Osteoporosis Flashcards
What is the definition of osteoporosis?
a condition of skeletal fragility characterised by reduced bone mass and micro-architectural deterioration predisposing to an increased risk of fractures
WHO defines osteoporosis by bone mineral density (BMD) measurement, which allows diagnosis and treatment of osteoporosis prior to incident fracture
What are the clinical features of osteoporosis?
Asymptomatic
Pain or loss of height with development of kyphosis cause by fragility fractures
Features of underlying disease eg. Cushing’s syndrome
How is osteoporosis diagnosed?
Clinical significance lies in the fractures that occur- vertebrae, hip and wrist (colles fractures)
BMD measured using dual-energy absorptiometry (DEXA) scanning
Osteoporosis- T-score -1
Use Z score for patient less than 50 years old
What investigations need to be carried out for osteoporosis?
Renal function test
Bone profile- calcium, Vitamin D, phosphate, alkaline phosphate & parathyroid hormone
Thyroid function test
Bone turnover markers
Multiple myeloma screen- ESR, Serum immunoglobulins and protein electrophoresis & urinary Bence Jones protein
Consider cortisol, testosterone, oestradiol, PSA, tTG
What is the aetiology of osteoporosis?
Drugs: steroid, sex hormone antagonist, lithium, anti-convulsant and heparin
Endocrine: Cushing, Acromegaly, Hypopituitarism and Prolactinoma
Inflammatory: Rheumatoid arthritis, Ank spondylitis and IBD
Nutritional: Vit D, Ca and malabsorption syndrome
Genetic: Marfan, Osteogenesis imperfecta and Turner syndrome
What are the risk factors for osteoporosis?
Previous fracture Family history Excess alcohol Smoking Corticosteroid treatment Amenorrhoea for 6 months (excluding pregnancy) Late menarche Early menopause including surgical menopause Immobility/ physical inactivity Drugs: heparin, phenytoin Inflammatory arthritis-rheumatoid arthritis, ankylosing spondylitis Gastrectomy
What are the consequences of osteoporosis?
Diminshed quality of life due to pain and kyphosis
Decreased independence- decreased ability to bathe, dress and ambulate independently
Increased morbidity
Increased mortality- related to hip fractures – 20% excess mortality in the year following hip fracture
Approximately 50% not recover prior function
What are the lifestyle modifications to help improve osteoporosis?
Improve calcium intake- 1200-1500ml/day of milk
Weight-bearing exercises
Smoking cessation
Reduction of alcohol consumption if excessive
Which medications are used to treat osteoporosis?
Vitamin D & calcium supplement
Bisphosphonates- they incorporate into Ca2+ at the bone matrix, during resorption they enter the clasts and induce apoptosis, they do not interfere with bone physicochemical properties
Selective oestrogen receptor modulators (SERMs)- Raloxefine
Strontium
HRT
Testosterone treatment
Parathyroid hormone
What are the secondary causes of osteoporosis?
Drug:
Steroids, sex hormone antagonist, lithium, anticonvulsants, heparin
Endocrine:
Cushings, Hyperthyroid, Hyperparathyroid, Prolactinoma, Diabetes, Hypogonadism
Smoking:
Inflammatory:
Rheumatoid arthritis, Ankylosing spondylitis, IBD
Nutritional:
Vit D def, Ca def, malabsorption syndrome (Coeliac, IBD, chronic pancreatitis), low BMI
Genetic:
Marfans, Osteogenesis imperfecta, Turner
Haematological:
Myeloma
Alcohol excess
Menarche:
Amenorrhoea for 6 months (excluding pregnancy), late menarche, early menopause including surgical menopause
Who should be screened for primary prevention of osteoporosis?
All women > 65, men > 75 Previous fragility fracture Current or frequent use of systemic steroids History of falls Family history of hip fracture Other causes of secondary osteoporosis Low BMI (<18.5kg/m2) Smoking Alcohol Women > 14 units / week Men > 21 units / week
What re the commonly used bisphosphonates?
Alendronate / Risedronate / Zolendronate (IV)
Cause osteoclast apoptosis
Advice: Upright, empty stomach, full glass of water, 30minutes
Side effects:
GORD
Atypical fractures (hip, femur)
Osteonecrosis of the jaw
IV zoledrenate:
Increased absorption, reduced side effects
Hypocalcaemia, limited number of doses (3 in total)
When are bisphosphonates recommended?
if 10 year risk of osteoporotic fracture is >1%
IV Bisphosphonate recommended if 10 year probablity of osteoporotic fracture is >10% or >1% + intolerant of oral bisphosphonate
Which selective oestrogen receptor modulators (SERM) are used?
Raloxifene
If bisphosphonates intolerable
Oestrogen mimicking effects on bone
Side effects – hot flushes, leg cramps, blood clots
What is denosumab?
Second lien treatment
Monoclonal antibody which inhibits the cells that break down bone (osteoclasts) and as a consequence prevents bone loss. It does this by blocking a protein that is involved in stimulating bone resorption known as RANK ligand
6 monthly SC injections
Side effects: hypocalcaemia, cellulitis
