20. Osteopetrosis (marble bone disease) Flashcards Preview

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Flashcards in 20. Osteopetrosis (marble bone disease) Deck (17)
1

Osteopetrosis is also called

marble bone disease

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osteopetrosis ( marble bone disease ) - pathophysiology

Carbonic abhydrase ---> impair ability of osteoclast to generate acidic enviroment ( necessary for bone resorption ) --> thichkened, dense bones

3

thichkened, dense bones of osteopetrosis prone to

fractures

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osteopetrosis - clinical manidestation ( why )

1. pancytopenia ( bone fills marrow space )
2. extramedullary hematopoiesis ( bone fills marrow )
3. cranial nerve inmpingement and palsies ( narrowed foramina )
4. hydrocephalus ( narrowing of the foramen magnum )
5. bone fractures
6. renal tubular acidosis ( carbanhydr II mut )

5

foramen magnum?

the hole in the base of the skull through which the spinal cord passes

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osteopetrosis - nerve inpingementd and palsies can cause

vision and hearing impairment

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osteopetrosis - renal involvement

renal tubular acidosis ( carbanhydr II mut ) --> decreased tubular reabsorption fo HCO3- --> metabolic acidosis

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osteopetrosis - X-ray - appearance

bonr - in bone appearabce

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osteopetrosis - cranial nerve inmpingement and palsies due to

narrowed foramina

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osteopetrosis - hydrocephalus due to

narrowing of the foramen magnum

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treatment of osteopetrosis ( why)

Bone marrow transplant is potentially curative as osteoclasts derived from monocytes

12

• A patient has been told he has dense bones, yet he is frequently fracturing them. What might he have?

Osteopetrosis (marble bone disease)

13

• In osteopetrosis, bone ____ (resorption/breakdown) is impaired as a result of abnormal ____ (osteoblasts/osteoclasts).

Resorption; osteoclasts

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• In osteopetrosis, serum Ca2+ is ____ (high/normal/low), PO43- is ____ (high/normal/low), alkaline phosphatase is ____ (high/normal/low).

Normal, normal, normal

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• What hematologic complications may arise from osteopetrosis?

Anemia, thrombocytopenia, infection (secondary to leukopenia), increased extramedullary hematopoiesis

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What neurologic lesions may result from osteopetrosis? Why?

Cranial nerve palsies due to narrowed foramina in the skull

17

• A 12-year-old boy who frequently fractures his bones is diagnosed with osteopetrosis. How would a bone marrow transplant cure him?

Transplanting normal cells may cure him (osteopetrosis is due to defective osteoclasts, which are derived from bone marrow monocytes)

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