- Consider ‘Osteoporosis Prevention’ drugs
- BISPHOSPHONATES – indicated by strong family history
how to build maximal peak bone mass
so preventing osteoporosis
- Exercise
- High dietary calcium intake
Higher initial point means longer to reach clinical risk level
how to reduce rate of bone mass loss
so preventing osteoporosis
- Continue exercise and calcium intake
- Reduce hormone related effects
- Oestrogen Hormone replacement therapy
- MOST effective if early menopause
- Reduce drug related effects
- Consider ‘Osteoporosis Prevention’ drugs
- BISPHOSPHONATES – indicated by strong family history
Hormone replacement therapy
- oestrogen only
- Reduces osteoporosis risk
- Increases breast cancer risk
- Increase endometrial cancer risk
- Patients who have NOT had a hysterectory
- Combine with a progestogen to reduce risk
- Patients who have NOT had a hysterectory
- May reduce ovarian cancer risk
- Increases DVT risk
Benefit lost after HRT stops!
- 5yrs post treatment BMD ‘normal’
biphosphonates
reduce osteoclasts action (poison and reduce numbers) so less bone removed means less bone mass lost
Non-Nitrogenous
- Etidronate (1)
- Clodronate (10)
- Tildronate (10)
Nitrogenous
- Pamidronate (100)
- Neridronate (100)
- Olpadronate (500)
- Alendronate (500)
- Ibandronate (1000)
- Risedronate (2000)
- Zoledronate (10000
biphophonates effectiveness
Alendronate or Risedronate in an osteoporosis risk population
- Reduce vertebral fracture risk by 50%
- Reduce other fractures by 30-50%
- benefit lost if drug discontinued
- Can be combined with HRT
extraction of teeth complication
- Benefits and risks in SDCEP
