Bone Infection

Question 1

What is Osteomyelitis

List 4 types

Answer 1

Bony inflammation almost always due to infection

1. Bacterial (most common) - pyogenic osteomyelitis.
2. Tuberculous osteomyelitis
3. Skeletal syphilis
4. Fungal osteomyelitis

Question 2

Most common age and gender in osteomyelitis

Answer 2

• Between ages 2 - 12 years (can affect any age)
• More common in males

Question 3

Most common organism in osteomyelitis?

First line antibiotic treatment?

Answer 3

Staphylococcus aureus

Flucloxacillin

Question 4

Location of osteomyelitis within bone varies with age (due to changing blood supply)

State the affected region of bone in neonates vs children vs adults

Answer 4

Neonates : metaphysis and / or epiphysis

Children : metaphysis

Adults : epiphyses and subchondral regions

Question 5

Acute osteomyelitis in childhood most commonly affects which bone (2)

Answer 5

femur, tibia

Question 6

List 3 x-ray features of acute osteomyelitis in childhood

Answer 6

1. Sequestration frequent
2. Periosteal elevation (with disruption of periosteal blood supply)
3. Small single / multiple osteolytic areas in metaphysis

Question 7

List 2 complications of acute osteomyelitis in adulthood

Answer 7

1. soft-tissue abscess
2. pathological fractures

Question 8

List 4 risk factors for acute osteomyelitis in adulthood

Answer 8

1. IV drug use
2. Previous trauma
3. Immunosuppressed state
4. Diabetes
5. joint involvement common

Question 9

Gold star imaging for acute osteomyelitis

Answer 9

MRI - most sensitive and specific, is able to identify soft-tissue/joint complications

Question 10

Spinal Discitis is also known as what?

What is this?

Answer 10

Infective spondylosis

Infection involving the intervertebral disc and adjacent vertebrae

Question 11

Most common age affected by spinal discitis

Answer 11

Equal distribution among ages

Question 12

Most common organism in spinal discitis

Incl 2 others

Answer 12

1. Staphylococcus aureus (most common)
2. Streptococus viridans (IVDU & immunocomprimised)
3. Gram negative organisms
4. Mycobacterium tuberculosis

Question 13

Which spinal level does discitis most commonly occur?

Answer 13

Can occur anywhere but is most common in lumbar levels

Question 14

Gold star imaging for spinal discitis

Answer 14

MRI - very high sensitivity and specificity

Also useful in ddx between pyogenic infection, TB/fungal infection or neoplasia

Question 15

What age group is most commonly affected by Tuberculosis osteomyelitis?

Answer 15

children< 5 years (rare in adults)

Question 16

Which bones are most commonly affected in TB osteomyelitis

Which specific location of bone is affected?

Answer 16

Bones (can be any):

• femur, tibia, small bones of hand + foot (most common)

Site within bone

• Metaphysis (typically) with transphyseal spread
• Epiphysis with spread to joint/ spread from adjacent affected joint

Question 17

What is the other name given to Pott Disease and what is this?

Answer 17

Tuberculous spondylitis - refers to vertebral body and intervertebral disc involvement with tuberculosis

Question 18

What spinal levels are most commonly affected in Potts disease

Which region of the vertebrae is affected

Answer 18

Spinal level:

• Upper lumbar + lower thoracic spine (L1 most common)
• Typically more than one vertebra affected

Region:

• Vertebral body (82%)
• With predilection for anterior part adjacent to superior / inferior endplate

Question 19

Gold star investigation for spinal discitis

Incl 3 features seen

Answer 19

MRI (CT with contrast is second)

Features:

• Irregularity of endplate and anterior vertebral bodies,
• Bone marrow oedema
• Well circumscribed fluid collections with well defined center margins