metabolic bone disease Flashcards
what cell forms bone
osteoblasts
what cell breaks down bone
osteoclasts
what is the test for vitamin D
25OH vit D
what is pagets disease of bone
localised disorder of bone turnover
increased bone resorption followed by increased bone formation
bigger, less compact, more vascular and more susceptible to deformity and fracture. not organised so some areas high density (sclerosis) some area lows ( lysis)
epidemiology of pagets
relatively common
strong genetic
UK and east coast of US and australia and NZ
possibility of chronic viral infection within osteoclast
investigations pagets
xray- bone enlargement and deformity, cotton wool appearance of skull, V shaped defects in long bones
isotope bone scan
raised alkaline phosphotase
normal calcium
normal phosphate
pagets disease signs
always patient >40years
constant bone pain sometimes worse at night
elevated serum alkaline phosphotase (LFT)
bone pain and local heat
bone deformity and local heat
hearing loss
osteosarcoma in affected bone RARE but lethal
can have no symptoms
particularly affects axial skeleton
treatment of pagets
asymptomatic dont treat unless in skull
do not treat based on alkaline phosphotase alone
IV bisphosphonate therapy- one off zoledronic acid infusion
monitor ALP levels
what is rickets and osteomalacia
severe nutritional vit D or calcium deficiency
rickets in growing child
osteomalacia in adult (when epiphyseal lines are closed)
rickets signs and symptoms
large forehead
odd shaped ribs and breast bones
large abdomen
stunted growth
wide joints at elbow and wrists
odd shaped legs
failure to thrive
osteomalacia signs and symptoms
bone pain
muscle weakness
increased falls risk
holes in skull- pepper box skull
treatment for rickets and osteomalacia
calcium and vit D supplements
what is osteogenesis imperfecta
genetic disorder of connective tissue. broad clinical age range
brittle bone disease
signs of osteogenesis imperfecta
fragile bones from mild trauma and even acts of daily life
growth deficiency
hearing loss
blue whites of eyes
scoliosis
barrel chest
hypermobility
easy bruising
types of OI
8 types. 4 most common
1- milder form child starts to walk and can present in adults
2- lethal by age 1
3- progressive deforming with severe bone dysplasia and poor growth
4- more severe type 1
managment of OI
surgery to treat fractures
IV bisphosphonates to prevent fractures
no team sports or PE for children
genetic counselling
what is osteoporosis
reduction in the density of the bones leading to enhanced bone fragility and fracture risk
DXA bone scan osteoporosis result
less than -2.5 SDs below the young adult mean in post menopausal woman (want z score to be 0)
investigations
fracture risk calculators-
WHO fracture risk assessment tool FRAX
Q fracture
prodigy scanner
DXA scan of spine - want z score to be 0
management of osteoporosis
fracture risk assessment tool to find if at risk of osteoporosis
then if significant risk (>10% risk of fracture over 10 years) then refer for DXA scan
all on oral steroids or suffer a low trauma fracture should be referred anyway
endocrine causes of osteoporosis
thyrotoxicosis
hyper and hypoparathyroidism
cushings
hyperprolactinoma
hypopituitarism
low sex hormone levels
rheumatic causes of osteoporosis
rheumatoid arthritis
ankylosing spondylitis
polymyalgia rheumatica
GI causes of osteoporosis
UC and crohns
PBC, CAH, alcoholic cirrhosis, viral cirrhosis
CF
coeliac
chronic pancreatitis
whipples disease
ischemaic bowel
meds that cause osteoporosis
steroids
PPI
enzyme inducting antiepileptic meds
aromatase inhibitors
GnRH inhibitors
warfarin
risk factors
old age
female
previous fractures
low BMI
RA
alcohol and smoking
long term steroids
management of osteoporosis
reduce fracture risk
good calcium and vit d
bisphosphonates- ate
HRT
SERM - raloxifene
what is a low bone density but not osteoporosis yet called
osteopenia
side effects of bisphosponates
all rare
reflux and oesophageal erosions
atypical fractures
osteonecrosis of jaw or ear
need good renal function
need drug holiday for 1-2 years after 10 years therapy
examples of bisphosphonates
alendronate
risedronate
zoledronic acid (IV)
