Acquired Bone Disorders Flashcards Preview

Rheum/Musculoskeletal/Derm Week 1 > Acquired Bone Disorders > Flashcards

Flashcards in Acquired Bone Disorders Deck (47):
1

What is osteoporosis?

a reduction in trabecular bone mass resulting in porous bone with an increased risk of fracture and increased marrow space (that fills with fat mostly)

2

What are the most common forms of osteoporosis?

senile and postmenopausal

3

How does menopause decrease bone mass?

-decreased serum estrogen
-increased IL-1, IL-6, and TNF levels
-increased expression of RANK, RANKL and increased osteoclast activity

4

How does aging decrease bone mass?

there is decreased replicative activity of osteoprogenitor cells, osteoblast activity, activity of matrix-bound growth factors, as well as reduced physical activity

5

What causes type 1 (postmenopausal) osteoporosis?

decreased osteoblastic activity

6

What causes type 2 (senile) osteoporosis?

increased osteoclastic activity

7

What is a very common fracture with osteoporosis?

proximal femoral fractures (high mortality in older adults). Note, a fall to the side increases the risk of hip fracture by about 6 times compared to falls in other directions

8

What is a common treatment for osteoporosis?

Bisphosphates (also good for Paget's disease)

9

How do bisphosphates work?

they bind to hydroxyoptite and inhibits osteoclast activity

10

AEs of bisphosphates?

1) corrosive esophagitis- take with water and remain upright for at least 30 minutes

2) osteonecrosis of the jaw

11

What is osteomyelitis?

infection (most often bacterial) of the bone, typically in children caused from direct inoculation (trauma), contiguous spread (cellulitis), or blood spread

12

How does osteomyelitis present?

bone pain with systemic signs of infection

13

How does chronic osteomyelitis appear on x-ray (this is the best imaging for chronic)?

lytic abscess (aka sequestrum) surrounded by sclerosis of bone (aka involurum)

14

How does acute osteomyelitis appear on MRI (this is the best imaging for acute)?

inflammation

15

T or F. Get blood cultures before treating osteomyelitis

will commonly see elevated CRP and ESR (but not specific)

16

What is the most common cause of osteomyelitis?

Staph aureus (90%)

17

What is the most common cause of osteomyelitis in sexually active young adults?

N. gonorrhoeae

18

What is the most common cause of osteomyelitis in sickle cell patients?

Salmonella (encapsulated)

19

What is the most common cause of osteomyelitis in diabetics or IVDUs?

Pseudomonas (or candida or staph aureus)

20

What is the most common cause of osteomyelitis of the spine (Pott's Disease)?

Mycobacterium TB (giant cells without necrosis)

21

What is the most common cause of osteomyelitis with prosthetic limbs/joints?

Staph epidermidis

22

What is the most common cause of osteomyelitis from dog and cat bites?

Pasteurella

23

What are a few common pathologies that raise ESR over 100mm/hr?

-Osteomyelitis (staph aureus mostly)
-temporal arteritis
-polymyalgia rheumatica

24

What is the common end pathway for any pathology that disrupts vascular supply to the femoral head?

avascular necrosis/osteonecrosis

25

What are some common causes of avascular necrosis/osteonecrosis?

-fracture/trauma
-decompression sickness (the bends)
-exo/endogenous corticosteroids
-SCD
-alcohol abuse
-pancreatitis
-storage diseases

PASS FDS`

26

What are some common causes of avascular necrosis/osteonecrosis in 4-10 yo boys?

legg calve-perthes disease (idiopathic)

27

What is Paget's disease? Presentation

typically localized imbalance (increased) of osteoclast and osteoblast function-thick bone (idiopathic, possibly viral). Can be widespread

Patients might present with hearing loss (due to narrowing of the auditory foramen), bow legs, kyphosis or increased hat size

28

What is a suspected genetic cause of Paget's disease?

chromosome 18 mutations

29

Paget's disease is the most common cause of what?

isolated elevated alkaline phosphatase in patients over 40 yo

30

Paget's disease carries an increased risk of what?

osteosarcoma, increased AV shunts (heart failure), long bone fracture

31

T or F. Serum Ca2+ and PTH are normal in Paget's disease

T.

32

What are the phases of Paget Disease?

1) lytic- osteoclasts predominate
2) mixed- neither predominate
3) sclerotic- osteoblasts predominate

leads to thick bones that fracture easily

33

Skulls can take on a ____ appearance in Paget's disease

cotton wool

34

What is Osteomalacia (adults)/rickets (kids)?

inadequate mineralization of osteoid leads to weak bones and fractures due to vitamin D deficiency leading to soft, bowing bones

35

How do osteomalacia/rickets present in labs?

-decreased vitD, serum Ca2+ and phosphate (PO4)
-increased PTH and alkaline phosphate (due to increased osteoblast activity which need an alkaline environment)

36

What stain can be sued to ID osteomalacia/rickets?

von Kossa stain: calcified tissue is black and they are covered by a layer of unmineralized osteoid (dark pink)

37

T or F. There is abundant osteoid in Osteomalacia/rickets but it is not mineralized

T. Causing the bone to be weak and increase risk of fracture

38

What causes primary hyperparathyroidism?

hyperplasia or tumor (adenoma) of the parathyroid gland

39

What causes secondary hyperparathyroidism?

prolonged states of hypocalcemia due to chronic renal failure with resulting hyper secretion of PTH

40

What does increased PTH cause?

it is detected by osteoBLasts which stimulate osteoclasts leading to unabated bone resorption causing cyst-like brown tumors within the bone

41

What do the cyst-like brown tumors consist of?

fibrous tissue and woven bone without matrix

42

Why do the tumors of hyperparathyroidism take on a brown appearance?

there is cyst formation within the bone making it prone to hemorrhage which then turns brown from residual hemosiderin

43

Labs with hyperparathryoidism?

hypercalcemia,
increased PTH and
x-ray changed consistent with osteopenia

secondayr will show decreased GFR

44

What is osteitis fibrosa cystica (von Recklinghausen disease of bone)?

rare progressive disease of hyperparathyroidism with triad of:
-increase bone cell activity
-peritrabecular fibrosis
-cystic brown tumors

not seen often

45

What is renal osteodystrophy?

collectively describes skeletal changes associated with chronic renal disease when the kidney cannot convert vitamin D to active form

46

What does renal osteodystrophy encompass?

-increased osteoclastic bone respiration mimicking osteitis fibrosis cystica
-delayed matrix mineralization (osteomalacia)
-osterosclerosis
-growth retardation
-osteoporosis

47

Pathology of renal osteodystrophy?

decreased vitD leads to reduced Ca2+ absorption by the intestine leading to hypocalcemia and increased PTH secretion leading to increased bone resorption