404 Osteoporosis Flashcards
Final common path in osteoclast development and activation
Activation of RANK by RANKL
WHO operational definition of osteoporosis
T score of - 2.5
Cytokine responsible for communication between osteoblast, other marrow cells and osteoclast
RANK ligand
Stimulates bone formation by increasing the activity of osteoclast and decrease RANKL secretion
Wnt signaling pathway
Recommended daily requirement of calcium
1000-1200 mg
Targets of serum 25OHD for optimal skeletal health
More than 75 nmol/L or 30 ng/ml
Important risk factor for osteoporosis and fractures
Vitamin D insufficiency
Mechanism estrogen deficiency leads to bone loss
- Activation of remodeling sites
2. Exaggeration of imbalance between bone formation and resoprtion
Most common estrogen-deficiency state
Cessation of ovarian function at time of menopause
How does estrogen play a role in bone cells
Estrogen can control rate of apoptosis. In estrogen deprivation, life span of osteoblast is decreased and osteoclast in increased
Comprises 80% of bone surface area
Trabecular bone
Which has a small surface area: trabecular or cortical bone
Cortical
In osteoporosis, where does fracture open occur earliest
Where trabecular bone contributes most to bone strength
Most common early skeletal consequence of estrogen deficiency
Vertebral fractures
Most common causes of medication induced osteoporosis
Glucocorticoids
Highly accurate x ray technique that is the standard for measuring bone density
DXA
Preferred site for measurement of bone mineral densitt
Hip
Alternative area to measure bone mineral density when spine or hip is not measurable
Wrist
At what age is bone mineral density testing recommend to all women
Age 65 for females
Age 70 for males
When is a patient on glucocorticoids advised BMD testing
Prednisone more than 5 mg per day or equivalent for more than 3 months
In presence of hypercalcemia, how to differentiate Hyperparathyroidism and hypercalcemia of malignancy
Get serum PTH. Hyperparathyroidism has elevated PTH while hypercalcemia of malignancy has low PTH and high PTHrp
Suggested by low urine calcium
Malnutrition and malabsorption
High urine calcium of how much points to hypercalciuria
Urine calcium more than 300 mg/24 hours
When does hypercalciuria occur
- Renal calcium leak
- Absorptive hypercalciuria which can be idiopathic or increased 1,24 OH2D in granulomatous disease
- Hematolofic malignancies associated with excessive bone turnover
