1 - Bone disease Flashcards
Define arthritis.
Inflammation of joints
Define arthrosis.
Non-inflammatory joint disease
Define arthralgia.
Joint pain
Describe bone.
- mineralised connective tissue
- load bearing
- dynamic (constantly remodelling and self repairing)
- requires calcium, phosphate and vit D to repair
How do bone and calcium interact?
- if systemic calcium is low, bone will resorb to release calcium into blood
- caused by an increase in parathyroid hormone
Describe PTH and its relationship to calcium.
- maintains serum calcium levels
- increased secretion of PTH if calcium low
- increases calcium release from bone
- decreases renal calcium excretion
What is primary hyperparathyroidism and what is its effect?
- gland dysfunction (often caused by a tumour)
- increased secretion of PTH
- inappropriate activation of osteoclasts
- increased bone resorption
What is secondary hyperparathyroidism and what is its effect?
- low serum calcium triggers
- increased secretion of PTH
- appropriate activation of osteoclasts
- regulates serum calcium
What are causes of low vit D?
- low sunlight exposure (housebound or dark skinned in a northern country)
- poor GI absorption
- drug interactions (anti-epileptics)
Define osteomalacia.
- normal amount of formation of bone
- poorly mineralised osteoid matrix and cartilage plate
- bone is pliable and soft
Define osteoporosis.
- mineralisation and matrix formation are correct but there is reduced quantity
- reduced bone mass
What is rickets?
Osetomalacia that occurs during bone formation
How does osteomalacia affect the bone?
- legs bow (children)
- vertebral compression (adults)
- bones ache to touch
What are the symptoms of hypocalcaemia?
- muscle weakness
- carpal muscle spasm
- facial twitching when VII tapped
How does osteomalacia present in blood tests?
- decreased serum calcium
- decreased serum phosphate
- alkaline phosphatase very high (bone turnover)
- plasma creatine increased (if renal cause)
- plasma PTH increased (if 2y hyperparathyroidism)
How do you manage osteomalacia?
- correct malnutrition (address if GI cause)
- sunlight exposure 5x30mins weekly
- vit D supplement
What are the risk factors for osteoporosis?
- age
- F > M
- endocrine (oestrogen/testosterone deficiency, Cushings syndrome)
- genetic (FH, race, early menopause)
- patient factors (inactive, smoking, alcohol, poor diet)
- drugs (anti-epileptic, steroids)
At what age is peak bone mass?
24-35 years
Why is osteoporosis more common in women?
- males have higher peak bone mass than women
- oestrogen withdrawal (menopause) increase bone mass loss rate
What are the effects of osteoporosis?
- long bone fracture (femurs, wrists, hip fracture)
- height loss
- kyphosis (bending forward)
- scoliosis (lateral shifting of vertebrae)
- nerve root compression (back pain)
How can you prevent osteoporosis?
- build maximal peak bone mass (high calcium diet, exercise)
- reduce rate of bone mass loss (continue with exercise and calcium in diet, HRT, bisphosphonates)
Describe HRT in relation to osteoporosis.
- most effective during early menopause
- loses effect 5 years after stopping
- increased breast, endometrium, ovarian cancer risk
- increased DVT risk
What are bisphosphonates?
- drugs that act to reduced osteoclast activity by poisoning them
- reduced osteoclasts = reduced bone loss
What bisphospohonates are commonly used?
- alendronate
- ibandronate
- zoledroante (most potent, given once a year)
