Disuse and Hormonal based Osteoporosis Flashcards
Describe osteoporosis?
A skeletal disorder characterised by low bone material density BDM and microarchitectural deterioration of bone tissue which increases the risk of fractures
Bone density value more than 2.5 SD below the young adult mean value.
What is FRAX?
Evaluates fracture risk factor
What has to happen for a fracture to occur?
You have to surpass a certain none fracture threshold.
What are the main factors of accelerated bone loss?
Think menopause/deficiencies
Estrogen deficiency
calcium and Vit D deficiency
Secondary Hyperparathyroidism
Cytokines
What are the main factors of inadequete formation response during bone remodelling?
Imparied cell renewal
Increase in adipogenesis
Decreased growth factors
Cytokines
What effects does E (oestrogen) have on bone formation?
Promotes differentiation of bone marrow cells towards the osteoblast lineage
increases collegen production by osteoblasts
increases diff of osteoblasts
Increases blasts and cytes life span
Increases blasts production of growth factors IGF-1 TGF-beta.
What are the effects of E2 (estrodiol) deficiency on bone?
Increase in bone remodelling
Bone remodelling imbalance
Bone formation increases by 45%, and bone resorption by 90%
E2 acts directly through receptors expressed by osteoblasts and clasts
What effects does E have on bone resorption?
Inhibits osteoclastogenesis by modulating levels of cytokines produced by bone marrow stromal cells and immune cells
Inhibits osteoclasts function and promotes osteoclast function and promotes osteoclast apoptosis
What is the effect of osteoblasts by testosterone?
Stimulates osteoblast proliferation and limits their apoptosis
What methods are used to diagnose osteoporosis?
DEXA, QCT
Bone biopsis from iliac crest
Bone markers from serum or urine
What are some of the treatments for osteoporosis?
Anti-resorptive Agents: Oestrogen,SERM, Calcitonin, Biphosphonates
Anabolic agents (increase bone formation): PTH, Sclerostin neutralising Ab (Romosozumab)
What would be a course of treatment for osteoporosis?
- anabolic first for patients with high fracture risk
- sequential treatment with anti-resorptive agents
- weight bearing exercise and some diets
What is disuse osteoporosis?
Localised or gerneralised bone loss resulting from reduction of mechanical stress on bones
Bone loss most marked in lower body etc.
