Metabolic bone disease Flashcards
what is the main function of vitamin D?
Ca reabsorption from the gut
what is Paget’s disease?
localised disorder of bone turnover
increased bone resorption followed by increased bone formation
leads to disorganised bone- bigger, more vascular, less dense, deformity and fracture risk
what is the presentation of Paget’s disease?
patient > 40 years but < 60 yrs
bone pain - constant deep seated pulsating pain
occasionally bone deformity
excessive heat over pagetic bone
neurological complications such as nerve deafness
what is the main clinical signs of Paget’s disease?
increased serum alkaline phosphatase
what is the treatment of Paget’s disease?
no treatment is asymptomatic unless in skull
treatment with bisphosphonates - one off IV zoledronic acid
what is rickets and osteomalacia caused by?
severe vitamin D or calcium deficiency which causes insufficient mineralisation
what can be seen on x-ray which suggests osteomalacia?
looser zones
pseudo fractures which occur in proximal femur, ulna, ribs, lateral scapula etc
they never become full fractures
what is osteogenesis imperfecta?
genetic disorder of type 1 collagen characterised by fragile bones from mild trauma and even acts of daily life
what are the 4 most common types of osteogenesis imperfecta?
type 1: milder form
type 2: lethal by age 1
type 3: progressive deformity with severe bone dysplasia and poor growth
type 4: similar to type 1 but more severe
what are the signs/symptoms of osteogenesis imperfecta?
fractures from normal daily life or mild trauma growth deficiency defective tooth formation (dentigenesis imperfecta) hearing loss blue sclera scoliosis barrel chest ligamentous laxity (hypermobile) easy bruising
what scoring system is used to determine if someone is hyper mobile and what bone condition is this found in?
osteogenesis imperfecta
- The Beighton Score
what is the management for osteogenesis imperfecta?
surgical to treat fractures
medical to prevent fractures - IV bisphosphonates
social adaptations
genetic counselling for parents and children
what percentage of Paget’s disease cases are familial?
15-30%
- requires evironmental trigger i.e. chronic infection in susceptible individuals
what is osteoporosis?
metabolic bone disease characterised by low density bone mass and micro architectural deterioration of bone
leads to enhanced fragility and therefore increased risk of fracture
what result on a DXA scan is indicative of osteoporosis?
< -2.5 SDs
blow the young adult mean score in a post menopausal woman (T-score)
this basically means that their bone mass has decreased more than 2.5 SDs since they were a young adult and this amount of decrease is indicative of osteoporosis
what factors are related to risk of fracture?
age
bone mass density
fals
bone turnover
what investigations can you carry out to diagnose osteoporosis?
DXA scan
isotope bone scan
how common is osteoporosis in men and women?
1 in 2 women and 1 in 5 men will have osteoporotic fracture after 50
what are the endocrine causes of osteoporosis?
thyrotoxicosis hyper and hypoparathyroidism bushings hyperprolactinaemia hypopituitarism early menopause
what are the rheumatic causes of osteoporosis?
rheumatoid arthritis
ankylosing spondylitis
polymyalgia reumatica
what are the GI causes of osteoporosis?
inflammatory: UC and crohns
liver: PBC,CAH, alcoholic cirrhosis, viral cirrhosis (hep C)
malabsorption: chronic pancreatitis, coeliac disease, whiles, ischaemic bowel, short gut syndrome
what medications can cause osteoporosis?
steroids PPI enzyme inducing antiepileptic drugs i.e. phenytoin aromatase inhibitors GnRH inhibitors warfarin
how we measure someones bone mass density?
DXA scan
when is someone treated for osteoporosis?
when their DXA scanning and report-fracture risk is 20% 10 year risk
what are the treatment options for osteoporosis?
hormone replacement therapy selective oestrogen receptor modular bisphosphonates monoclonal antibodies i.e. Denosumab intermittent human parathyroid hormone i.e. Teriparatide
what are the side effects of HRT?
blood clots
increased risk of breast cancer/prostate cancer
increased risk of heart disease and stroke if used after a large gap from menopause
what are the side effects of SERM’s?
hot flushes if taken close to the menopause
increased clotting risk
no protection at hip site (doesn’t protect against fractures)
what are the side effects of bisphosphonates?
oesophagi’s
atypical femur fracture
iritis/ uveitis
osteoporosis of the jaw
