Bone disease Flashcards
What is osteoporosis?
a condition of skeletal fragility characterised by reduced bone mass and micro architectural deterioration predisposing to an increased risk of fractures
bone density >2.5 standard deviations below the young adult mean
What are the secondary causes of osteoporosis?
drugs - steroid, sex hormone antagonist, lithium
endocrine - cushings, acromegaly, hypopituitarism
inflammatory - RA, AS, IBD
Nutritional - Vitamin D, calcium malabsorption
Genetic - marfan’s, turners
What are the main RFs for developing osteoporosis?
old age (particularly post-menopausal women) disuse perimenopausal state (HRT use minimises this) prolonged corticosteroid therapy (RA) endocrine disorders liver disease (alcoholic liver disease)
Describe the pathology of osteoporosis?
bone remodelling involves resorption by osteoclasts and replacement by osteoblasts. This is normally in equilibrium. Osteoporosis when this process is unbalanced resulting in the loss of bone mineral density
What is the clinical presentation of osteoporosis?
fracture is the only cause of symptoms - asymptomatic until fracture
How does a vertebral crush fracture present?
sudden onset of severe pain in the spine
localised at the affected level and radiating around to the front
only 1/3 vertebral fracture is symptomatic
increasing kyphosis, height loss and abdominal protuberance followed by a crushed vertebra
Which fractures are very suggestive of osteoporosis?
vertebrae
hip
wrist
What investigations should be used to investigate osteoporosis?
X-ray
DEXA bone scan
Biopsy can be used if diagnosis is in doubt
other tests: renal function bone profile (calcium, vitamin D, phosphate, alkaline phosphate, PTH) thyroid function test bone turnover markers multiple myeloma screen
What are the signs of osteoporosis on x-ray?
multiple fractures
looser zones
pencil thin cortices
increased alkaline phosphatase
What is the gold standard test for osteoporosis?
DEXA scan
What are lifestyle advice can be given to patients with osteoporosis?
improve calcium intake
weight bearing exercise
smoking cessation
What medical management is used in osteoporosis?
- vitamin D and calcium supplements
- bisphosphonates
- denosamab S/C ever 6/12 (monoclonal antibody)
Other: HRT, testosterone treatment, parathyroid hormone
What is the definition of osteomalacia?
normal deposition of bone osteoid by osteoblasts and normal bone architecture with inadequate mineralization of bone matrix
Which bisphosphonates are used to treat osteoporosis?
allerdronic acid - 70mg weekly
risedronate sodium
zolendronic acid IV
What prevention and lifestyle advice is given to women at risk of developing osteoporosis?
oestrogen hormone replacement therapy is the most effective way of maintaining bone density and reducing fracture risk.
don’t use is risk of breast cancer
continue for no longer than 5 years
What are the causes of osteomalacia?
usually as a result of abnormalities in vitamin D metabolism
- inadequate intake
- inadequate body synthesis of vitamin D
- malabsorption due to intestinal disease
- renal disease
- rare: liver diseas, drug therapy
How does osteomalacia present in adults?
- vague bone or muscle pain with tenderness usually in the lower limbs
- pathological fractures/microfractures of the lower limb
- generalised weakness
How does osteomalacia present in children (=rickets) ?
- neonatal rickets may present with a thin deformed skull
- thickening of the wrists
- bow legs
- coxa vera
- tetany and convulsions are seen occasionally
What investigations should be used when suspecting osteopenia?
Bloods: serum ALP, plasma calcium, serum phosphat, serum-25-hydroxyvitamin D
X-ray
Iliac crest biopsy (used if tests don’t confirm diagnosis)
Tetracycline-labelled bone biopsy (used in research)
What is the difference between osteoporosis and osteomalacia?
osteoporosis = decreased bone mass and normal ratio of mineral to matrix osteomalacia = ratio of mineral to matrix is decreased
What is Pagets disease of the bone?
common disease of unknown cause affecting the bone in the elderly
chronic disorder that typically results in enlarged deformed bones due to excessive breakdown and formation of bone tissue that causes bones to weaken resulting in bone pain, arthritis, deformities or fractures
Describe the pathology of Paget’s disease
abnormally large multinucleated osteoclasts are markedly increased in number and activity causing bone resorption. Osteoblasts then respond in turn, producing weak disorganised woven bone. This sequence of events is repeated several times producing abnormally large deformed bones with increased vascularity
How does Paget’s disease present?
3 options
1 - symptomatic patients complain of pain, warmth and tenderness over the affected limb
2 - with a complication such as a fracture or deformity
3 - as an incidental finding
What are the symptoms of a symptomatic patient?
bone pain - commonly waxing and waning
joint pain - if involved bone is close to the joint, leading to damaged cartilage and OA
deformities - bowed tibia, skull changes
What are the complications of paget’s disease?
nerve decompression - deafness from CN VIII involvement.
increased bone blood flow - myocardial hypertrophy, high output cardiac failure
pathological fractures
What investigations are used in pages disease?
X-ray - sketch survey is required
Bone scans - demonstrates extent of involvement
Serum ALP - increased
Mild hypercalcaemia in very extensive disease
Urine - raised urine hydroxyproline due to increased bone turnover
What is shown in the blood results of someone with Paget’s?
Serum ALP increased with normal calcium and phosphate due to increased bone turnover. Can be used as a marker for treatment and relapse
What is the treatment for Paget’s disease?
1) Simple analgesics for bone pain
2) Bisphosphonates (MAIN STAY)
3) Monitor serum ALP regularly with urinary hydroxyproline excretion
4) Treatment of asymptomatic patients is appropriate as risk of complications like fractures
5) Surgery
How are bisphosphonates given to patients with Paget’s disease?
IV is very effective - give for 6 weeks and repeat after 6 months if required
Oral is effective - give for 12 weeks and repeat after 6 months if needed
What surgery is used in Paget’s disease?
Osteotomy may be needed for secondary joint disease
Intra-articular lidocaine to differentiate between bone and joint disease
Neurosurgery for spinal disease
Osteosarcoma may need amputation
What is primary osteonecrosis?
Avascular necrosis
Bone death resulting from poor blood supply to an area of bone
What is the natural history of osteonecrosis?
1) bone death without structural change
2) repair and early structural repair
3) major structural repair
4) articular destruction
What are the risk factors for primary osteonecrosis?
bone fracture idiopathic syndromes exogenous corticosteroid therapy alcohol abuse infection (septic arthritis) marrow infiltration (malignant disease and gaucheries' disease)
What are the target sites for primary osteonecrosis?
femoral head femoral condyles head of humerus proximal pole of the scaphoid proximal pole of the talus
all lie on the outskirts of the bones main vascular supple and are enclosed by articular cartilage which itself is avascular
How would a patient with osteonecrosis present?
often well advanced at presentation pain near joint stiffness in the joint local tenderness and swelling of a nearby joint restricted movement
What are the investigations needed in suspected osteonecrosis?
x-ray (changes only present after several months) MRI (to pick up early osteonecrosis) Radionuclear scanning (diminished activity in the avascular segment but more often increased activity due to vascular reaction)
How is osteonecrosis treated?
no treatment needed for the upper limb
eliminate the cause
stage 1 or 2: bone collapse may be eliminated by weight relief, splinting and surgical decompression
stage 3: realignment osteotomy can be done to transfer stress to an undamaged area and relieve pain
if articular cartilage destruction, treat as OA
