21. Metabolic Bone Disease Flashcards
What are the differences between Trabecular and Cortical bone?
Trabecular (aka Cancellous bone) fulfills the METABOLIC function of bone. It stores ions, and is surrounded the cortical bone. It makes up 20% of the skeletal mass, and undergoes 80% of the remodeling of bone.
Cortical (aka Compact) bone fulfills the MECHANICAL and PROTECTIVE function of bone. It is 80-90% calcified, thus very hard. It makes up 80% of the skeletal mass, and undergoes 20% of the remodeling of bone.
P.S. Trabecular bone is more affected by osteoporosis because it undergoes most of the remodeling of bone.
What bone deformity would one see with Rickets?
Bowing of the long bones and Widening of the epiphyses.
How are the Calcium and Phosphate levels in Osteomalacia and Rickets?
They are BOTH low. Usually they’re inversely related, but in this case both are low.
When does most bone loss occur in osteoporosis?
50% of the bone a patient will ever lose will be lost in the first 7 years after menopause, so this is the time to treat.
What is osteoporosis?
A systemic skeletal disease characterized by low bone mass and MICROARCHITECTURAL deterioration of bone tissue, with a consequent increase in bone fragility and susceptibility to fracture. Hip fractures often occur first, or compression fractures of the spine.
What is the epidemiology and mortality of osteoporosis?
1 in 4 women will develop osteoporosis. There is a 20% mortality rate within one year of osteoporotic fracture. (hip)
What is the difference between Postmenopausal (Type I) and Senile (Type II) Osteoporosis?
Postmenopausal Osteoporosis (Type I) occurs mostly in FEMALES, ratio 6:1. Main loss is Trabecular bone. Main cause is Estrogen deficiency.
Senile Osteoporosis (Type II) occurs mostly in MALES, ratio 2:1. Loss is both Trabecular and Cortical bone. Main cause is age-related factors and Androgen deficiency.
What are the differences between T and Z score for a DXA scan?
T score: Standard deviations above or below the mean of young adults, AKA against people at PEAK bone mass. This is the score you WANT.
Z score: Standard deviations against age, gender, and race matched individuals. USELESS.
What are the T scores corresponding to Normal bone mass, Osteopenia, and Osteoporosis?
Normal = Greater than or equal to -1.0
Osteopenia = -1.0 to -2.5
Osteoporosis = less than or equal to -2.5
-or if they’ve ever had a fragility fracture with ANY T Score (severe)
What is FRAX?
An online risk calculator for fractures related to osteoporosis.
What is the best drug to use for Osteoporosis?
Forteo, which is a recombinant PTH agonist. It only stimulates the anabolic effects on bone.
What are the newer risks of Biphosphonates?
They can cause Osteonecrosis of the jaw. So if there is anything wrong with your teeth, you cannot go on Biphosphonates.
