Bone Infections

Question 1

What are the different categories of Osteomyelitis?

Answer 1

Hematogenous Direct Implantation Contiguous Infection of Prosthetic Device

Question 2

Resulting from seeding of bone related to previous bacteremia

Answer 2

Hematogenous

Question 3

Resulting from penetrating injury

Answer 3

Direct Implantation

Question 4

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

Answer 4

Contiguous

Question 5

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

Answer 5

Infection of Prosthetic Device

Question 6

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

Answer 6

Children – Hematogenous Adults – Contiguous and Prosthetic

Question 7

What is an example of contiguous osteomyelitis?

Answer 7

Diabetic foot ulcer

Question 8

What types of pathogens cause hematogenous osteomyelitis?

Answer 8

Staphylococcus aureus

Streptococcus sp.

Gram negatives

Mycobacterium tuberculosis

Salmonella sp. (in sickle cell patients)

Question 9

What type of pathogens cause direct implantation osteomyelitis?

Answer 9

Pseudomonas aeruginosa in nail injuries with sneakers

Question 10

What type of pathogens cause contiguous osteomyelitis?

Answer 10

S. aureus

Gram negatives

Streptococcus sp.

Anaerobes

Candida sp.

Question 11

What type of pathogens cause prosthetic joint infections?

Answer 11

Coagulase negative staphylococci

S. aureus

Gram-negatives

Streptococcus sp.

Question 12

What are some general characteristics of osteomyelitis?

Answer 12

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.

Question 13

What is most effective for diagnosing osteomyelitis?

Answer 13

Bone biopsy

Question 14

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

Answer 14

Sequestrum (pieces of dead bone)

Involucrum (new external bone formation)

Localized abscesses (Brodie’s abscesses)

Question 15

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

Answer 15

No – they are notroiously unreliable.

The bacteria in the bone underneath may be entirely different.

Question 16

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

Answer 16

Empiric treatment will be needed

Question 17

What is unique about prosthetic osteomyelitis?

Answer 17

Particularly difficult to treat

Often need to remove prosthesis

Biofilms may develop making infections even more difficult to treat

Question 18

What are biofilms?

Answer 18

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

Question 19

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

Answer 19

The biochemistry and physiology

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

Question 20

What is the treatment for osteomyelitis?

Answer 20

Long course antibiotics

Generally 6 wks of intravenous therapy

Surgery may be needed to remove sequestra or prostheses

Question 21

Which antibiotic is useful in treating biofilm organisms?

Answer 21

Rifampin

Question 22

When is antibiotic treatment only useful?

Answer 22

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