Biochemistry Flashcards
What is a quantitative bone defect?
When there is sufficient bone quality, but not enough is present.
What is a qualitative bone defect?
When there is sufficient bone quantity, but it is not of the required quality.
What is osteoporosis?
A quantitative bone defect characterised by decreased density, and increased porosity.
Defined as being >2.5 standard deviations BELOW the young adult peak.
What is a consequence of osteoporosis?
Increased fracture risk.
May occur with minimal trauma.
What is osteopenia?
A bone mass density between 1-2.5 standard deviations BELOW the young adult peak.
Can bone density loss be normal?
Yes, it is lost physiologically with age.
Most noticeable in women following menopause (as no effects of oestrogen remains within the system).
How is osteoporosis diagnosed?
DEXA scan
Remember to compare BMD to that of a young adult of the same race and gender.
Can osteoporosis be cured?
No, the aim of treatment is to prevent progression, and minimise risk of fracture.
How can risk of fracture be reduced in those with osteoporosis?
Healthy diet
Good exposure to sunlight
Vitamin D supplements
Calcium supplements
Bisphosphonates
What is a potential side-effect of both HRT and raloxifene?
DVT
Aside from bisphosphonates, what may be used to treat osteoporosis?
Desunomab
Strontium
Zoledronic acid
HRT
Raloxifene
By which mechanism do bisphosphonates help in osteoporosis?
Reduces osteoclastic function.
This is the first-line form of treatment.
By which mechanism does desunomab help in osteoporosis?
Reduces osteoclast activity.
A form of monoclonal antibody.
What form of drug is zoledronic acid?
Bisphosphonate - this type is given once yearly.
What is osteomalacia?
A qualitative defect which results from abnormal bone softening.
The result of deficiencies in bone mineralisation.
What is osteomalacia called in children?
Rickett’s
What is thought to be responsible for osteomalacia/Rickett’s development?
Insufficient absorption of calcium, or a deficiency of vitamin D.
How does osteomalacia/Rickett’s present?
Bone pain
Soft bone deformities
Features of hypocalcaemia
What are features of hypocalcaemia?
Bone pain
Renal stones
Abdominal groans
Psychiatric moans
How does osteomalacia/Rickett’s impact blood tests?
Low calcium
Low phosphates
High ALP
How is osteomalacia/Rickett’s treated?
Vitamin D supps
Calcium supps
Phosphate supps
What is hyperparathyroidism?
Overactivity of the parathyroid glands.
Will lead to high PTH levels, high calcium, and normal/low phosphate levels.
What may cause primary hyperparathyroidism?
Benign adenoma
Hyperplasia
Malignancy
What may be responsible for secondary hyperparathyroidism?
A physiological overproduction of PTH
Vitamin D deficiency
Chronic kidney disease
How are very high calcium levels treated?
IV fluids
Bisphosphonates
Calcitonin
What is renal dystrophy?
Bone changes observed in those with chronic kidney disease.
How does chronic kidney disease affect bone?
There will be reduced phosphate excretion and inactivation of vitamin D, resulting in secondary hyperparathyroidism.
This produces osteomalacia, sclerosis of bone, and the calcification of soft tissues.
What is Paget’s disease?
A chronic bone disorder that produces thickened, mis-shapen, brittle bones.
It is the result of increased bone turnover.
Where does Paget’s disease commonly affect?
Pelvis
Skull
Femur
Tibia
Ear ossicles
How does Paget’s disease affect blood results?
Normal calcium
Normal phosphates
Raised ALP
How should Paget’s disease be treated?
Give bisphosphonates
Manage any pathological fractures with IM nails/plating. Some may need joint replacement.
What diagnosis is indicated by a normal calcium, normal phosphate, normal ALP and normal PTH levels?
Osteoporosis
Osteopetrosis
Low calcium, low phosphate, raised ALP, and raised PTH levels are indicative of which diagnosis?
Primary hyperparathyroidism
Reduced calcium, normal phosphate, normal PTH, and raised PTH levels are indicative of which diagnosis?
Chronic Kidney Disease
Secondary Hyperparathyroidism
Normal calcium, normal phosphate, raised ALP, and normal PTH levels are indicative of what?
Paget’s disease
