osteomyelitis

Question 1

definition

Answer 1

inflammation of the bone and the bone marrow almost always due to infective organisms

Question 2

which sites are commonly affected in children and adults

Answer 2

children : the long bones and very commonly the metaphysis of long bones (femur) due to that area being highly vascularised

adults: due to lack of growth plates and hence vascularisation, the vertebrae are very commonly affected

Question 3

organisms which cause OM

Answer 3

we have pyogenic and non pyogenic (pus forming)
most common pyo: S.aureus
most common non pyo: M.tuberculosis

other common ones are salmonella (sickle cell disease)

Question 4

routes for entry

Answer 4

1. hematogenous spread (most common) like iv users and dental extraction
2. open fracture (direct exposure and periosteum is interrupted
   3.surgery
3. contiguous spread - diabetic foot ulcer

Question 5

how is the periosteum damaged?

Answer 5

by enzymes released by the bacteria themselves or by the immune system neutrophils etc which also degrade bone

Question 6

symptoms of osteomyelitis

Answer 6

acute - fever, pain at site, may not be able to use that joint properly

chronic - prolonged fevers, weight loss (chronic inflammation ) sinus tracts (pusu draining through skin ) , soft tissue damage

Question 7

most common organism

Answer 7

staph auerua and other coagulase negative staph (remeber aureus is +)

Question 8

rf

Answer 8

immunosupression
drug user
diabetes and peripheral vascular disease
having surgery
extremes of age
malnutrion
maliganny

Question 9

seuqetsreum

Answer 9

its where the necrotic bone is sealed off from the health bone

Question 10

investigations

Answer 10

1. bloods (inflammatory markers)
2. imaging - ct scans look for necrosis , x ray look for typical features but note if its acute it may not be present yet ) . MRI is the best for bone and soft tissue
3. samples of pus (can be unreliable from tracts)
4. bone biopsy
5. blood cultures

Question 11

tx

Answer 11

ab minimum 4-6 weeks empirical fluoxcacillin if allergic give macrolides like clindamycin

ifi mrsa give vanco or teicoplanin

surgery if you have sequestreum

Question 12

which imaging modality is the best

Answer 12

MRI - amazing for bone and soft tissue

Question 13

definitive

Answer 13

Definitive diagnosis - need a bone biopsy for pathology and culture.

Question 14

complications

Answer 14

1. SEPSIS
2. SEPTIC ARTHTTITS
3. sinus tracts abd fistulas
4. patholoigc fractures
5. in kids growth distrurbances

Question 15

why is mri better than ct and ray

Answer 15

cos it can detect earlier changes which may be seen in the others