Infection

Question 1

Term for bone infection vs joint vs disc infection

Answer 1

Osteomyelitis (bone)
Septic arthritis (joint)
Spondylodiscitis (disc)

Question 2

Highest age incidence for infection?

Answer 2

2-12 years (immature immune system, more exposure to organisms)

Question 3

Most common bones to be infected?

Answer 3

Femur (m/c) >tibia > humerus >radius (excluding diabetic foot which is crazy common)

Question 4

Delay in radiographic findings from the initiation of infection? (appendicular & spine)

Answer 4

7-10 days in the appendicular skeleton
21 days in the spine

Question 5

Do children or adults present with more acute symptoms of infection, typically?

Answer 5

Children

Question 6

Most common organism for MSK infection?

Answer 6

Staph Aureus (90%)

Question 7

Symptoms of infantile infection?

Answer 7

infant unwilling to move affected bone due to pain, may find swelling in the region of infection, may be multi-focal

Question 8

Most common route of spread for osteomyelitis?

Answer 8

Hematogenous

Question 9

Osteomyelitis is often indistinguishable on x-ray from…

Answer 9

Malignant bone lesions

Question 10

A piece of necrotic bone separated from living bone

Answer 10

Sequestrum

Question 11

A thick layer of enveloping periosteal new bone around an infection

Answer 11

Involucrum

Question 12

opening through involucrum/cortex into the marrow from the soft tissue

Answer 12

Cloaca

Question 13

Infection from bone weeping out of the skin surface

Answer 13

Sinus tract

Question 14

Radiographic features of spondylodiscitis?

Answer 14

Early/rapid loss of disc height, ENDPLATE DESTRUCTION

Question 15

In children age 1-16, osteomyelitis tends to localize where?

Answer 15

Metaphysis
Due to slow blood flow in metaphyseal capillary beds and low pH and oxygen tension

Question 16

Chronic/subacute form of localized osteomyelitis, may look loke a benign tumor

Answer 16

Brodie Abscess

Question 17

Radiographic features of a Brodie abscess?

Answer 17

Lucent lesion, poorly OR well defined, a lot of surrounding sclerosis (the surrounding sclerosis is what makes it a Brodie abscess and not just regular osteomyelitis)

Question 18

May be mistaken radiographically and clinically for an osteoid osteoma?

Answer 18

Cortical Brodie abscess

Question 19

MC location for a Brodie abscess?

Answer 19

Tibia

Question 20

Which would be best to identify a sequestrum, CT or MRI?

Answer 20

CT

Question 21

Osteomyelitis complications?

Answer 21

Pathologic fractures
Growth disturbances (children)
Ankylosis (septic arthritis)
Malignant degeneration (squamous cell MC)
Septicemia

Question 22

Monoarticular inflammatory arthritis

Answer 22

Infection (septic arthritis) until proven otherwise

Question 23

MC sites for septic arthritis?

Answer 23

Hip & knee, diabetic foot

Question 24

What is Waldenström’s sign?

Answer 24

Increase medial hip joint space (11mm total, 2mm difference side to side)
Indicates intraarticular swelling in the hip of children

Question 25

How to dx a joint infection most definitively?

Answer 25

Clinical features, plus joint aspiration and culture. Culture is frequently negative even when infected.

Question 26

What is a fight bite injury?

Answer 26

Septic arthritis in the hand, typically the MCP joint, due to tooth penetrating knuckle when punching someone in the mouth