Metabolic Bone Disease Flashcards
What are some causes of acute onset of severe back pain?
Acute disc disruption +/- nerve root compression
Acute vertebral fracture
Bony metastases
What is the likely cause of height loss?
Loss of height of vertebrae/intervertebral disc spaces
What are common sites of compression fractures, and why?
Lower thoracic
Upper lumbar
Spine more mobile
What are the the three most common endocrine diseases, and are also associated with osteoporosis?
Diabetes
Thyroid disease (mainly hyper)
Primary parathyroid disease
What is the investigation used to diagnose osteoporosis?
X-ray
What is the investigation used to screen for osteoporosis?
Bone densitometry
What is the WHO criteria for osteoporosis?
Normal = equal to or more than -1 T-score
Osteopaenia = between -2.5 and -1 T-score
Osteoporosis = equal to or less than -2.5 T-score
Severe osteoporosis = equal to or less than -2.5 T-score and 1+ fracture
What is the Z-score in DXA testing?
Number of standard deviations above and below mean for patient’s age, sex, and ethnicity
What is the T-score in DXA testing?
Number of standard deviations above and below mean for healthy 30 year old adult of same sex and ethnicity as patient
How can the Z-score be useful in identifying underlying accelerated causes of bone loss?
Score of
What is DXA?
Dual energy x-ray absorptiometry
What is P1NP?
Bone formation marker
What is CTX?
Bone resorption marker
What are the common secondary causes of osteoporosis?
Cushing's syndrome Exogenous corticosteroids Excessive alcohol use Smoking Malabsorption Primary/secondary hypogonadism
What are the less common secondary causes of osteoporosis?
BMI <20 and associated eating disorders Lack of/excessive exercise Thyrotoxicosis/thyroxine over-replacement Primary hyperparathyroidism Chronic liver/kidney disease Hypercalciuria Rheumatoid arthritis/ankylosing spondylitis T1 and T2D Multiple myeloma HIV/its treatment Mastocytosis Organ transplant/immunosuppressive drugs Osteogenesis imperfecta
How do you decide on appropriate treatment for osteoporosis?
Patient's/family's wishes Benefit/risk ratio for each treatment Severity of disease Prior treatment Co-morbidities that might influence choice of medication
What are the goals of management in osteoporosis?
Fracture risk reduction
Avoid hip fractures > reduction in mortality
Improve quality of life
- Preserve mobility and independence
How do hormone replacement therapy (HRT) and selective oestrogen receptor modulators (SERMs) work?
Stimulate osteoblast activity
How do bisphosphonates work?
Inhibit osteoclast formation
Induce osteoclast apoptosis
How does denosumab work?
Binds RANKL > osteoclasts not activated
How does teriparatide work?
PTH analogue, given intermittently
Stimulates osteoblasts
How does strontium work?
Stimulates osteoblasts
Inhibits osteoclast formation
What are the contraindications and relative contraindications for strontium use in women?
Contraindications
- History of ischaemic heart disease/peripheral venous disease/cardiovascular disease
- HTN
Relative contraindications
- Significant risk factors for cardiovascular events
How are bisphosponates excreted?
Renally
How is osteoporosis treatment different in chronic kidney disease?
Stage 1-3a = same as patients without chronic kidney disease
Stage 3b = Caution with IV bisphosphonates; dose reduction with oral bisphosphonates
Stage 4 = bisphosphonates with hypocalcaemia precaution
Stage 5 = no data
What are the presentations at different stages of osteonecrosis of the jaw?
Stage 1 = asymptomatic
Stage 2 = pain and inflammation/infection
Stage 3 = pain and inflammation/infection, and osteolysis
What are the risk factors for osteonecrosis of the jaw?
IV bisphosphonates Prolonged bisphosphonates Steroids Smoking Poor oral hygiene
