Bone abnormalities Flashcards
What are the functions of bone?
Haematopoiesis
Metabolic tissue (mineral buffer, repair damage, quality of bone)
Protective, supportive,
load bearing
If a normal bone is put under excessive force, what would happen?
Fracture
If a weak bone was put under normal force, what would happen?
Fracture
If a normal bone was put under normal force, what would happen?
Nothing! haha (no fracture
What blood tests can be performed to assess bone structure?
alkaline phosphatase! (also used in liver) albumin
calcium, phosphate!
vitamin D, parathyroid hormone
U&Es (kidney disease causes abnormal mineral regulation
FBCs
What imaging can be done to assess bone structure?
Plain X-ray
Radionuclide scans CT / MRI / ultrasound
Apart from blood tests and imaging, what other methods are there to assess bone structure?
Bone biposy and bone density (DEXA scan)
What is a DEXA scan?
Dual Energy X-Ray Absorptiometry (Block 4 week 2 CBL case)
What are the two kind of problems you can get with bone abnormalities?
Quantity of bone:
Too little - osteoporosis
Too much - osteopetrosis
Quality of bone:
Defective - rickets, osteomalacia and hyperparathyroidism
Change in structure - osteogenesis imperfecta and paget;s disease
How does parathyroid hormone (PTH) link to calcium levels and thus bone density.
Parathyroid glands secrete PTH. PTH regulates the level of calcium in the body. Calcium is needed to make bone.
What is osteoporosis?
A complex skeletal disease characterised by low bone density and micro-archeitectural defects in bone tissue, resulting in increased bone fragility and susceptibility to fracture.
What bones are most commonly fractured?
Vertebrae, femur and wrist
What wider implications can osteoporosis have?
Future fractures Quality of life Pain Long term admission Mortality
When is peak bone mass usually received?
around 30 years of age
What factors contribute to getting peak bone mass?
Nutrition, physical activity and genetic factors
How can menopause lead to osteoporosis?
Decreased serum oestrogen, increased IL-6/1, TNF levels, increased expression of RANK and RANKL, increased osteoclast activity
How can ageing lead to osteoporosis?
Decreased replicator activity of osteoprogenitor cells, decreased synthetic activity of osteoblasts, reduced physical activity, decreased biologic activity of matrix bound growth factors
Name some risk factors of osteoporosis
Old age, female, ethnicity, family history, low BMI, nutrition, vit D and calcium deficiency, steroids, post-menopausal, excessive alcohol
In a DEXA scan, what does the T-score show?
T-score used to compare bone density of patient with that of the average of the people of that age.
T-score more than -1 - normal
less than -1 but above -2.5 is osteopenia
less than -2.5 is osteoporosis
What type of pharmacological treatments are available for osteoporosis?
Bisphosphonates
SERM
PTH
Denosumab
Name the first line treatment of Bisphosphonates for osteoporosis.
Alendronic acid
What is the MoA of bisphosphonates?
Slows the rate of bone remodelling
Name a SERM used for osteoporosis and its moa.
Raloxifene - moxed antagonist and agonist function (tissue specific)
What are the side effects of SERMs?
Hot flushes, DVT and stroke