Metabolic Bone Disease Flashcards
What does vitamin D stimulate?
Absorption of calcium and phosphate from the gut, which then become available for bone mineralisation
What is rickets?
Sever nutritional vitamin D or calcium deficiency causes insufficient mineralisation and thus rickets in a growing child
What is osteomalacia?
Severe nutritional vitamin D or calcium deficiency causing insufficient mineralisation in an adult when the epiphyseal lines are closed
What is Paget’s disease?
Localised disorder of bone turnover
Increased bone resorption followed by increased bone formation
Leads to disorganised bone; bigger, less compact, more vascular and more susceptible to deformity and fracture
What are the clinical features of Paget’s disease?
Patient >40 Bone pain Excessive heat over pagetic area Bone deformity Neurological complications (nerve deafness)
What is the presentation of Paget’s disease?
Isolated elevation of serum alkaline phosphatase
Bone pain and local heat
Bone deformity or fracture
Hearing loss
Osteosarcoma development in affected bone
What is the treatment for Paget’s disease?
IV bisphophonate therapy- one off IV zoledronic acid
What is osteogenesis imperfecta?
Genetic disorder of connective tissue characterised by fragile bones from mild trauma due to defects in type 1 collagen
What are the signs and symptoms of osteogenesis imperfecta?
Growth deficiency Defective tooth formation (dentigenesis imperfecta) Hearing loss Blue sclera Scoliosis Barrel chest Ligamentous laxity Easy bruising
What is the management of osteogenesis imperfecta?
Surgical treatment of fractures
IV bisphosphonates to prevent fractures
What is osteoporosis?
Microarchitectural deterioration of bone resulting in increased risk of fracture
What are the risk factors for fractures?
Age
Bone mineral density (BMD)
Falls
Bone turnover
What is FRAX?
Fracture risk assessment tool
What are the limitations of FRAX?
Doesn’t accommodate all known risk factors
Lacks detail on some risk factors
Depends on adequacy of epidemiological information
Does not replace clinical judgement
What are the causes of secondary osteoporosis?
Hyperthyroid, hyperparathyroid, hypoparathyroid
Coeliac
Cystic fibrosis
Myeloma
Rheumatoid arhtitis
Anklyosing spondylitis
Steroids, heparin, warfarin, anticonvulsants
Anorexia nervosa, early menopause, primary ovarian failure
How can osteoporosis be prevented?
Minimise risk factors
Ensure good calcium and vitamin D status
Falls prevention strategy
Medication
What medications will help osteoporosis?
HRT
What are the side effects of HRT?
Increased risk of blood clots
Increased risk of breast cancer with extended use into late 50s/60s
Increased risk of heart disease and stroke if used after large gap from menopause
What are the side effects of selective oestrogen receptor modulator?
Hot flushes if taken close to menopause
Increased clothing risks
Lack of protection from hip site
What must be in place before taking bisphosphonates?
Adequate renal function required
Adequate calcium and vitamin d required
Good dental health and hygiene advised
What are the side effects of bisphosphonates?
Oesophagitis
Iritis/uveitis
What are the side effects of teriparatide?
Injection site irritation
Rarely hypercalcaemia
Allergy
What is denosumab?
Monoclonal antibody against RANKL
What is the function of denosumab?
Reduces osteoclastic bone resorption