6: Bone and joint infections Flashcards Preview

MSK Week 3 2017/18 > 6: Bone and joint infections > Flashcards

Flashcards in 6: Bone and joint infections Deck (46)
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1
Q

Infection presents with all the cardinal features of ___, but not all ___ is infectious.

A

inflammation

2
Q

What are the cardinal features of inflammation?

A

Rubor - redness

Calor - hot

Dolor - painful

Tumor - swelling

Loss of function

3
Q

Generally, when should you start antibiotics?

What are the exceptions?

A

When you know for sure that it’s an infection - through investigation

If the patient is imminently going to die / lose stuff - sepsis, necrotising fasciitis

4
Q

How long should suspected bone and joint infection specimens be cultured for?

A

1 week

otherwise standard 48hrs

5
Q

What are some inflammatory markers analysed in blood tests?

A

CRP

PV

ESR

6
Q

What cells pick up technetium?

A

Osteoblasts

So scan indicates increased turnover, metabolic activity

7
Q

What does MRI pick up as opposed to X-ray?

A

Soft tissue swelling, fluid

Useful for seeing pus-filled abscesses in osteomyelitis

8
Q

What is osteomyelitis?

A

Infection of bone

9
Q

What is the most common means of developing acute osteomyelitis?

A

Post-trauma / open fractures

10
Q

By which means may infection get to bone in children and immunosuppressed people?

A

Haematogenous spread (via blood)

11
Q

Which bugs are usually responsible for acute osteomyelitis in:

a) adults
b) children?

A

a) Adults - Staph. aureus

b) Kids - Haemophilus

12
Q

What must be done to open fractures to reduce the risk of osteomyelitis?

A

Debridement

13
Q

What process gives pathogens an opportunity to spread to bone via blood vessels?

A

Thrombosis

revise virchow’s triad

14
Q

Which scan is good for picking up osteomyelitis?

A

MRI scan

15
Q

If there’s pus in a wound, what should you do?

A

Drain it

16
Q

Why don’t antibiotics help when abscesses are involved in osteomyelitis?

A

Abscess has no blood supply so antibiotic won’t penetrate it

17
Q

What can the drained pus from an abscess be used for?

A

Culture

18
Q

What is sequestrum?

A

Dead bone

19
Q

Does sequestrum has a blood supply?

A

No

20
Q

Sequestrum should be (removed from / left in) a wound.

A

removed from

21
Q

What occurs if acute osteomyelitis isn’t treated?

A

Chronic osteomyelitis

22
Q

If chronic osteomyelitis isn’t treated, where can the pus go?

What happens to bone as a result of the pus?

A

Joint cavities

Underneath periosteum

More bone death

23
Q

What is an involucrum?

A

Growth of new bone around sequestrum as seen in osteomyelitis

24
Q

Which joint infection aggressively destroys joints within 1-2 days?

A

Septic arthritis

25
Q

Septic arthritis tends to affect (adults / children).

A

children

26
Q

If a joint space reappears on X-ray in a patient with osteoarthritis, what’s happened?

A

Filled with pus

Patient has septic arthritis

27
Q

What conditions are associated with septic arthritis?

A

Sepsis

Septicaemia

28
Q

Does osteomyelitis lead to septic arthritis?

A

Can do

and vice versa

29
Q

What does dark bubbles in soft tissue on a X-ray indicate?

A

Gas-forming organisms in soft tissue

Patient may have crepitus

30
Q

Soft tissue infection doesn’t produce any pus early on. What are good “best guess” antibiotics used to treat it?

A

Flucloxacillin

Benzylpenicillin

31
Q

Which soft tissue infection, causing severe pain, causes death within days if not treated?

What sign may they have on palpation?

A

Necrotising fasciitis

Crepitus - gas forming organisms in soft tissue

32
Q

How is necrotising fasciitis treated?

A

Removal of all affected tissue

33
Q

Samples obtained from debridement and pus draining can be used for what?

A

Biopsy

Culture

34
Q

In which groups of patients should back pain be taken very seriously?

A

Red flag patients

Children

Teenagers

35
Q

What is septic arthritis called if it’s found in the intervertebral discs?

A

Discitis

36
Q

What organism tends to cause discitis?

A

Staph. aureus

37
Q

Patients with discitis are given ___ and only operated on if they don’t respond. Why?

A

antibiotics

Spine is really difficult to operate on

38
Q

What foreign body, found in joints, can become infected?

A

Joint replacements

39
Q

What types of Staph. are associated with prosthetic joint infections?

A

Coagulase negative Staph.

e.g staph epidermidis

40
Q

What is produced by microbes in joints, making treatment with antibiotics difficult?

A

Biofilms

slimy stuff

41
Q

Demarcation of the bone and cement surfaces around prosthetic joints indicates ___ of the joint secondary to what?

A

loosening of prosthetic joint

Infection

42
Q

What must be released from infected prosthetic joints?

A

Pus

43
Q

How are operating theatres kitted out to reduce rates of infection?

A

Air control - clean filtered air pumped in via laminar flow diffuser

44
Q

What other factors affect the rate of infection in operating theatres?

A

Hand washing (5 mins)

Neat surgery

45
Q

What is given to the patient as infection prophylaxis before surgery?

A

Antibiotics

4Cs, flucloxicillin

46
Q

sa and se most responsible for infections

mrsE treated with tychoplanin

A