Orthopaedic Infection / Week 4 Elective Surgery

Question 1

the most common bacteria to infect an arthoplasty

Answer 1

its a draw —– staph epidermidis and staph aureas

Question 2

name 2 soft tissue infections

Answer 2

cellulitis

necrotizing fasciitis

Question 3

what is the anaerobic infection that may occur in an open fracture in a muddy farm accident?

Answer 3

Gram positive bacilli – clost perfringens .

Metronidazole (penicillin potentially too). Gentamicin wouldn’t work.

Question 4

how do you test for osteomyelitis?

Answer 4

bone biopsy

Question 5

pathogenesis of tetanus?

Answer 5

The spastic paralysis induced by the toxin is due to the blockage of neurotransmitter release from spinal inhibitory interneurons

Question 6

Tx of a dog bite causing tetanus?

Answer 6

Debridement

IV Penicillin +/- metronidazole

Antitoxin (Ig) + Booster vaccination

Question 7

alpha haemolytic strep (2)

what colour?

Answer 7

strep viridans
strep pneumoniae

GREEN

Question 8

what type of haemolysis is Group B Strep?
What the other name for Group B strep?
What type of infection does it cause?

Answer 8

beta haemolysis (clear)
“Agalactiae”
Group B strep causes neonatal meningitis

Question 9

what is Corynebacterium diphtheriae?

Answer 9

a aerobic small bacilli causing diptheria

Question 10

what is Listeria monocytogenes? what does it cause

Answer 10

a small aerobic bacilli that can cause meningitis

Question 11

2 different large aerobic bacilli?

Answer 11

bacillus cereus (food poisoning)
bacillus anthracis (anthrax)

Question 12

aeorobic bacteria : coccia and bacilli

within bacilli there are 3 types of clostridium, what are they?

Answer 12

Cl. tetani (tetanus)
Cl. perfringens (gas gangerene)
Cl. difficile (antibiotic associated colitis)

Question 13

what is involucrum?

Answer 13

new bone that forms round an area of necrosis

Question 14

what is sequestrum?

Answer 14

a fragment of dead bone

Question 15

what is brodie’s abscess?

Answer 15

subacute osteomyelitis, that has an incidious onset

basically there is an abscess which is surrounded by thin rim of sclerotic bone

Question 16

2 main sites of chronic osteomyelitis?

Answer 16

spine (mainly lumbar) and pelvis

Question 17

infection can spread to bone causing osteomyelitis. where does it typically come from?

Answer 17

1. lung - including pulmonary TB –> spine

2. UTI

Question 18

how long does it take for debrided bone to become vascularised again?

Answer 18

6 weeks

Question 19

if you have been giving IV fluclox for staph aureas but you want to switch to oral, what do you give?

Answer 19

oral Doxycycline

Question 20

what if they have a strep infection but are allergic fluclox?

Answer 20

IV vancomycin

Question 21

antibiotic for gram negatives?

Answer 21

gentamicin

Question 22

what are SAPHO and CROMO?

Answer 22

types of recurrent MULTIFOCAL osteomyelitis, associated with systemic upset

Sapho - adults
chromo - kids

Question 23

vertebral osteomyelitis can be a confusing presentation. why?

what additional features can occur?

Answer 23

only half have fever, and in 90% the pain is slow onset

there may be psoas/ epidural abscesses.

drain and give 6 weeks of antimicrobials

Question 24

what is pyomyositis?

Answer 24

a tropical bacterial skeletal muscle infection

tropical in geographical sense - the actual causing bacteria is staph aureas in 90% of cases. normally have an abscess.

Question 25

what is myositis?

Answer 25

NON BACTERIAL SKELETAL MUSCLE INFECTION…ie
viral - diffuse
fungal - focal
parasitic eg schistosomiasis.

Question 26

What is Pott’s disease?

Answer 26

Another name for Vertebral TB, which can cause Vertebral Osteomyelitis.

not infectious + no cough

Question 27

treatment of Staph aureas’ PVL??????

Answer 27

linezoid and clindamycin

Question 28

what type of haemolysis is Group A strep?

what is it’s other name?

Answer 28

Beta haemolysis (clear)
Strep pyogenes

Question 29

the duration of antibiotics given for staph aureus infection depends on where it is….
skin / soft tissue ?
blood?
bone?

Answer 29

skin = 7 days
blood = 14 days
bone = 6 weeks

Question 30

flucloxacillin is given for staph aureus. what is given for MRSA?

Answer 30

Vancomycin

Question 31

which bone is most commonly targeted by haematogenous spreading osteomyelitis?

what other part of the body is at risk of infection?

Answer 31

the femur

the heart valves, causing endocarditis

Question 32

what bacteria is most common in haematogenous spreading osteomyelitis?

Answer 32

staph aureus

Question 33

what specific groups of people get osteitis pubis infections (OM) ?

Answer 33

1. athletes (acute)

2. post-urogynae operations

Question 34

sickle cell anaemia patients get osteomyelitis, caused by staph aureas and what other infection

clue: common food bacteria

Answer 34

salmonella

Question 35

what is the “empirical” treatment of septic arthritis

• in adults
• in children

Answer 35

Flucloxacillin (as staph aureus is most common)

Add Cefriaxone to cover H.influenza in children

Question 36

Gram + strictly anaerobic rods with spores - what am I ??

Answer 36

tetanus

clostridium tetani