Gangrene and necrotising fasciitis Flashcards

1
Q

Define

A

DEFINITION:

Gangrene - tissue necrosis, either wet with superimposed infection, dry or gas gangrene

Necrotising Fasciitis - a life-threatening infection that spreads rapidly across fascial planes

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2
Q

Causes

A

Gangrene

  • Tissue ischaemia and infarction
  • Physical trauma
  • Thermal injury
  • Gas gangrene is caused by Clostridia perfringens

Necrotising Fasciitis
- Usually polymicrobial involving streptococci, staphylococci, bacterioides and coliforms

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3
Q

Risk factors

A

Diabetes

Peripheral vascular disease

Leg ulcers

Malignancy

Immunosuppression

Steroid use

Puncture/surgical wounds

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4
Q

Epidemiology

A

Gangrene - relatively COMMON

Necrotising fasciitis and gas gangrene - RARE

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5
Q

Symptoms

A

Gangrene:

  • Pain
  • Discolouration of affected area
  • Often affects extremities or areas subject to high pressure

Necrotising Fasciitis
Pain
- Often seems SEVERE and out of proportion to the apparent physical signs
Predisposing event (e.g. trauma, ulcer, surgery)

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6
Q

Signs

A

Gangrene

  • Painful area = erythematous region around gangrenous tissue
  • Gangrenous tissue = BLACK because of haemoglobin break down products
  • Wet Gangrene - tissue becomes boggy with associated pus and a strong odour caused by the activity of anaerobes
  • Gas Gangrene - spreading infection and destruction of tissues causes overlying oedema, discolouration and crepitus (due to gas formation by the infection)

Necrotising Fasciitis

  • Area of erythema and oedema
  • Haemorrhagic blisters may be present
  • Signs of systemic inflammatory response and sepsis (high/low temperature, tachypnoea, hypotension)
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7
Q

Investigations

A

Bloods - FBC, U&Es, glucose, CRP and blood culture

Wound Swab, Pus/Fluid Aspirate - MC&S

X-ray of affected area - may show gas produced in gas gangrene

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