Bone Infections/Osteomyelitis

Question 1

What are the categories of osteomyelitis?

Answer 1

Hematogenous

Direct implantatio

Continguous

Infeciton of Prosthetic

Question 2

Hematogenous osteomyelitis

Answer 2

resulting from seeding of bone related to a previous bacteremia

Question 3

Direct Implantation leading to osteomyelitis?

Answer 3

resulting from a penetratin injury

Question 4

what is contiguous osteomyelitis

Answer 4

resulting ftom direct spread of bacteria from an overlying wound or pressure ulcer

Question 5

how can infection of prosthetic devide lead to osteomyelitis

Answer 5

resulting from infection of prosthetic material implanted in bone, with spread of oragnisms into the adjacent bone

Question 6

what is the difference between hematogenous and and contiguous osteomyelitis?

Answer 6

hematogenous is more common in children and is usually monomicrobial, whereas contiguous osteomyelitis (more common in adults) is often polymicrobial

Question 7

What bugs are associated with hematogenous osteomyelitis?

Answer 7

staph aureus, strep spp, gram negatives, mycobacterium tuberculosis, salmonella sp (in sickle cell)

Question 8

what bug is common with direct implantation osteomyelitis?

Answer 8

pseudomonas aeruginosa is common n nail injuries with sneakers, but other organisms can be implanted too

Question 9

what bugs are associated with sontiguous osteomyelitis?

Answer 9

S. aerues, gram negatives, streptococcus sp., anaerobes (usually smelly) candida

Question 10

what bugs are associated with prosthetic joint infections?

Answer 10

coagulase negative staphylococci (sticks to stuff well) , S. aureus, gram negatives, streptococcus sp. propionibacterium acnes

Question 11

what accounts for 70-90% of hematogenous osteomyelitis in children?

Answer 11

Staphylococcus aureus

Question 12

WHat bugs are more frequent in patients with UTIs or infections from IV drug use

Answer 12

gram negatives such as E coli, Pseudomonas, Kelbsiells, enterobacter

Question 13

1-3% of patients with TB will have bone infections. What are these usually through?

Answer 13

through the blood stream or from direct extension from a pulmonary focus (to ribs or vertebral bodies)

Question 14

what is another very common std that can infect bone?

Answer 14

syphillis can infect bone (in chronic or congenital cases)

Question 15

WHat bug has become a very important bug in shoulder replacement infections

Answer 15

Probionibacterium (cutibacterium) acnes has become a very important pathogen in shoulder replacements

Question 16

Can osteomyelitis become chronic or is it always acute?

Answer 16

• often cause chronic infections that are difficult to eradicate

Question 17

During osteomyelitis what does damage to the periosteum result in?

Answer 17

peices of dead bone (sequestrum) or new external bone formation (involucrum); localized absesses may also occur (Brodie’s absess)

Question 18

What is the most effective imaging to look for osteomyelitis?

Answer 18

Bone/WBC scans or MRIS are much more effective!

X-rays can be negative in early infection and infacat are not sensitive

***gold standard to treat is to do a biopsy to figure out what the bug is

Question 19

what is the gold standard to make sure you are correctly treating the osteomyelitis?

Answer 19

getting a bone biopsy. the bacteria causing osteomyelitis can be obtaines from bone biopsies or sometime from blood cultures

Question 20

Is a culture of an open ulcer overlying a contiguous osteomyelitis reliable?

Answer 20

NO! they re noticably unreliable. the bacteria in the bone underneath may be entirely different

Question 21

WHat do yo udo if a bone biopsy cannot be done? or all culture results are negative?

Answer 21

empiric treatment (30-40%)

Question 22

what type of osteomyelitiis is often difficult to treat and what does this result in?

Answer 22

infections of prosthetic material are paticularly difficult to treat; the prosthesis often needs to be removed o eradicate the infection :( amputation may need to be done

Question 23

What makes osteomyelitis MUCH more difficult to treat?

Answer 23

biofilm! they may develop on infected bone or particularly on prostheses, making the infections more difficult to treat

Question 24

What are biofilms?

Answer 24

• aggregationg of microorganisms adherent to a surface, particularly a har dsurface like bones or teeth or prosthetic materials
• the adherent microoragnisms are frequently embedded in a matrix that they produce-called slime or extracellular polymeric substance or glycocalyx
• biochem and physiology or biofilm organisms are different from those of planktonic (suspended) organisms
• biofilm bacteria are liekly to be more reisstant to antibiotics than are planktonic bacteria

**often S. aurues-often sticking via the glycocalyx which looks like tubes

Question 25

How do we treat osteomyelitis?

Answer 25

• long course of antibiotics; 6 weeks IV, sometimes months of oral antibiotics (particularly for prosthetic joint infections) -**Rifampin often used**
• surgery may be needed to remove sequestra or prostheses (in cases where antibiotics fail)
• antibiotic rifampin is particularly useful for biofilms!!! markedly improved the sucess in therapy of prosthetic joint infections (but only for stahylocci and only those that are suscetible to it)
• Antibotic treatment is only useful if the bone is covered by tissue-otherwise, new organisms can continously invade the bone

Question 26

what are the common cauative organisms for osteomyelitis?

Answer 26

staphylococci (most common) streptococci, gran negatives, anaerobes, mycobacteria, and fungi (candidia)

Question 27

When is fever seen during osteomyelitis?

Answer 27

it is seen in acute osteomyelitis, and rare in chronic