R/O - Pathology of bone disorders Flashcards Preview

Year 2 Specialty Medicine > R/O - Pathology of bone disorders > Flashcards

Flashcards in R/O - Pathology of bone disorders Deck (30):
1

unmineralized bone is called:

osteoid

2

osteoblasts secrete what growth factors?

- IL-1
- RANKL (receptor activator of NFkB which combines with RANK receptor on osteoclasts

3

what cells live in howship lacunae?

osteoclasts

4

osteoclasts are derived from what lineage?

hematopoietic progenitor cells

5

what type of bone?

- normally present in fetal skeleton, growth plates, and processes where there is very rapid bone production
- almost always pathologic in adults

woven

6

what are the 4 types of lamellar bone?

- concentric
- interstitial
- inner circumferential
- outer circumferential

7

what are the 3 developmental disorders of bone pathology?

- achondroplasia
- osteogenesis imperfecta
- osteopetrosis

8

what is the pathology of achondroplasia?

- point mutation in gene encoding for FGFR3
- FGFR is persistently activated - inhibition of normal proliferation of chondrocytes at growth plates

9

what is the inheritance of achondroplasia?

AD

10

premature sealing of growth plates - diagnosis?

achondroplasia

11

what cell type is proliferating in the zone of proliferation?

chondrocytes

12

what is the pathology of osteogenesis imperfecta?

- abnormalities of type 1 collagen synthesis
- mutations in genes that code for a1 an a2 chains

13

what is the inheritance of osteogenesis imperfecta?

AD

14

what are the 4 main types of osteogenesis imperfecta?

- type I: increased fracture risk, not deforming
- type II: lethal, multiple fractures in utero
- type III / type IV: progressive deformity

15

what is the morphology seen in OI?

- decreased bone thickness because of sluggish periosteal bone formation
- reduced number of trabeculae
- abnormally thin trabeculae

16

osteopetrosis is due to defective activity of what cell type?

osteoclasts

17

what is the pathology of osteopetrosis?

- decreased osteoclastic bone resorption
- diffuse skeletal sclerosis

18

what is the inheritance of osteopetrosis?

- AR: malignant
- AD: benign (normal life span)

19

what is the clinical picture of osteopetrosis?

- increased incidence of fracture (more brittle)
- anemia
- thrombocytopenia
- increased susceptibility to infections (less marrow space)
- possible cranial nerve palsies

20

what parts of bone are thinned in osteroporosis?

cortex and trabeculae

21

what are the primary causes of osteoporosis?

- age
- menopause

22

what is the best imaging modality for osteoporosis? why?

DEXA - identifies quantitative loss of bone

23

how does estrogen increase bone formation?****

- increases collagen synthesis by osteoblasts
- prevents bone resporption by inhibiting osteoclast differentiation (osteoprotegerin)

24

how does decreased estrogen (menopause) lead to decreased bone density?****

regulation of osteoclast activity:

- increased secretion of IL-1, IL-6, TNF, leading to increased RANK which stimulates osteoclasts
- decreased levels of osteoprotegerin (OPG), which is protective of bone

25

how does glucocorticoid excess affect osteoclast metabolism?

increase in:

- osteoclast survival
- cancellous osteoclasts
- bone resorption

26

how does glucocorticoid excess affect osteocyte metabolism?

- increased apoptosis
- decreased canalicular circulation
- decreased bone quality

27

how does glucocorticoid excess affect osteoblast metabolism?

- decreased osteoblastogenesis
- increased apoptosis
- early and continual decrease in cancellous osteoblasts, synthetic ability, bone formation

28

- generalized pain
- fractures
-mottled areas of lucency ("pseudofractures")

osteomalacia

29

- skeletal deformities
- loss of rigidity
- bowing of the legs
- enlarged costochondral junctions
- pigeon breast deformity
- kyphosis
- frontal bossing

rickets

30

osteomalacia is characterized by:

abnormally high ratio of osteoid to mineralized bone