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Flashcards in Bone Infections Deck (22)
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1

What are the different categories of Osteomyelitis?

Hematogenous Direct Implantation Contiguous Infection of Prosthetic Device

2

Resulting from seeding of bone related to previous bacteremia

Hematogenous

3

Resulting from penetrating injury

Direct Implantation

4

Resulting from direct spread of bacteria from an overlying wound or pressure ulcer

Contiguous

5

Resulting from infection of prosthetic material implanted in bone, with spread of organism into the adjacent bone

Infection of Prosthetic Device

6

What type of osteomyelitis is most coming in children? Adults?

Children -- Hematogenous Adults -- Contiguous and Prosthetic

7

What is an example of contiguous osteomyelitis? 

Diabetic foot ulcer

8

What types of pathogens cause hematogenous osteomyelitis?

Staphylococcus aureus

Streptococcus sp.

Gram negatives

Mycobacterium tuberculosis

Salmonella sp. (in sickle cell patients)

9

What type of pathogens cause direct implantation osteomyelitis? 

Pseudomonas aeruginosa in nail injuries with sneakers 

10

What type of pathogens cause contiguous osteomyelitis? 

S. aureus 

Gram negatives

Streptococcus sp. 

Anaerobes

Candida sp. 

11

What type of pathogens cause prosthetic joint infections? 

Coagulase negative staphylococci 

S. aureus

Gram-negatives

Streptococcus sp. 

12

What are some general characteristics of osteomyelitis? 

Often causes chronic infections that are difficult to eradicate. 

Damge to periosteum may result in dead bone pieces (sequestrum) or new external bone formation (involucrum); localized abscesses may also occur (Brodie's abscesses) 

X-rays may be neg in early infections and are not very senstive to osteomyelitis; Bone/WBC scans or MRI imaging are more effective

Bacteria causing osteomyelitis can be obtained from bone biopsies or sometimes blood cultures. 

13

What is most effective for diagnosing osteomyelitis? 

Bone biopsy 

14

What may be the result of damage to the periosteum in osteomyelitis? 

Sequestrum (pieces of dead bone) 

Involucrum (new external bone formation)

Localized abscesses (Brodie's abscesses) 

15

Does it work to get cultures of open ulcers overlying contiguous osteomeylitis? 

No -- they are notroiously unreliable.

The bacteria in the bone underneath may be entirely different. 

16

What if bone biopsies can't be done or cultures come back negative? 

Empiric treatment will be needed 

17

What is unique about prosthetic osteomyelitis? 

Particularly difficult to treat 

Often need to remove prosthesis 

Biofilms may develop making infections even more difficult to treat

18

What are biofilms? 

Aggregations of microorganisms adherent to a surface, particularly a hard surface like bones or teeth or prosthetic material 

19

What is different between biofilm organisms and planktonic (suspended) organisms? 

The biochemistry and physiology 

Biofilm bacteria are likely to be more resistant to antibiotics than are planktonic bacteria 

20

What is the treatment for osteomyelitis? 

Long course antibiotics

Generally 6 wks of intravenous therapy 

Surgery may be needed to remove sequestra or prostheses 

21

Which antibiotic is useful in treating biofilm organisms? 

Rifampin 

22

When is antibiotic treatment only useful? 

When bone is covered by tissue -- otherwise new organisms can continuously invade the bone