Bone infection Flashcards

1
Q

the most common cause of septic arthritis

A

staphylococcus aureus
(MRSA)

haemolytic strep
pneumococcal streptococcus

children- Haemophilus, Kinsella

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2
Q

causes of septic native arthritis (bacterial)

A
  • direct haematogenous
  • direct inoculation (Trauma) (bite)
  • contiguous focus infection (intracapsular metaphysis- boney infection where the infection lies in the capsule of the joint) (diabetic foot)
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3
Q

acute purulent joint management

A
aspirate/drain
blood cultures
bacterial and target molecular assays
baseline CRP to monitor therapy
additional serology (looking for Lyme disease spread by sheep ticks/ Q fever arthritis)
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4
Q

viral and chronic arthritis

A
usually polyarthropathy due to systemic viral infection
parvovirus B19
seroconversion type illness
HIV
tropical arboviruses (chikungunya)
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5
Q

osteomyelitis definition

A

infection of the substance of the bone but encompasses many different scenarios.

haematogenous- long bone osteomyelitis in young children

infection following trauma

diabetic feet infection

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6
Q

causes of osteomyelitis

A

all: staph aureus

foreign body: a bone that’s normal resistance can become infected by low virulence commensals (Coagulase-negative staphylococcal) propionibacteria

nonsocosmial: pseudomonas, candida

ulcers: streptococci, anaerobes
sickle cell: salmonella, pneumococci

bites: Pasteurella, eikinella
children: Kingella, s aureus, HiB, group B strep, strep pneumonia, haemolytic streptococci.

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7
Q

management of osteomyelitis

A

debridement
removal of implants
long course parenteral antibiotics >6 weeks

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8
Q

chronic osteomyelitis

A

the body cannot get rid of the dead bone
need to maintain the function of the limb
the ultimate outcome is a chronic retained infection and loss of function

can get a sequestrum which needs to be removed else infection will continue.

can be treated with bone graft, soft tissue flap, skin graft (plastics)

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9
Q

biofilms definition

A

known as ‘slime’
it’s not mucus or snot
thin films of host and bacterial materials where the organism can live and become quiescent and can continue to cause damage.

host and microbial community which makes abx less effective

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10
Q

why can treatment fail?

A

poor abx penetration
dead or devitalized tissue
poor vascular supply
bacteria in a quiescent state and presence of biofilm.

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11
Q

principles of abx

A
ideal regiment
effective penetration of biofilm
oral 
cheap
safe
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12
Q

rifampicin

A

never use on its own
always use in combination

good against G+ve to get into biofilms and kills organisms in the quiescence state

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13
Q

acute haematogenous osteomyelitis

A

*in children
soft tissue problem primarily
surgical intervention if failure to resopnd to abx / local abscess

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14
Q

acute haematogenous osteomyelitis

A

*in children
soft tissue problem primarily
surgical intervention if failure to respond to abx / local abscess

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15
Q

acute septic arthritis in children

adults

A

children: drained and open

adult: urgent removal of purulent material from joint space. prevent enzyme related articular cartilage damage
* needle aspiration
* arthroscopic washout
* open washout (big joint)

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16
Q

acute septic arthritis in children

adults

A

children: drained and open

adult: urgent removal of purulent material from joint space. prevent enzyme related articular cartilage damage
* needle aspiration
* arthroscopic washout
* open washout (big joint)

17
Q

early postoperative infection

A
<3 months (4-6 weeks)
acquired during implant of surgery
staph aureus
beta haemolytic strep
gram-negative
18
Q

delayed infection

A
3-24 months (1-24 months)
in surgery/post op
Coag-neg staph
G-ve
propionibacterium
19
Q

late infection

A
>24 months
prior infection elsewhere in the body 
haematogenous seeding
staph aureus
beta
20
Q

PJI investigations

A
FBC, PV/ESR, CRP
MRI?
PET?
alpha defins?
look at the slides boo