Bone non-neoplastic diseases

Question 1

what are the non-neoplastic disorders found in bone?

Answer 1

1) congenital
2) osteoclasts dysfunction
3) osteonecrosis
4) metabolic bone diseases
5) infections
6) fractures
7) miscellaneous

Question 2

what are the congenital disorders of bones?

Answer 2

1) osteogenesis imperfecta 2) achondroplasia 3) osteopetrosis

Question 3

what is another name for osteogenesis imperfecta?

Answer 3

brittle bone disease (fragilitas ossium)

Question 4

what is osteogenesis imperfecta?

Answer 4

defective synthesis of type 1 collagen by mutations in alpha 1 and 2 chains of collagen

Question 5

what will you find in osteogenesis imperfecta?

Answer 5

a lot of fractures blue sclera deafness

Question 6

what is achondroplasia?

Answer 6

impared formation of long bones and of cartilage at growth plate

Question 7

where is the mutation in achondroplasia?

Answer 7

FGFR3

Question 8

is the mutation dominant or recessive?

Answer 8

dominant

Question 9

what is happening at the molecular level in achondroplasia?

Answer 9

overexpression of FGFR3 causes inhibition of cartilage synthesis in growth plate reducing the growth of long bones

Question 10

what are the clinical findings of achondroplasia?

Answer 10

short extremities poor endochondrial bone formation

Question 11

is the intramembranous bone affected in achondroplasia?

Answer 11

no

Question 12

what is another name for osteopetrosis?

Answer 12

marble bone disease

Question 13

what is osteopetrosis?

Answer 13

group of bone diseases that have decreased osteoclast function

Question 14

what will osteopetrosis show in a lab?

Answer 14

greatly increased bone resorption

Question 15

what characterizes the pathology of osteopetrosis?

Answer 15

• Bones becomes dense, thick • Marrow cavity replaced by bone • The thickened bones are brittle and fracture easily.

Question 16

what is the most common defect found in osteopetrosis?

Answer 16

carbonic anhydrase 2 mutation causing loss of acidic environment

Question 17

what are the 3 stages of Paget’s disease?

Answer 17

1. Osteolytic stage
2. Mixed osteolytic-osteoblastic stage
3. Osteosclerotic - thick, sclerotic bone that breaks easy

Question 18

what are the clinical findings in osteopetrosis?

Answer 18

• Pancytopenia
• Leukoerythroblastic blood (in histology)
• Extramedullary hematopoiesis = hepatosplenomegaly
• Cranial nerve compression = by narrowing of cranial foramina
• Hydrocephalus

Question 19

what are the clinical findings in paget’s disease?

Answer 19

• Bone pain
• Increasing hat size*
• Hearing loss:*
• Lion like facies
• Skeletal deformities* = tibial bowing
• Elevated alkaline phosphatase*
• Increased risk of osteogenic sarcoma*
• High output cardiac failure = due to AV connections in vascular bone

Question 20

what is another name for paget’s disease?

paget’s disease is characterized by episodes of?

Answer 20

osteitis deformans

Excessive and disordered bone resorption by osteoclasts followed by exuberant but disorganized bone formation

Question 21

pagets disease can involve 1 bone or many bones…how do you call these types of involvement?

what common bones are involved?

Answer 21

Monostotic: involving one bone

Polystotic : involving multiple bones.

pelvis>skul>femur

Question 22

what do you see in the osteolytic stage of paget’s disease?

Answer 22

osteoclastic resorption of bone predominates

Question 23

what do you see in the osteolytic and osteoblastic stage of paget’s disease?

Answer 23

Osteolytic and increased osteoblastic bone formation

formation of new bone: soft/weak and little mineralization

• the deposition is in mosaic formation (like tiles)
• look for increased alkaline phosphatase levels

Question 24

what is the treatment for paget’s disease?

Answer 24

calcitonin: inhibits osteoclast function
biphosphonates: induces apoptosis of osteoclasts

Question 25

what is osteonecrosis?

Answer 25

Ischemic infarction of bone & bone marrow.

Question 26

what causes ischemia leading to osteonecrosis?

Answer 26

• Vascular interruption (fracture like the femoral neck)
• Corticosteroids*
• Alcoholism
• Sickle cell disease or Caisson disease.

Question 27

what are the most common sites of osteonecrosis?

Answer 27

femoral head

scaphoid bone

Question 28

what is a Medullary infarct?

Answer 28

infarct that involves marrow and the cancellous bone

(clinically silent)

Question 29

what is a Subchondral infarct?

Answer 29

Wedge shaped area of necrosis with viable overlying articular cartilage leads to chronic pain

Question 30

what is caisson disease?

Answer 30

an air embolism that goes into the bone