12 Ortho/soft tissue Pathology

Question 1

what gene is mutated in achondroplasia? is it recessive or dominant?

Answer 1

1) FGFR3 gene.

2) Autosomal dominant

Question 2

what does the FGFR gene mutation do to cause the bone to do?

Answer 2

it inhibits cartilage proliferation at the growth plates therefore preventing elongation

Question 3

Which disease is caused by mutations in the gene coding for collagen type 1?

Answer 3

osteogenesis imperfecta.

Question 4

what are some of the characteristics for osteogenesis imperfecta? (3)

Answer 4

blue sclera
brittle bones
bad teeth

Question 5

what are the two different forms of osteomylitis?

Answer 5

pyogenic
granulomatous
(these are divided by their histology)

Question 6

what generally causes pyogenic osteomyelitis in 1) adults, 2) neonates, and 3) sickle cell patients?

Answer 6

1) staph aureus in adults
2) Group B strep and HIB in neonates
3) Salmonella in sickle cell

Question 7

what are the two most common types of osteoporosis?

Answer 7

Post menopausal

Senile

Question 8

what causes rickets?

Answer 8

A defect in bone mineralization due to vitamin D deficiency

Question 9

what is the difference between rickets and osteomalacia?

Answer 9

rickets in children (distorted bones) osteomalacia in adults (weaker bones but not generally deformed)

Question 10

T/F Hyperparathyroidism and chronic renal disease can result in osteoporosis?

Answer 10

True, secondary osteoporosis.

Question 11

why does chronic renal disease result in osteoporosis?

Answer 11

The kidney is messed up and doesn’t secrete as much Phosphate. This results in increased levels of PTH in the blood b/c it wants to get rid of phosphate. (increased PTH) beyond normal results in more CA+ in the blood by breaking down bone.

Question 12

where do bone calluses form?

Answer 12

often from a bone fracture

Question 13

what causes pagets disease? what is the most severe outcome of pagets disease?

Answer 13

Paramyxovirus infection. Pagets disease can transform into osteosarcoma in a few patients resulting in death.

Question 14

what are the 3 phases of pagets disease? what is the overall result the bone that is formed?

Answer 14

1) initial osteolytic, followed by mixed lytic/blastic, lastly osteosclerotic
2) It ends up forming a mosiac pattern of weakened lamellar bone.

Question 15

T/F Fibrous dysplasia shows woven bone with osteoblastic rimming?

Answer 15

False, there is no osteoblastic rimming here.

Question 16

which diseases cause osteoblastic rimming?

Answer 16

1) osteoblastoma

2) osteoid osteoma

Question 17

what disease is this describing: benign tumor like lesion of the bone characterized by localized developmental arrest?

Answer 17

Fibrous dysplasia

Question 18

what are the 3 forms of fibrous dysplasia?

Answer 18

1) monostatic 70% (affects single bone)
2) Polystatic 27%
3) McCune albright syndrome (most important one)

Question 19

what 4 things describe McCune albright syndrome?

Answer 19

1) polystotic (many bones only on one side of body)
2) Cafe au-lait spots
3) endocrinopathies (ex: precocious puberty)
4) GNAS 1 mutation

Question 20

which disease shows a Chinese character like pattern in the woven bone?

Answer 20

fibrous dysplasia

Question 21

what causes osteoarthritis?

Answer 21

wear and tear from old age that stems from breakdown of cartilage over time with assocatiated cytokine production resulting in secondary changes in the bones.

Question 22

what are some secondary changes in the bones associated with osteoarthritis?

Answer 22

1) burnishing
2) subchondral cysts
3) osteophytes

Question 23

which joint is specifically not involved in RA?

Answer 23

Distal interphalangeal joint (DIP)

Question 24

which joints are usually involved in RA?

Answer 24

MCP and PIP joints. Characteristic: bilateral and involve multiple joints.

Question 25

which disease forms a pannus?

Answer 25

RA

Question 26

which disease forms necrotizing granulomas in the joints?

Answer 26

RA

Question 27

What is rheumatoid factor?

Answer 27

An IgM directed against the Fc portion of IgG

Question 28

what causes gout?

Answer 28

too much monosodium urate.

Question 29

what are some characteristics of gout crystals?

Answer 29

1) neg. birefringent (yellow=parallel)

2) large spicules