Osteoporosis Flashcards
What is the role of osteoprogenitor cells?
Stem cell population, gives rise to osteoblasts
What is the function of osteoblasts?
Responsible for bone formation, covers surface of bones
what is the function of octeocytes?
maintain bones matrix via cell to cell communication
What is the function of osteoclasts
They reabsorb bone matrix via demineralization in response to mechanical stress and physiological demand
Describe bone mass at different ages
0-25 years = bone gain.
25-35 years = bone mass stable.
35+ = bone loss
What are some key features of osteoporosis?
Decreased size of osteons, thinning of trabeculae, enlargement of haversain and marrow spaces.
What are some risk factors for osteroporosis and the incidence in the population
Risk factors - Biological sex, life style, nutrition, medical conditions, drugs, previous fragility fracture. Affects 1 in 3 women and 1 in 12 men.
describe some of the lifestyle and nutritional risk factors.
Smoking, excess alcohol, sedentary and prolonged immobilisation.
Name some medical conditions that are risk factors for osteoporosis
Anorexia nervosa, rheumatoid arthritis, early menopause, hyperthyroidism and primary hypogonadism
Name some drugs that are risk factors for osteoporosis
Chronic corticosteroid use, excessive thyroid therapy, gonadotrophin releasing hormone agonists or antagonists, anticoagulants, anticonvulsants and chemotherapy
What are the factors that contribute to an osteoporotic fracture?
falls, bone strength, postural reflexes, soft tissue padding
Describe the features of type 1 osteoporosis
Post menopausal. Mainly affects cancellous bone. Vertebral and distal radius fractures common. Related to loss of oestrogen. F:M = 6:1
Describe features related to type two osteoporosis
Age related in 75+/ Affects cancellous and cortical bone, related to poor calcium absorption, hip and pelvic fractures common, F:M = 2:1
What is disuse osteoporosis?
Conditions resulting in prolonged immobilisation typically neurological or muscle disease.
What is a fragility fracture?
A fall from standing height or less, not something that would occur in a healthy skeleton
What are the common sites for an osteoporotic fracture?
Proximal humerus, distal radius, spine, femoral neck and vertebral body
What are some of the investigations for osteoporosis?
Blood tests, FBC, serum biochemistry, bone profile.
Thyroid function tests, testosterone and gonadotrophin levels in med.
X-ray of lumbar and thoracic spine.
Bone mineral density measurement
What is Dexa?
Two low dose x-rays with two distinct energy peaks. Subtracting one from the other gives patient’s bone mineral density (BDM).
What are the two dexa scores?
T score - comparison with young adult of same gender.
Z score - Comparison with patients BMD with data from same age/sex/size.
What are the treatments for osteoprosis?
Bisphosphonates (disrupt activity of osteoclasts but side effects of oesophagitis and mandibular necrosis.) Anabolic agents, calcium supplements, hormone replacement therapy (risk of breast cancer) and increase exercise