Infection

Question 1

What periosteal reaction is present?
What is the differential diagnosis?

Answer 1

Laminated periosteal reaction (aggressive)

1. Osteomyelitis
2. Ewing sarcoma
3. Osteosarcoma
4. Lymphoma

diaphyseal lesion in immature skeleton

Question 2

What pattern of destruction is present?
What are the top three differential diagnoses?

Answer 2

Permeative lytic (aggressive)

1. Osteomyelitis
2. Ewing sarcoma (diaphysis)
3. Osteosarcoma (metaphysis)

immature skeleton

Question 3

What are the present soft tissue findings?

Answer 3

• Soft tissue emphysema
• Sequestrum
• Swelling

osteomyelitis

Question 4

7-year-old male with leg pain, swelling, and a fever has normal x-rays.
This is a T1 fat suppression MRI with contrast.
What is the diagnosis?

Answer 4

Osteomyelitis

medullary cavity infection with cloaca

Question 5

3-year-old male presents with leg pain and swelling.
Which leg is the problematic one?

Answer 5

Left leg

R marker in corner

“dirty fat” takes on water density

Question 6

3-year-old male presents with leg pain and swelling. He is radiographed several days into his symptoms.
What radiographic infectious terms are present?

Answer 6

• Sequestrum
• Involucrum
• Cloaca

osteomyelitis

permeative lytic destruction (aggressive)

Question 7

Patient presents with insidious onset pain.
What is a three item differential?
What follow-up imaging is necessary?

Answer 7

• Brodie abscess (especially if recent infection or fever)
• Osteoblastoma (>2cm)
• Aneurysmal bone cyst

MRI with contrast

geographic lytic lesion in metaphysis with acute pain

Question 8

Patient presents with insidious onset pain.
What is the most likely diagnosis?

Answer 8

Brodie abscess

pus pocket with well defined margins of sclerotic border

Question 9

11-year-old male presents with chronic leg pain.
What radiographic finding suggests chronic osteomyelitis?
What is the differential diagnosis with this finding?

Answer 9

Solid wavy periosteal bone formation
Paget sarcoma

Question 10

12-year-old male presents with chronic leg pain.
What is the diagnosis?

Answer 10

Chronic osteomyelitis

DDx: Paget sarcoma

note solid wavy periosteal bone and cloaca

Question 11

What radiographic sign is present?
What does this mean by definition?

Answer 11

Waldenstrom’s sign: uneven hip joint space (one is increased) due to joint capsule swelling laterally displacing the femur

AVN of femoral capital epiphysis: LCP

Question 12

12-year-old female presents with hip pain that refers to the knee.
Based on the evidence of avascular necrosis in her femoral capital epiphysis, what is the diagnosis?

Answer 12

Legg-Calve-Perthes (LCP)

Waldenstrom sign present

Question 13

10-year-old female presents with a painful limp.
What is the diagnosis?

Answer 13

LCP

Legg-Calve-Perthes

sclerosis and flattening with epiphyseal fragmentation of femur (AVN)

Question 14

What findings are seen in the right femur?
What is the diagnosis?

Answer 14

Mushroom deformity, degenerative changes, superolateral displacement of femoral head
LCP

Question 15

Patient is radiographed 10 days after onset of forefoot pain.
Which structure is affected by avascular necrosis?

Answer 15

Third metatarsal head

Freiberg disease

Question 16

Patient is radiographed 19 days after onset of forefoot pain.
What is the diagnosis?
What are two underlying conditions which may result in this specific diagnosis?

Answer 16

Freiberg disease
Diabetes, alcoholism

osteochondrosis (AVN) of metatarsal head (3rd)

Question 17

What is the diagnosis?
What are the two most common etiologies?

Answer 17

Spondylodiscitis:

1. Staph aureus
2. Pseudomonas

disc and anterior vertebral endplate destruction

suppurative infection

Question 18

This is spondylodiscitis.
Why is an infection in this area particularly dangerous?

Answer 18

Increased spinal pressure leading to inflammation:

• meningitis
• encephalitis
• neural infection

Question 19

What findings are on this radiograph?
What is the diagnosis?

Answer 19

• Anterior vertebral body destruction
• Endplate loss
• Disc destruction

Spondylodiscitis

acute suppurative infection

Question 20

What is shown by the MRI with contrast?
What is the diagnosis?

Answer 20

Phlegmon
Spondylodiscitis

pus has more protein

Question 21

What is seen on these radiographs that suggests spondylodiscitis?

Answer 21

Paraspinal abscess on AP
Endplate erosive changes on lateral

cold abscess in psoas

Question 22

What is the radiographic sign?
What is the diagnosis?

Answer 22

Snowflake sign
Tuberculosis