Gangrene

Question 1

Define gangrene

Answer 1

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

Question 2

Explain the aetiology/risk factors of gangrene

Answer 2

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

Risk Factors
Diabetes
Peripheral vascular disease
Leg ulcers
Malignancy
Immunosuppression
Steroid use
Puncture/surgical wound

Question 3

Summarise the epidemiology of gangrene

Answer 3

Gangrene - Common

Gas Gangrene - Rare

Question 4

Recognise the presenting symptoms of gangrene

Answer 4

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

Question 5

Recognise the signs of gangrene on examination

Answer 5

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

Identify appropriate investigations for gangrene

Answer 6

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