Bone & Joint Infections

Question 1

What is the typical cause of paediatric osteomyelitis?

Answer 1

Hematogenous spread, mostly due to Staphylococcus aureus (90%).

Question 2

Which organisms commonly cause neonatal osteomyelitis?

Answer 2

Staphylococcus aureus, Group B streptococci, Gram-negative organisms, Haemophilus influenzae.

Question 3

What is the duration that defines acute osteomyelitis?

Answer 3

Infection within the first 6 weeks following inoculation.

Question 4

What is the duration that defines chronic osteomyelitis?

Answer 4

Infection lasting more than 6 weeks.

Question 5

What is the primary diagnostic method for bone or joint infection?

Answer 5

Bone aspiration.

Question 6

What imaging modality is best for early detection of osteomyelitis?

Answer 6

MRI.

Question 7

What radiographic features are common in osteomyelitis?

Answer 7

Sequestrum, involucrum, periosteal elevation/reaction, cloaca.

Question 8

What laboratory investigations are used in diagnosing osteomyelitis?

Answer 8

FBC, CRP, ESR.

Question 9

What is the role of CRP and ESR in osteomyelitis?

Answer 9

Baseline and follow-up to monitor treatment effectiveness.

Question 10

When should antibiotics be started in suspected bone infection?

Answer 10

Immediately after aspiration.

Question 11

What is the most common pathogen in adult septic arthritis?

Answer 11

Staphylococcus aureus (44%).

Question 12

What joint is most commonly affected in adult septic arthritis?

Answer 12

Knee (40–50%).

Question 13

What is the Cierny-Mader Classification type I?

Answer 13

Medullary infection only; no need for bone stabilization.

Question 14

What is Cierny-Mader type II?

Answer 14

Superficial cortex infection; no reconstruction needed.

Question 15

What is Cierny-Mader type III?

Answer 15

Localized infection requiring full-thickness cortical resection.

Question 16

What is Cierny-Mader type IV?

Answer 16

Diffuse cortical and endosteal infection; requires bone reconstruction.

Question 17

What surgical steps are taken in severe osteomyelitis?

Answer 17

Extensive debridement, soft tissue coverage, stabilization.

Question 18

What minimum antibiotic duration is required in adult osteomyelitis?

Answer 18

At least 6 weeks of IV antibiotics.

Question 19

What signs suggest paediatric osteomyelitis?

Answer 19

Fever, swelling, pain, refusal to walk.

Question 20

What is the next step if bone aspiration is negative?

Answer 20

Do bone scan.

Question 21

What defines paediatric septic arthritis?

Answer 21

Infection inside the joint from hematogenous spread or adjacent osteomyelitis.

Question 22

Which paediatric joints are most susceptible to septic arthritis?

Answer 22

Hip and shoulder.

Question 23

What is the first-line imaging in osteomyelitis diagnosis?

Answer 23

Plain radiograph.

Question 24

What does sequestrum indicate?

Answer 24

Dead bone tissue, seen as radiolucent/lytic lesion.

Question 25

What is involucrum?

Answer 25

New sclerotic bone formed around dead tissue.

Question 26

What causes periosteal elevation in osteomyelitis?

Answer 26

Spread of abscess to subperiosteal space.

Question 27

What is a cloaca in bone infection?

Answer 27

Opening in involucrum for pus drainage.

Question 28

What should be done if pus is aspirated?

Answer 28

Irrigation and debridement surgery, start antibiotics.

Question 29

What is done if no pus is aspirated?

Answer 29

Antibiotic treatment only.

Question 30

What type of needle is used for bone aspiration?

Answer 30

Large-bore 16- or 18-gauge spinal needle.

Question 31

Where should aspiration be performed?

Answer 31

Sites of maximal swelling and tenderness.

Question 32

What is the infection route in adult OM?

Answer 32

Often hematogenous or exogenous.

Question 33

What are common sites of infection in IV drug abusers?

Answer 33

Sternoclavicular, sacroiliac, and manubriosternal joints.

Question 34

What bacteria is common in IV drug abuse OM?

Answer 34

Pseudomonas aeruginosa.

Question 35

What is the minimum duration of antibiotics in adult septic arthritis?

Answer 35

IV for at least 2 weeks.

Question 36

What joints are commonly involved in adult septic arthritis?

Answer 36

Knee, hip, shoulder, ankle.

Question 37

What is the consequence of untreated septic arthritis?

Answer 37

Rapid destruction of articular surfaces.

Question 38

What is the diagnostic workup for septic arthritis?

Answer 38

Joint aspiration, Gram stain, culture & sensitivity.

Question 39

Why is the metaphysis prone to infection in children?

Answer 39

Low pH and pO2 favor abscess formation.

Question 40

What separates metaphysis and epiphysis in children?

Answer 40

Epiphyseal (growth) plate.

Question 41

What causes pseudo-paralysis in septic arthritis?

Answer 41

Pain and refusal to move joint.

Question 42

What is the first lab test in a child with suspected joint infection?

Answer 42

ESR, CBC, plain radiograph.

Question 43

What if initial imaging is negative?

Answer 43

Observation

Question 44

How soon do radiographic changes appear in OM?

Answer 44

10–14 days.

Question 45

When are sequestrum and involucrum visible?

Answer 45

6 weeks or more.

Question 46

What imaging is used for early OM if X-ray is negative?

Answer 46

MRI.

Question 47

What is the purpose of joint washout in septic arthritis?

Answer 47

Remove pus and infected material.

Question 48

What is the difference in ESR use between OM and septic arthritis?

Answer 48

Used in OM, not needed in acute septic arthritis.

Question 49

What is the treatment if bone is exposed but stable?

Answer 49

Bone flap and soft tissue coverage.

Question 50

What is the treatment for localized OM without surgery?

Answer 50

IV antibiotics.

Question 51

What is a hallmark symptom of paediatric bone infection?

Answer 51

Persistent crying.