Metabolic Bone Disease Flashcards
What is osteoporosis?
Reduction in the density of bones
Most common metabolic bone disease
What is the consequence of osteoporosis?
Enhanced bone fragility and more prone to fractures
What are the risk factors for osteoporosis?
Old age
Female
Reduced mobility and activity
Low BMI
RA
Alcohol and smoking
Long term steroids
SSRIs, PPIs, anti-oestrogens
What is a key group to consider in osteoporosis?
Post- menopausal women
Oestrogen is protective against osteoporosis
Postmenopausal women have less oestrogen
What is FRAX tool?
Prediction of the risk of a fragility fracture over the next 10 years
What are the components of FRAX?
Age
BMI
Comorbidities
Smoking
Alcohol
FH
What is a DEXA scan?
Dual- energy X ray absorptiometry
Measure bone mineral density (BMD)
What is the first step in assessing osteoporosis?
Perform a FRAX assessment on at risk patients
What lifestyle changes are used for osteoporosis management?
Activity and exercise
Maintain a healthy weight
Adequate calcium intake
Adequate vitamin D
Avoiding falls
Stop smoking
Reduce alcohol consumption
What medical options are used for osteoporosis?
Vitamin D and Calcium
Bisphosphonates
Denosumab
Raloxifene
HRT
Describe bisphosphonates
First line treatment
Interfere with osteoclasts preventing bone resorption
Describe bisphosphonates
First line treatment
Interfere with osteoclasts preventing bone resorption
E.g. Alendronate
What are the side effects of bisphosphonates?
Reflux and oesophageal erosions
Atypical fractures
Osteonecrosis of the jaw
Osteonecrosis of the external auditory canal
Describe denosumab
Monoclonal antibody that blocks osteoclast activity
Describe raloxifene
Selective oestrogen receptor modulator- stimulates oestrogen receptors on bone
Secondary prevention only
Describe HRT
Use din early menopause women
What is osteomalacia?
Condition where there is defective bone mineralisation causing ‘soft’ bones
What causes osteomalacia?
Insufficient Vitamin D
What is the role of vitamin D in normal physiology?
Vitamin D is essential in calcium and phosphate absorption from the intestines and kidneys.
It is also responsible for regulating bone turnover
What is the pathophysiology of osteomalacia?
Inadequate vitamin D leads to a lack of calcium and phosphate
Results in defective bone mineralisation
Low calcium causes hyperparathyroidism leading to increased bone reabsorption
What patients are at risk of osteomalacia?
Darker skin- require a longer period of sun exposure to generate the same quantity of Vitamin D
Malabsorption disorders- reduced Vitamin D from diet
Chronic kidney disease- reduced Vitamin D metabolism
What is the presentation of osteomalacia?
Fatigue
Bone pain
Muscle weakness
Muscle aches
Pathological fractures
What investigation results are seen in osteomalacia?
Low serum 25-hydroxyvitamin D (<25nmol/L)
Low serum calcium
Low serum phosphate
High serum ALP
High PTH
DEXA shows low BMD
X rays show osteopenia
What is the treatment of osteomalacia?
Supplementary Vitamin D (colecalciferol)
