Bone & Soft TIssue Infections Flashcards

1
Q

This deck covers:

A

Acute & Chronic Osteomyelitis
Septic Arthritis
TB

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2
Q

Who suffers from osteomyelitis?

A

Mostly kids, and generally boys with a trauma history

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3
Q

What are the common sources of OM infection?

A

Haematogenous - kids & elderly
Local spread from trauma & surgery

UTIs & arterial lines in adults
2* to vascular insufficiency
Infected Umbilical Cord in infants
Soft tissue infection

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4
Q

What organism is the mian cause of OM

A

1) Staph Aureus

It’s the biggest cause in any patient group. However certain groups (e.g. by age, co-morbidity or immunocompromise) are at risk of other specific organisms

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5
Q

What organisms cause OM in infants <1yr?

A

1) Staph Aureus
2) Group B Strep
3) E. Coli (most common if under <1month old)

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6
Q

What organisms cause OM in diabetics?

A

Staph Aureus

Mixed infection incl. Anaerobes

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7
Q

What organisms cause OM in Sickle Cell patients?

A

Staph Aureus

Salmonella

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8
Q

What organisms cause OM in HIV/AIDS patients?

A

Staph Aureus

Candida

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9
Q

Where in the bone is OM likely to arise?

A

The metaphysis of long bones or joints with an intra-articular metaphysis e.g. hip/elbow (this can lead to septic arthritis or arise from SA)

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10
Q

Describe the pathogenesis of OM?

A

Acute inflammation

  • > Increase Pressure
  • > Suppuration
  • > Pressure released into joint
  • > Necrosis of bone
  • > New Bone growth
  • > REsolves or Chronic
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11
Q

What do we call necrosed bone?

A

Sequestrum

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12
Q

What do we call new bone growth?

A

Involucrum

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13
Q

How might OM present in an infant?

A
Failure to thrive
~drowsy or irritable
Decreased movement or an odd position
Tenderness & swelling over metaphysis
Mostly in the knee
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14
Q

How might OM present in a child?

A

Severe pain +/- tenderness, fever and tachycardia
Systemic Symptoms e.g. fatigue, malaise & N&V

They won’t move or weight bear on that bone

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15
Q

How might primary OM present in an Adult?

A

MOstly in the thoracolumbar spine
So backache with a h/o UTI or urological procedure
Esp. in the elderly, diabetic or immunocompromised

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16
Q

How might secondary OM present in an adult?

A

Post an open fracture or surgery

17
Q

What tests could we do to diagnose OM?

A
FBC 
Differential WCC
U&Es
3x Blood cultures
MRI
X-ray
Bone biopsy
ESR & CRP

Also Aspiration, US, ISotope bone scan and labelled WC scan
And swabs from site during implantation surgery

18
Q

What would appear on an acute OM Diff. WCC?

A

Neutrophilic Leucocytosis

19
Q

What would appear on an Acute OM X-ray?

A

nothing in first 2 wks
10-20 days you get Early periosteal changes

Then you get late bone necrosis (Sequestrum) and LAte periosteal growth (Involucrum)

20
Q

DDX for Acute OM?

A

Acute Septic Arthrits (more common)
Acute Inflammatory Arthritis
Trauma
Transient Synovitis
Soft Tissue Infection (e.g. erysipelas or Cellulitis)
Rarely sickle cell, rheumatic fever, necrotising fasciitis or Gaucher’s Disease

21
Q

Treatment for Acute OM?

A

Supportive Care
Rest & Splintage
Abx
Surgery

22
Q

Whats included in supportive care for acute OM?

A

Fluids

Analgesia

23
Q

What Abx are used for Acute OM?

A

Empircally Flucloxacillin & Benzylpenicillin

4-6 wks on an IV/oral switch at 7-10 days

24
Q

When would we perform surgery for Acute OM?

A

Refractory to Abx after 48 hours
Debride dead/infected tissue
Drain abscess
Aspirate abscess for culture

25
Q

What surgical treatments do we have for Acute OM?

A

Drainage
Lavage
Infected joint replacement

26
Q

Complications of Acute OM?

A

Think spread of infection:

  • Septicaemia
  • Metastatic infection
  • Septic Arthritis

Think damage to bone:

  • Pathological fracture
  • Growth abnormality

Also Chronic OM

27
Q

How can Chronic OM originate?

A

Acute OM
De-novo (IVDA or ops in the elderly, immunosuppressed or diabetic)
repeated breakdown of ‘healed’ wounds

28
Q

What organisms cause Chronic OM?

A

1) Staph Aureus
2) E. Coli
3) Strep Pyogenes
4) Proteus
5) TB

29
Q

Complications of Chronic OM?

A
Metastatic Infection
Pathological fracture
Abnormal growth and deformity
Chronically discharging sinuses
SCC
30
Q

Treatment for Chronic OM?

A

Long Term Abx
Surgery
~Amputation

31
Q

What is the main causative organisms of Acute OM in adults?

A

Staph Aureus

Kids can get H influenzae and strep pyogenes

32
Q

Causative organisms of Acute OM in adults?

A

Adults can get:

  • Coagulase -ve staph from prosthetics
  • TB
  • Pseudomonas from IVDA & Penetrating foot injury

Staph Aureus is still the main cause