Osteoporosis, Pagets, Osteogenesis Imperfecta Flashcards
What is osteoporosis?
systemic skeletal disease, characterised by low bone mass and microarchitetural deteriation of bone tissue which leads to increased bone fragility and susceptibilty to fracture
What is the role of osteoclasts during bone remodelling?
reabsorb the bone
What is the role of osteoblasts during bone remodelling?
replace the cavity formed by the osteoclasts by laying down osteoid that is then mineralised to new bone
What is required for normal bone turnover?
complete balance between osteoclasts and osteoblasts
What is the bone turnover situation in osteoporosis?
more osteoclasts than osteoblasts
What factors can cause bone loss?
sex hormone deficiency genetics body weight immobility glucocorticoids aromatase inhibitors
How is bone density assessed?
DEXA bone scan measures the BMD (fracture risk)
What is does a high T score indicate?
high fracture risk
How is osteoporosis diagnosed by BMD?
> 2.5 SDs below the young adult mean
How is osteomalacia diagnosed by BMD?
> 1 SD below the young adult mean
What does a low BMD indicate?
low fracture risk
What is the non pharmacological treatment for osteoporosis?
change modifyable factors eg alcohol, smoking, physical inactivity
high intensity muscle training
low impact weight bearing exercise
700mg calcium daily
What is the pharmacological treatment for osteoporosis?
calcium and vit D supplements
Biphosphonates - anti reabsorptive agents (ingested by osteoclasts leading to their cell death)
Zoledronic Acid - IV infusion
Denosumab - monoclonal antibody - inhibits activity of osteoclasts
Teriparaticle - recombinant parathyroid hormone that stimulates bone growth
What is Pagets disease?
abnormal osteolastic activity that is then followed by abnormal osteoblastic activtiy leading to an abnormal bone strength
What is wrong with the bone in pagets disease?
there is an increased fracture risk
reduced strength
What bones are normally affected by pagets disease?
long bones
pelvis
lumbar spine
skull - hearing loss
What is the age normally affected by pagets?
> 40
How does pagets present?
bone pain
deformity
deafness
compression neuropathy
How is pagets diagnosed?
X ray
isolated bloos All phos
isotope bone scan will show the disease distribution
How is pagets treated?
analgesia for pain
biphosphonates
What are the genes that are mutated in Osteogenesis imperfecta?
AUTOSOMAL DOMINANT
secondary to mutations of type 1 collagen genes (COLLA1, COLLA2)
What are type 1-4 of Osteogenesis imperfecta?
1: mild
2: neonatal - lethal
3 and 4: very severe - most common
How does Osteogenesis imperfecta present?
most severe -> fractures in childhood
mild form -> fractures in adulthood
blue scelrae and detinogenesis imperfecta (discoloured teeth)
What is the treatment for Osteogenesis imperfecta?
fracture fixation
surgery to perfect deformities
biphosponates
NO CURE
