disorders of bone health Flashcards
what are osteoblasts?
bone forming cells
what are osteoclasts responsible for?
bone breakdown/reabsorption
what are osteocytes?
mature bone cells within the bone matrix, help to maintain bone and act as mechanosensors
which drugs can cause bone mass loss?
glucocorticoids
what are the common fracture sites?
Neck of femur
Vertebral body
Distal radius
Humeral neck
what are the non modifiable risk factors for fractures?
Age
Gender
Ethnicity
Previous fracture
Family history
Menopause ≤ 45 years
Co-existing diseases
what are the modifiable risk factors for fractures?
BMD (bone mineral density)
Alcohol
Weight
Smoking
Physical inactivity
Pharmacological risk factors
who gets referred for DEXA?
patients over 50with low trauma fracture
people who have a risk >10% over a 10 year period
what is the clinical range for osteopenia?
BMD>1 SD below young adult mean but <2.5 below this value
what is the clinical range for osteoperosis?
BMD ≥ 2.5 SD below the young adult mean
if the patient is younger than 20, which score is reported?
Only the Z score
what are the secondary causes of osteoperosis?
endocrine eg hyperthyroidism, cushings disesase
GI eg coeliac, IBD chronic liver disease
respiratory eg COPD
chronic kidney disease
what is the lifestyle advice for management of osteoperosis?
High intensity strength training
Low-impact weight-bearing exercise (standing, one foot always on the floor)
Avoidance of excess alcohol
Avoidance of smoking
Fall prevention
what are the drug treatments for osteoperosis?
Calcium & vitamin D supplementation
Bisphosphonates
Denosumab
Teriparatide
Romosozumab
HRT
Testosterone
how do biphosphonates work?
ingested by osteoclasts leading to cell death
thereby inhibiting bone resorption
what are some examples of biphosphonates?
alendronate
risedronate
both taken 1 per week
what are the side affects of biphosphonate therapy?
osteonecrosis of jaw
oesophageal Ca
what is an alternative to biphosphonates?
zoledronic acids (IV done if people cant tolerate biphosphonates)
denosumab (SC monoclonal antibody)
what are the direct effects of corticosteroids on the bone?
Reduction of osteoblast activity and lifespan
Suppression of replication of osteoblast precursors
Reduction in calcium absorption
what are the indirect effects of corticosteroids on the bone?
inhibition of gonadal and adrenal steroid production
what % of BMD is lost in the first 6 months of use of corticosteroids?
30%
what bones does pagets disease primarily affect?
long bones
pelvis
lumbar spine
skull
what causes pagets disease?
unknown aetiology
how does pagets disease present
bone pain, deformity, deafness, compression neuropathies
what is a rare complication of pagets disease?
osteosarcoma
how is pagets treated?
with biphosphonates if pain not responding to analgesia?
what happens in pagets disease?
Abnormal osteoclastic activity followed by increased osteoblastic activity
what is osteogenesis imperfecta?
a rare group of genetic disorders mainly affecting bone
what mutations tend to cause osteogenesis imperfecta?
type 1 collagen mutations (COL1A1 and COL1A2)
what pattern of inheritance does osteogenesis imperfecta follow?
autosomal dominant
what can osteogenesis imperfecta be associated with?
blue sclerae and dentinogenesis imperfecta
