osteomyelitis

Question 1

what is it

Answer 1

bacterial or fungal infection of the bone being either acute or chronic

acute infection is caused by a single organism (usually)

chronic infection is polymicrobial (usually)

Question 2

what are the most common underlying pathogens in osteomyelitis

Answer 2

staph. Aureus

coagulase negative staphylococci

Question 3

T/F the incidence of osteomyelitis has decreased due to rising prevalence of risk factors such as diabetes and PVD

Answer 3

F

it has increased due to increase of T2DM and PVD

Question 4

what is the pathophysiology of osteomyelitis

Answer 4

1. seeding from hematogenous infection (commonly occurs in children) - spreads from adjacent soft tissues or joints
2. direct inoculation of infection into bone due to wound containing during trauma or surgery

Question 5

what are some risk factors of osteomyelitis

Answer 5

DM
PVD
malnutrition
immunosuppression
malignancy
old age
local factors ie vasculitis

Question 6

presentation of acute osteomyelitis

Answer 6

fever
pain
swelling
erythema of the affected site

Question 7

presentation of chronic infection

Answer 7

a long history of pain
persistently draining sinus tract wound and soft tissue damage

Question 8

ivx

Answer 8

definitive diagnosis = bone biopsy for pathology and culture

supportive diagnostic tests = inflammatory markers, imaging (x-ray, MRI, CT)

other = blood cultures / any other cultures

Question 9

mxm

Answer 9

antibiotics :

abx for minimum of 4-6 weeks , at least 12 usually but in chronic may need abx for 3-6 months

> empirical = fluclox + fusidic acid/rifampicin or vancomycin if MRSA is suspected

-if penicillin allergic then clindamycin

start IV and switch to oral abx when patient is stable and or 2 weeks post surgery

chronic : treatment is usually delayed until culture and sensitivity results have been obtained

surgical debridement :

mainly for chronic osteomyelitis

acute infections can be treated with extensive surgical cleaning early on together with antibiotics

Question 10

A 40-year old man presents to the emergency department with swelling and pain in his lower leg. He has a history of an open tibial fracture in a skiing accident 5 months ago. He has fever and chills since yesterday evening and has lost his appetite. His only medical history is surgical repair of his fracture.

On examination the area over the tibia looks erythematous and swollen and is tender to touch.

A series of blood tests are sent off and high dose empirical antibiotics are started intravenously. A provisional diagnosis of osteomyelitis is made.

Which of the following blood tests results might be the best indicator that treatment is working?

Answer 10

ESR