Gangrene

Question 1

Definition

Answer 1

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

Question 2

Aetiology

Answer 2

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

Question 3

Risk factors

Answer 3

o Diabetes
o Peripheral vascular disease
o Leg ulcers
o Malignancy
o Immunosuppression
o Steroid use
o Puncture/surgical wounds

Question 4

Epidemiology

Answer 4

Relatively common

Gas gangrene is rare

Question 5

Presenting symptoms

Answer 5

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

Question 6

Signs on physical examination

Answer 6

o Painful area = erythematous region around gangrenous tissue

o Gangrenous tissue = BLACK because of haemoglobin break down products

o Wet Gangrene - tissue becomes boggy with associated pus and a strong odour caused by the activity of anaerobes

o Gas Gangrene - spreading infection and destruction of tissues causes overlying oedema, discolouration and crepitus (due to gas formation by the infection)

Question 7

Investigations

Answer 7

· 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