Bone And Joint Infection

Question 1

Is acute or chronic septic arthritis pyogenic

Answer 1

Acute - hot swollen

Question 2

Is septic arthritis more commonly mono articular or poly articular

Answer 2

Mono

Question 3

Most common route for pathogens to reach joint in septic arthritis

Answer 3

Blood

Question 4

Routes for pathogens to enter joint

Answer 4

Local soft tissue infection
Diagnostic or therapeutic procedures
Penetrating trauma
Adjacent osteomyelitis
Haematogenous

Question 5

Most common organisms causing septic arthritis

Answer 5

Staphylococcus aureus

Question 6

Septic arthritis risk factors

Answer 6

Previous damage to joint
Untreated systemic infection
Condition effecting blood supply to the joint

Question 7

Joint most commonly effected by septic arthritis

Answer 7

Knee

Question 8

what does elevated ESR and CRP show

Answer 8

Ongoing inflammatory reaction

Question 9

How does synovial fluid appear on examination in septic arthritis

Answer 9

Turbid
Purulent
High leukocytes predominantly neutrophils
Glucose <25mg/dL - less than serum

Question 10

Main leukocyte in septic arthritis

Answer 10

Neutrophil

Question 11

Septic arthritis signs on radiology

Answer 11

Soft tissue swellings
Joint capsule distension
Erosion of articular surface

Question 12

What type of septic arthritis causes joint space narrowing, effusion, erosions, and cyst formation on XR

Answer 12

Mycobacteria infection

Question 13

Septic arthritis treatment

Answer 13

Drainage and washout every few days
Antibiotics

Question 14

Reactive arthritis

Answer 14

inflammatory arthritis that manifests several days to weeks after a gastrointestinal or genitourinary infection

Question 15

Presence of Which HLA increases reactive arthritis risk

Answer 15

HLA-B27

Question 16

Reactive arthritis symtoms

Answer 16

Eye inflammation
Lower back pain
Diarrhoea
Scaly skin patches on genitals
Swelling in knee heel of ball of foot
Flaky skin on foot sole
Sausage toes

Question 17

How does TB infection reach the sacroiliac joint

Answer 17

Travels down psoas major

Question 18

How does osteomyelitis spread

Answer 18

Haematogenous
From adjacent infected focus

Question 19

Osteomyelitis risk factors

Answer 19

Impaired immune system
Impaired local vascular supply - diabetes mellitus, venous stasis, radiation fibrosis, SCD

Question 20

Why is diabetes mellitus a risk factor for bacterial infections

Answer 20

Uncontrolled blood sugar feeds bacteria

Question 21

Radiation fibrosis

Answer 21

Scar tissue that develops as a result of damage from radiotherapy

Question 22

Osteomyelitis signs and symptoms

Answer 22

Decreased limb movement
Adjacent joint effusion
Local non specific pain
Elevated neutrophil count
Elevated ESR

Question 23

Which type of osteomyelitis has rapid onset and which has insidious onset over 1-3 months

Answer 23

Rapid - Haematogenous long bone
Insidious - Haematogenous vertebral and chronic

Question 24

Brodies abscess

Answer 24

Subacute osteomyelitis
Lesion with central lyric region and sclerotic margins

Question 25

Effects of chronic osteomyelitis

Answer 25

Local bone loss Persistent drainage through sinus Rare complications - squamous cell carcinoma, amyloidosis

Question 26

Osteomyelitis investigations

Answer 26

MRI Bone scintigraphy Bone biopsy Blood culture Neutrophil count Radiography

Question 27

What imaging modality is used when suspicious of multi focal osteomyelitis

Answer 27

Bone scintigraphy

Question 28

How long is the lag between osteomyelitis infective course and changes being visible on XR

Answer 28

2 weeks

Question 29

Osteomyelitis management

Answer 29

Puncture and drainage of abscess Surgical debridement of sequestrum - dead bone Reconstruct bone - Allo/autograft 4-6wks antibiotics

Question 30

Sequestrum

Answer 30

piece of devascularised necrotic bone that becomes separated from the remainder of the bone in chronic osteomyelitis and acts as a nidus for ongoing infection

Question 31

Involucrum

Answer 31

Layer of new bone growth outside existing bone In osteomyelitis the reactive bone that forms around the necrotic sequestrum

Question 32

Where does prosthetic bone and joint infection occur

Answer 32

Ossetian tissues adjacent to prosthesis - bone cement interface, bone contiguous with prosthesis

Question 33

Causes of prosthetic bone and joint infections

Answer 33

Local inoculation in surgery Post op spread from surgical wound infection Haematogenous spread

Question 34

How are risks of prosthetic bone and joint infection decreased

Answer 34

Prophylactic antibiotics given before surgery to Treat any minor infections Wound packed with cement beads impregnated with antibiotics

Question 35

Prosthetic bone and joint infection signs and symptoms

Answer 35

Gradual onset progressive joint pain Sinus development Incr ESR incr neutrophil count Prosthesis movement

Question 36

Prosthetic bone and joint infection on x ray

Answer 36

Lucencies at bone cement interface Changes in component position Cement fractures Periosteal reactions Gas in joint

Question 37

Prosthetic bone and joint infection management

Answer 37

Removal of prosthesis, antibiotics for 6 wks, re implantation of new prosthesis 4 wks after removal Resection arthropathy Suppressive long term antibiotics