Gangrene

Question 1

Define gangrene

Answer 1

Tissue necrosis, either wet (w/ superimposed infection), dry or gas gangrene

Question 2

Aetiology of gangrene

4

Answer 2

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

Question 3

Risk factors for gangrene

7

Answer 3

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

Question 4

Epidemiology of gangrene

Answer 4

Relatively COMMON

Question 5

Presenting symptoms of gangrene

3

Answer 5

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

Question 6

Signs of gangrene on physical examination

4

Answer 6

Painful area = erythematous region around gangrenous tissue
Gangrenous tissue = BLACK because of haemoglobin break down products

Wet gangrene - tissue becomes boggy w/ associated pus & strong odour caused by activity of anaerobes
Gas gangrene - spreading infection & destruction of tissues causes overlying oedema, discolouration & crepitus (due to gas formation by infection)

Question 7

Investigations for gangrene

3

Answer 7

Bloods

Wound swab, pus/fluid aspirate

Xray of affected area

Question 8

Investigations for gangrene - bloods

5

Answer 8

FBC
U&Es
Glucose
CRP
Blood culture

Question 9

Investigations for gangrene - wound swab, pus/fluid aspirate

Answer 9

MC&S

Question 10

Investigations for gangrene - X-ray of affected area

Answer 10

May show gas produced in gas gangrene