Metabolic Bone Disease Flashcards
what causes paget’s disease?
> genetic
> chronic viral infection of the osteoclasts
what is the pathophysiology of paget’s disease?
localised disorder of bone turnover.
increased bone resorption
increased bone formation
leading to disorganised bone that is bigger, more vascular and less compact.
how does paget’s disease present?
> more than 40 years old > bone pain > deformity > heat > neurological complications (deafness) > (osteosarcoma)
how would you isolate pagets disease?
isolated elevated serum alkaline phosphatase
how do you treat paget’s disease?
> nothing unless symptomatic or in the skull
> one off zoledronic acid infusion
describe the pathophysiology of rickets
insufficient vitamin d or calcium in a child leads to insufficient mineralisation causing rickets
what is the pathophysiology of rickets?
same process of insufficient vit. d and calcium but with fused epithelial plates
how does rickets present?
> wide bones
stunted growth
bow legs
large abdomen
how does osteomalacia present?
> bone pain
muscle weakness
increased falling
what is osteogenesis imperfecta?
genetic disorders of the connective tissue causing type one collagen defect and fragile bones from the everyday trauma of life
what is type one osteogenesis imperfecta?
> milder form
> presents when child starts to walk or in adults
what is type two osteogenesis imperfecta?
lethal by age one
what is type 3 osteogenesis imperfecta?
progressive deforming with severe bone dysplasia and poor growth
how does osteogenesis imperfecta present?
> growth deficiency > defective tooth formation > hearing loss > blue sclera > scoliosis (barrell chest) > easy bruising > ligamentous laxity
how is osteogenesis imperfecta managed?
> surgically to fix fractures
genetic counselling
social adaption and education
IV bisphosphonates to prevent fractures
what are some endocrine causes of osteoporosis?
> thyrotoxicosis > cushing's > hyperparathyroidism > hypoparathyroidism > hyperprolactinaemia > hypopituitarism > low sex hormone levels
what are some rheumatic causes of osteoporosis?
> rheumatic arthritis
ankylosing spondylitis
polymyalgia rheumatica
what are some gastrointestinal causes of osteoporosis?
> IBD > primary biliary cholangitis > chronic active hepatitis > viral hepatitis > coeliac > CF > chronic pancreatitis > whipples disease > short gut syndrome > ischaemic bowel
what medication can cause osteoporosis?
> warfarin > steroids > PPI > enzyme inducing antiepileptic medication > aromatase inhibitors > GnRH inhibitors
what is osteoporosis?
metabolic bone disease characterised by low bone mass and microarchitectural deterioration of bone tissue leading to bone fragility and fracture risk
what are the risk factors for fractures in osteoporosis?
> age
BMD
falls
bone turnover
how do you assess fracture risk in osteoporosis?
DXA scan
how can you prevent fractures?
> minimise risk factors > ensure good vitamin D and calcium status > HRT > BISPHOSPHONATES > denosumab > teriparatide
what are the side effects of HRT?
> increased risk of blood clots
increased risk of breast cancer
increased risk of stroke
increased risk of heart disease
what does bisphosphonate therapy require?
> adequate renal function
adequate calcium and vitamin d status
good dental health and hygeine
what are the side effects of bisphosphonates?
> oesophagitis > iritis > uveitis > atypical femoral shaft fractures > osteonecrosis of the jaw
what is denosumab?
> monoclonal antibody against RANKL
true or false
denosumab is safer in patients in renal impairment than bisphosphonates
true
