1 - Biochemical Disorders of Bone Flashcards
(25 cards)
What is osteoporosis?
A quantitative defect of bone characterised by reduced bone mineral density and increased porosity
According to WHO, what bone mineral density is classified as…
- Osteopenia (intermediate stage)
- Osteoporosis
Osteopenia: 1-2.5 standard deviations below mean peak value
Osteoporosis: >2.5 standard deviations below mean peak value
What are the two types of primary osteoporosis?
Type 1: Post-menopausal osteoporosis
Type 2: Osteoporosis of old age
What are the causes of secondary osteoporosis?
- Corticosteroid use
- Alcohol abuse
- Malnutrition
- Chronic disease
- Endocrine disorders
How is osteoporosis diagnosed?
DEXA scanning to measure bone mineral density
Although osteoporosis cannot be treated, what treatments can be used to slow progression?
- Exercise + good diet + sun exposure
- Calcium and vitamin D supplements
- Bisphosphonates
- Desunomab
Which intervention has shown the greatest efficacy for osteoporosis?
Bisphosphonates
In osteoporosis, serum bone chemistry is normal/abnormal
Normal
What is osteomalacia?
A qualitative defect of bone characterised by abnormal softening of the bone due to deficient osteoid mineralization
What is Rickett’s?
Osteomalacia in children resulting in deformities of the growing skeleton
What are the principal causes of osteomalacia?
- Calcium deficiency
- Vitamin D deficiency
- Phosphate deficiency
What may cause these deficiencies that lead to osteomalacia?
Malnutrition Malabsorption Lack of sunlight Hypophosphataemia Chronic kidney disease
Describe the following parameters of serum bone biochemistry in osteomalacia…
- Calcium
- Serum phosphate
- Serum alkaline phosphatase
- Calcium: low
- Serum phosphate: low
- Serum alkaline phosphatase: high
How is osteomalacia treated?
Vitamin D therapy
Calcium and phosphate supplementation
What does hyperparathyroidism involve?
Overactivity of the parathyroid glands with high levels of parathyroid hormone (PTH)
What are the causes of... - Primary - Secondary - Tertiary ... hyperparathyroidism?
- Primary: benign adenoma, hyperplasia, malignant neoplasm
- Secondary: physiological overproduction of PTH secondary to hypocalcaemia
- Tertiary: chronic secondary hyperparathyroidism which will not improve with biochemical correction
What does overproduction of PTH cause?
Hypercalcaemia
What are the symptoms of hypercalcaemia?
fatigue, depression, bone pain, myalgia, nausea, thirst, osteoporosis
What 2 lytic lesions can be caused by hyperparathyroidism?
- Brown tumours
- Osteitis fibrosa cystica
What is renal dystrophy?
The typical bone changes seen in chronic kidney disease
These include osteomalacia, sclerosis of bone and calcification of soft tissues
What is Paget’s disease?
A chronic bone disorder resulting in thickened, brittle and mis-shapen bones
Which bones are commonly affected by Paget’s disease?
Pelvis
Femur
Skull
Tibia
Which bones are commonly affected by Paget’s disease?
Pelvis
Femur
Skull
Tibia
Which bones are commonly affected by Paget’s disease?
Pelvis
Femur
Skull
Tibia
