metabolic bone disease Flashcards
vit D
Skin 7DHC
Liver 25(OH) vit D
Kidney 1,25(OH) 2 Vit D
Rickets (kids) and osteomalacia (adults)
severe nutritional vit D or calcium deficiency
vit D absorption calcium and phosphate from gut and bone mineralisation
impaired muscle function
Paget’s disease
localised disorder of bone turnover
increased bone resorption followed by increased bone formation
disorganised bone: bigger, less compact,more vascular, susceptible to deformity
-strong genetic
>40 years with bone pain, deformity
neurological complication nerve deafness
isolated elevation of serum alkaline phosphatase- common presentation
treatment: intravenous bisphosphonate therapy
zoledronic acid
osteogenesis imperfecta
connective tissue disorder
fragile bones
defect in type 1 collagen-
Type 1- milder form
type 11- lethal by age 1
type 111- progressive deforming with bone dysplasia and poor growth
type 4 - similar to type 1 but more severe
signs/symp
blue sclera scoliosis bareel chest easy brusing imperfect tooth formation treatment surgical medical social genetic
osteoporosis
metabolic bone disease- low bone mass, micro architecural deterioration of bone tissue leading to fragility and increased fracture risk
DXA< -2.5 (T score)
risk of fracture:
Age, BMD; Falls; Bone turnover
NICE document/ risk assessment
assessment of fracture
looked at the different methods of doing this and all the different potential risk factors for thin bones FRAX
FRAX
Fracture Risk Assessment Tool
limitations: does not accommodate all known risk factors: falls, biochemical markers
Lacks detail on some risk factors
depends on adequacy of epidemiological information
limited country models available model relevant only for untreated patients
secondary osteoporosis
endocrine: thyroid, cushings Malabsorption: coeliac malignancy: myeloma Rheumatic Drugs: steroids, heparin, wrfarin Amenorrhoea: anorexia
side effects of HRT
increased risks of blood clots increased risk of breast cancer with extended use into late 50s
increased risk of heart disease and stroke after large gap from menopause
main treatment
Bisphosphonates oral adequate renal function required adequate calcium and vit D status good dental health and hygiene advised nitrogen containing bisphophonates inhibit osteoclasts
side effects of bisphophonates
oesophagitis
iritis/ uveitis
ONJ
atypical femoral shaft fractures
teriparatide (Cost)
parathyroid hormone consisting of the first (N-terminus) 34 amino acids, which is the bioactive portion of the hormone. It is an effective anabolic (promoting bone formation) agent used in the treatment of some forms of osteoporosis.
Denosumab
monoclonal antibody against RANKL
factors which stimulate osteoblast expression of RANK ligand
PTH, PGE2, Glucocorticoids, Vit D, IL-11, IL-1, PTHrP
TNF alpha
symptomatic hypocalcaemia if given when vitamin D deplete
