RADIOLOGY OF OSTEOMYELITIS

Question 1

pathophysiology?

key to success is?

Answer 1

involves both the cortex and medullary canal

rapid diagnosis

Question 2

steps to take to treat diabetic patient with infected foot ulcer, possible osteomyelitis?

*diagnostic gold standard for OM?

Answer 2

plain film radiographs and probe to bone test

MRI, if necessary, and then

bone biopsy

*bone biopsy

Question 3

how is OM classified?

Answer 3

presentation and routes

presentation

• acute
• subacute
• chronic

routes based

• hematogneous (blood infection)
• direct extension (soft tissue infection)
• direct inoculation (step on nail)

Question 4

generally a disease of growing bone occurring most commonly in infants and children

Answer 4

acute hematogenous OM

Question 5

clinical features of acute hematogenous OM and pathophysiology?

Answer 5

pain, swelling, erythemia

infection starts in the metaphysis and then spreads

Question 6

what are the ages of acute hematogenous OM onset?

Answer 6

infantile
juventile
adult

Question 7

vascular communication btwn the metaphysis and epiphysis and once it gets to the epiphyses it can spread into the joint cavity?

what age is affected by this acute hematogenous OM

Answer 7

infantile

Question 8

vascular channel closed off

lower risk of OM except at some joints like hip

what age is affected by this acute hematogenous OM

Answer 8

juvenile

Question 9

growth plate gone so metaphysis goes to epiphysis and septic arthritis occurs

usually rare in adults, less so than juveniles

we see in drug abusers, sickle cell and immunosuppressed

what age is affected by this acute hematogenous OM

Answer 9

adult

Question 10

when is acute hematologic OM increased?

Answer 10

infants and adults

Question 11

radiographic changes seen in acute hematologic?

Answer 11

reparative changes in bones occur about 10 days after onset

most common pedal site for acute HOM is calcaneus

lags behind progression of disease

Question 12

radiographically what happens to bone in acute hematologic OM?

Answer 12

periosteal
endosteal
cortical

Question 13

radiographically, 2-3 days changes in acute hematologic OM?

Answer 13

inflammatory ST swelling

Question 14

radiographically, 10-14 days changes in acute hematologic OM?

Answer 14

radiographic changes show up

• patchy internal lysis
• focal ostepenia
• periosteal new bone formation
• minmal cortical destruction/erosion

Question 15

most common pedal site for acute HOM?

Answer 15

calcaneus, presents with lytic changes

Question 16

T/F, radiographic findings lag behind clinical course/progression of disease?

Answer 16

T

Question 17

more likely occurring in an older population so less likely to present as a periosteal reaction as the periosteum is more tightly adhered but still happens, not as dramatic

Answer 17

direct extension OM, this moves from periosteal space to medullary space beginning as an infection

Question 18

what are the radiologic changes?

Answer 18

early osseous changes 10-14 days

• focal osteopenia
• loss of cortical lysis at the onset
• periosteal reaction is variable

Question 19

where is general OM mostly seen in the foot?

Answer 19

metatarsal and proximal phalanges

Question 20

common characteristics of General OM once periosteal reactions are observed?

when an osseous infection is observed what imaging is used to help diagnose and determine extent of infections?

Answer 20

no periosteal rxns in the tarsal bones
distal and intermediate phalanges are rare

MRI, marrow edema being present