Gangrene

Question 1

Define:

Answer 1

Tissue necrosis leading either wet superimposed infection dry or gas gangerene
due to poor vascular poor vascular supply

Dry - necrosis in the absence of infection

Wet - tissue death + infection

Gas - subset of necrotising myositis caused by spore- forming clostridial species

Question 2

Aetiology/risk factors:

Answer 2

tissue ischaemia + infarction

physical trauma

thermal injury

gas- colstidia perfrigens

Question 3

epidemiology:

Answer 3

relatively common

Question 4

symptoms:

Answer 4

pain

discolouration of affected area = black

often affects extremities or areas of high pressure

gas - rapid onset of myonecrosis, muscle swelling, gas production, sepsis + severe pain

Question 5

signs:

Answer 5

o 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)

Question 6

investigations:

Answer 6

bloods - FBC , U+E’s, glucose + CRP and blood culture

wound swab/ fluid aspirate

X-ray of affected area may show gas for gas gangrene