MSK Infections Flashcards Preview

Musculoskeletal > MSK Infections > Flashcards

Flashcards in MSK Infections Deck (40)
Loading flashcards...
1
Q

What is osteomyelitis?

A

Inflammation of bone and medullary cavity, usually located in one of the long bones

2
Q

How can osteomyelitis be classified?

A

Acute or chronic, contiguous or haematogenous, host status

3
Q

What is needed for a bone to become infected?

A

Only with necrosis +/- high inoculum

4
Q

What are the principles of surgery for osteomyelitis?

A

Remove infected tissue, drain and debride (may recur after treatment)

5
Q

When should antimicrobials be given before culture results have been obtained?

A

Sepsis syndrome or soft tissue infection

6
Q

What are some appropriate cultures?

A

Percutaneous aspirate or deep surgical cultures

7
Q

When are sinus/drain cultures useful?

A

If they yield staph. or resistant organisms

8
Q

What are some antibiotics active against staph. aureus?

A

Flucloxacillin (MSSA only), doxycycline, vancomycin, cotrimoxazole, teicoplanin, linezolid, daptomycin, clindamycin

9
Q

What are some causes and classes of osteomyelitis?

A

Open fracture, diabetes/vascular insufficiency, haematogenous, vertebral, prosthetic joint infections

10
Q

What are some features of osteomyelitis caused by open fractures?

A

Polymicrobial, contiguous infection, staph. aureus and aerobic gram negative bacteria, symptoms are non-union and poor wound healing

11
Q

How is open fracture osteomyelitis treated?

A

Early management is key = aggressive debridement, fixation, soft tissue cover

12
Q

What are some features of osteomyelitis caused by diabetes/venous insufficiency?

A

Polymicrobial, diagnosed by a probe to the bone, treated by debridement and antimicrobials

13
Q

What is the gram positive cover used to treat diabetes-linked osteomyelitis?

A
Flucloxacillin = IV, for staph (and strep)
Vancomycin = people with penicillin allergy (can't take fluclox)
Doxycycline = oral switch, excellent bone penetration
14
Q

What is the gram negative cover for diabetic osteomyelitis?

A

Gentamicin/aztreonam IV if severe
Oral cotrimoxazole/doxycycline if able to use oral route
Only if needed

15
Q

What antibiotic is used to treat anaerobic organisms that may cause osteomyelitis in diabetics?

A

Metronidazole

16
Q

What are significant causative organisms of osteomyelitis in patients with diabetes?

A

Staph. aureus, Groups A-C strep, Milleri group, anaerobes

17
Q

What colonisers may be present in an osteomyelitis infection in a diabetic?

A

P. aeruginosa, E.coli, proteus, klebsiella, Enterobacter, bacillus sp, coagulase negative staph
May be present on culture but not causing infection = only prescribe antibiotics if signs of infection in patient

18
Q

What patient groups get haematogenous osteomyelitis?

A

Prepubertal children, people who inject drugs, central lines/dialysis/elderly

19
Q

What are some features of haematogenous osteomyelitis?

A

Caused by presence of bacteria in blood, acute onset illness

20
Q

What are some features of haematogenous osteomyelitis in IV drug users?

A

Spread = haematogenous, contiguous, direct inoculation

Unusual sites = SCJ, SChoJ, SIJ, pubic symphysis

21
Q

What organisms cause haematogenous osteomyelitis in IV drug users?

A

Most commonly staph. and strep

Less commonly pseudomonas, candida, eikenella corrodens (needle lickers) and myobacterium tuberculosis

22
Q

What are some features of haematogenous osteomyelitis in dialysis patients?

A

7% with tunnelled line, high staph. colonisation rates, peripheral vascular disease and diabetes are risk factors, staph. aureus is most common cause, sometimes gram negative organisms are the cause

23
Q

What are some examples of unusual site osteomyelitis?

A

Osteitis pubis and Clavicle osteomyelitis

24
Q

What are some features of osteitis pubis?

A

Predisposed by urogenital procedures

Aseptic osteitis pubis = triggered by surgery, can be up to 18 months later, athletes get it

25
Q

What are some features of clavicle osteomyelitis?

A

3% of osteomyelitis cases

Risk factors = neck surgery, subclavian vein catheterisation

26
Q

What are some unusual patient groups that get osteomyelitis?

A

Sickle cell osteomyelitis, Gaucher’s disease, SAPHO/CRMO

27
Q

What are some features of sickle cell osteomyelitis?

A

Most commonly salmonella, also staph. aureus, occurs in 12% of homozygotes, acute long bone osteomyelitis
Differentials = bone infarction, septic arthritis

28
Q

What are some features of Gaucher’s disease?

A

Lysosomal storage disorder, may mimic bone crisis, often affects tibia, staph. aureus if infected

29
Q

What do SAPHO and CRMO stand for?

A

Synovitis Acne Pustolosis Hyperostosis Oseitis = adults

Chronic Recurrent Multifocal Osteomyelitis = children

30
Q

What are needed to exclude osteomyelitis when considering SAPHO/CRMO?

A

History plus culture samples crucial

31
Q

What are some features of SAPHO/CRMO?

A

Raised inflammatory markers, lytic lesions on x-ray, fever, weight loss, generalised malaise, multi focal osteitis, self-limiting, exacerbations and remissions, genetics and propionbacterium play a role

32
Q

Where are some sites affected by SAPHO/CRMO?

A

63% chest, 40% pelvis, 33% spine, 6% lower limb

5 or so active lesions per patient

33
Q

What are some examples of vertebral osteomyelitis?

A

Spondylodiscitis and disc space infection

34
Q

How is vertebral osteomyelitis spread?

A

Haematogenous spread

35
Q

What are some associations and comorbidities of vertebral osteomyelitis?

A

May be associated with epidural or psoas abscesses

Comorbidities = IV drug use, IV site infections, GU infections, SSTI, post-operative

36
Q

What are the symptoms of vertebral osteomyelitis?

A

Fever, insidious pain and tenderness, neurological signs, raised inflammatory markers, abnormal plain film and raised white cell count may be present

37
Q

What investigations are done for vertebral osteomyelitis?

A

MRI, Ga-67 scan (FDG-PET)

38
Q

What is the treatment for vertebral osteomyelitis?

A

Drainage of large paravertebral/epidural abscesses
Antimicrobials for 6 weeks minimum (pathogen specific)
Expect >50% decrease in ESR
Duration extended in complicated cases

39
Q

When should MRIs be repeated for vertebral osteomyelitis?

A

Only if unexplained increase in inflammatory markers, increasing pain or new anatomically related signs/symptoms

40
Q

What is the gold standard investigation for osteomyelitis?

A

Bone biopsy

Decks in Musculoskeletal Class (57):