Bone Infection

Question 1

What does a ‘heterogenous’ disease mean?

Answer 1

Can be caused by lots of organisms and at lots of different sites!

Question 2

What does haematogenous mean?

Answer 2

Infection spreading via the blood stream, may be a primary focal point of Infection.

Question 3

What does contiguous focus spread mean?

Answer 3

Spread of Infection adjacent to bone - eg ulcers

Question 4

Stage 1 osteomyelitis is know as what?

Answer 4

Medullary - confined to medulla of bone often due to haematogenous.

Question 5

Stage II osteomyelitis is also known as and involves?

Answer 5

Superficial - necrosis is limited to the exposed surface.

Question 6

Stage III osteomyelitis is and causes?

Answer 6

Localised- full thickness cortical sequestration, needs debridement island of bone is left.

Question 7

Stage IV osteomyelitis?

Answer 7

Diffuse and extensive unstable bone.

Question 8

What are the most common symptoms of osteomyelitis?

Answer 8

Localised pain
Soft tissue swelling
Erythema
Nocturnal pain - waking with pain
Reduced movement 
Progressive pain

Question 9

Which symptoms are uncommon in osteomyelitis?

Answer 9

Systemic illness, such as fever and chills

Question 10

At least 60% of osteomyelitis is caused by what organism?

Answer 10

Staph Aureus

Question 11

Causative organisms in osteomyelitis (6)?

Answer 11

Staph, Strep, TB, Enterococci, gram neg and anaerobes.

Question 12

What % of blood cultures are positive in osteomyelitis?

Answer 12

~50%

Question 13

Gold standard for diagnosing osteomyelitis?

Answer 13

Culture and histology of bone/aspirate.

Question 14

What type of therapy should be avoided in osteomyelitis?

Answer 14

Empirical treatment.

Question 15

What method of administration is best for ABX?

Answer 15

IV penetrate bone

Question 16

Antibiotics that penetrate bone well (5)?

Answer 16

Clindamycin (staph), ciprofloxacin (gram neg) Vancomycin (IV) beta lactams, gentamicin

Question 17

Staph aureus osteomyelitis treatment of choice ?

Answer 17

IV Flucloxacillin!

Question 18

Joint Infection occurs via what mechanism?

Answer 18

Haematogenous or trauma/surgery.

Question 19

What factors predispose to septic arthritis?

Answer 19

Rheumatoid arthritis, trauma, IV drug use and immunosuppressive disease.

Question 20

Predisposing factors for prosthetic joint infection?

Answer 20

Rheumatoid arthritis, prior surgery, steroid therapy, diabetes, poor nutrition, obesity, advanced age.

Question 21

Presentation of septic arthritis?

Answer 21

Pain, swelling, limitation of movement, systemic upset such as fever, chills sweats.

Question 22

Causative organism for septic arthritis?

Answer 22

Candida

bacteria- staph, strep, gram neg, anaerobes and myco tb

virus- rubella, parvo, mumps (usually self limiting)

Question 23

Native joint infection organisms?

Answer 23

Haemophilus influenzae, strep pyogenes, neisseria goborrhoea, neisseria meningitidis

Question 24

Prosthetic joint organism?

Answer 24

Coagulate negative staph, enterococci, corynebacteria, bacillus, propionibacteria (not usually severe normal flora low grade)

Question 25

Joint aspirate for septic arthritis what to look for?

Answer 25

White cell- >40k
WCC > 75% polymorphs
Crystal exam for gout

Question 26

Therapy for native joint infection?

Answer 26

Empirical ABX if needed
Joint washout
2-4 weeks therapy (native)

Question 27

Prosthetic infection therapy?

Answer 27

Removal if unstable joint
Washout possibly
Flucloxacillin + rifampicin for s aureus

Question 28

Never give which antibiotic alone for staph?

Answer 28

Rifampicin

Question 29

Which antibiotic combination for coagulate negative staph septic infection?

Answer 29

Rifampicin plus vancomycin can also be used for penicillin allergic.