Osteoporosis and Other Metabolic Bone Disorders Flashcards
What happens first in bone remodeling?
The osteoclasts secrete enzymes and acids that degrade bone. They then secrete messenger molecules that activate osteoblasts.
Osteoblasts secrete _______________.
osteoid
Where do osteocytes come from?
Osteoblasts
Osteoclasts are activated by the ligand ____________.
RANK
Osteoblasts are activated by the __________ pathway.
Wnt
Osteoporosis predisposes people to fragility fractures. What are those?
Fractures due to minor trauma
Osteoporosis is more severe than _____________.
osteopenia
In wedge fractures of the vertebra, the __________ side is narrower.
anterior (leading to kyphosis)
Once you’ve had one fragility fracture, your risk of having another is ______________.
fivefold
What is the most common critical period for bone resorption?
Menopause
What formula needs to be satisfied to mineralize bone?
[Ca] x [PO4] must be greater than 24
95% of all genetic rickets is _____________.
congenital hypophosphatemic rickets (resistant to vitamin D)
The pathognomonic radiologic finding for osteomalacia is _________________.
pseudofractures –lines of demineralization where arteries press against bone
What two things are thought to cause Paget’s disease?
- Genetic predisposition
- Paramyxovirus infection
________________ is usually the gene implicated in familial Paget’s.
SQSTM (sequestasome)
______________ ownership has been linked to Paget’s disease.
Dog
What symptoms are typical of Paget’s?
Bone pain
Fractures
Osteoarthritis
Bone deformity
Paget’s can cause ___________ by two ways.
deafness (the ways being ossification of the foramen through which the cochlear nerve exits and ossification of the ossicles)
Alkaline phosphatase is secreted by osteo-_________.
blasts
What are the radiologic signs of Paget’s disease?
“Blade of grass” lesions in long bones and punched-out lesions in flat bones
On pathologic slides, the bone of someone with Paget’s will display _______________.
disorganized trabeculae and expanded cortex
How might you hear osteoclasts histologically described?
Multinucleated giant cells
_______________ function as the mechanoreceptors in bone, increasing deposition of minerals when stress increases.
Osteocytes
Binding to ____________ stimulates bone resorption.
RANK
What densitometry scores correspond to osteopenia and osteoporosis?
Osteopenia: less than 1.0 SD below average
Osteoporosis: less than 2.5 SD below average
What doses of calcium and vitamin D are recommended in those with osteoporosis?
1,500 mg of calcium and 1,000 units of vitamin D
Bisphosphonates and SERMs are classified as ______________ agents.
anti-resorptive
What causes vitamin D-dependent Rickets types 1 and 2?
Type 1: defect of 1-alpha hydroxylase (type 1 = 1-alpha)
Type 2: defect of vitamin D receptor
Hypophosphatemic Rickets is also called _______________.
vitamin D resistant Rickets
What are the three phases of Paget’s disease?
- Osteoclast predominance (5 years; high N-telopeptides)
- Osteoblast predominance (10 years; alk phos elevated)
- Osteoclast predominance ( indefinite; high N-telopeptides)
The most frequent kind of osteoporosis fracture is __________.
spinal
The incidence of Paget’s disease went down, perhaps due to the introduction of the _________ vaccine.
measles
Those with ____________ also have cardiovascular features.
Paget’s
