MSK-infection Flashcards

1
Q

How long are Rgx normal in OM?

A

7-10 d

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2
Q

I say this, you say that: OM Spine

A

IV drug user

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3
Q

I say this, you say that: OM Spine + kyphosis

A

Tb (gibbus deformity)

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4
Q

I say this, you say that: OM UL SI joint

A

IV drug user

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5
Q

I say this, you say that: psoas m abscess

A

Tb

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6
Q

Is OM more common in adults or peds?

A

Peds

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7
Q

Is septic arthritis MC in adults or peds?

A

Adults

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8
Q

sequestrum

A

necrotic bone surr by granulation tissue

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9
Q

involucrum

A

thick sheath of periosteal bone around sequestrum

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10
Q

cloaca

A

defect in periosteum covering

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11
Q

sinus tract

A

channel from bone to skin (lined w/ granulation tissue)

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12
Q

chronic OM-definition, most spec sign

A
  • OM > 6wks

- sequestrum = most specific sgx active chronic OM

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13
Q

In setting of OM, who’s at risk for SCC?

A

draining sinus tract

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14
Q

How do you know if OM is healed?

A

Return of normal fatty marrow

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15
Q

acute bacterial osteomyelitis-3 categories

A

1) hematogenous (MC in child)
2) continuous
3) direct inoculation

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16
Q

Hematogenous OM has a predilection for…

A

metaphysis long bones

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17
Q

changes of bone <18 mo old ISO infection, cancer

A

vessels metaph –> epiph atrophy –> GP stops spread (can still occ)

  • “septic tank” in metaph
  • GP fuse –> septic tank resolves
18
Q

bone vessels infant vs child

A
  • < 1 mo-transphyseal

- <18 mo- metaphyseal

19
Q

OM <1 mo old, < 18 mo old, 2-16 yo

A
  • multi-centric, joint inv+, bone scan (-) 75%
  • epiphyseal
  • metaphyseal
20
Q

most sens & spec signs/sequences in OM

A

next to ulcer, cellulitis

  • sens-STIR
  • spec-T1 (-)
21
Q

ghost sign

A

indicative of neuro-osteoarthropathy with superimposed osteomyelitis.

refers to poor definition of the margins of a bone on T1-weighted images, which become clear after contrast administration.

22
Q

MC orgm of spinal OM/discitis

A

Staph aureus (IV drug user)

23
Q

phases spinal OM/discitis

A

VB –> disc –> adj VB

24
Q

spinal OM/discitis-imaging early vs late

A
  • early
    • rgx: (-)
    • MRI: paraspinal/epidural inflamm. T2+ disc & enh
  • late
    • rgx: irregular EP destruction, narrowing
    • MRI: T1-, T2+, enh
25
Q

MCC adult spinal OM/discitis

A

-surgery, procedure, systemic inf

26
Q

MCC pediatric spinal OM/discitis

A

hematogenous

27
Q

Labs spinal OM/discitis

A

ESR, CRP 80%

28
Q

best NM scan for spinal OM/discitis?

A

gallium (not wbc bone scan)

29
Q

who gets isolated discitis? classic hx?

A
  • pediatric: direct blood supply to disc

- classic hx: <4 yo w/ URI

30
Q

how many people with Tb have MSK involvement?

A

5% (spine=MC)

31
Q

Pott disease-what, app, BWs

A

Tb of spine

  • disc spared (until late)
  • multi-level skip involvement
  • BWs: “large paraspinal abscess, Ca psoas pabscess, gibus deformity”
32
Q

Gibbus deformity

A

focal kyphosis in Pott dx

33
Q

Pott disease mimics

A

brucellosis (can have disc preservation)

34
Q

Tb dactylics (spina ventosa)-what, where, who, img

A
  • short tubular bones of hands/feet in kids
  • smoldering infection w/o periosteal rxn
  • diaphyseal expansile lesion + ST swelling, no periosteal rxn
35
Q

rice bodies

A

sloughed, infarcted synovium w/ end stage RA, Tb of joints

36
Q

septic arthritis-where, who, img

A
  • large joints (abundant metaphysical bs)
  • IV drug users: SI joint, sternoclavicular joint
  • RFs: immsupp (old, AIDS), fucked up joints (RA), hardware (prosthetic joints)
  • img: JE (must be present) , synovial enh
37
Q

how fast do you need to act w/ septic arthritis?

A

destroys joint in 48 hrs

38
Q

pseudoarthrogram sign

A

air in joint excludes joint effusion

39
Q

necrotizing fasciitis-who, MCC, app

A
  • HIV, tx, DM, EtOH
  • polymicrobial –> GAS
  • fascial enh +/- gas (minority)
40
Q

Nec fasc of scrotum

A

Fournier Gangrene

41
Q

mc loc OM of foot

A
  • metatarsals
  • phalanges
  • calcaneus