Metabolic bone conditions Flashcards
Describe the blood serum results in osteoporosis
All normal
Describe the blood serum results in osteomalacia
Calcium low
Potassium low
Alkaline phosphatase high
PTH and vit D normal
Describe the blood serum results in Pagets
All normal except alkaline phosphatase
Describe the blood serum results in renal failure
Calcium low Potassium high Alkaline phosphatase either normal or high PTH high Vit D low
Describe the blood serum results in primary hyperparathyroidism
Calcium high Phosphate low Alkaline phosphatase either normal or high PTH high normal vit D
What is alkaline phosphatase produced from
Osteoblasts (bone) and the liver
At what rate is bone lost at the age of 40 onwards
0.7% a year
What speed is bone mass lost after menopause
2-9% a year
What 2 scores can bone mineral density expressed as
T or Z score
What is a T score
Number of standard deviations from the mean young (30y) same gender and ethnicity
What is a Z score
Number of standard deviations from mean aged, same gender and ethnicity
In terms of T score, when and how is a diagnosis of osteoporosis made
t score below 2.5
What does DEXA stand for
Dual energy X-ray absorptiometry
What is the prevalence of osteoporosis at
a) 50 and
b) 80
a) 2%
b) >25%
In terms of T score, when is a diagnosis of osteopenia made
between 1 and 2.4
What kind of bones are more susceptable to osteoporotic bone loss
High proportion of trabecular bone
Give 2 examples of bone susceptible to osteoporosis
Vertebral bodies
Femoral neck
Briefly describe/ define osteoporosis
Relative increase in resorption is not matched by formation. Bone is normally mineralised so there is less bone
Is loss evenly distributed in osteoporosis
No- trabeculae bone is more at risk
Why is trabeculae bone more at risk of osteoporosis
Because it has a greater surface area, and is in areas that respond to new stresses
How does osteoporotic bone differ to normal bone
Cortices and trabeculae are thinned
How would you treat an osteoporosis patient who is over 75 and has low trauma fracture
Bisphosphonate calcium and vit D
How would you treat an osteoporosis patient aged 50-75 and low trauma fracture
DEXA scan
Why are calcium supplements given to people with osteoporosis
Reduce negative calcium balance