Gangrene and Necrotising Fasciitis Flashcards
Define gangrene
tissue necrosis, either wet with superimposed infection, dry or gas gangrene
Define Necrotising Fasciitis
a life-threatening infection that spreads rapidly across fascial planes
Explain the aetiology- Gangrene
Tissue ischaemia and infarction
Physical trauma
Thermal injury
Gas gangrene is caused by Clostridia perfringens
Explain the aetiology- Necrotising Fasciitis
Usually polymicrobial involving streptococci, staphylococci, bacterioides and coliforms
Risk Factors
Diabetes
Peripheral vascular disease
Leg ulcers
Malignancy
Immunosuppression
Steroid use
Puncture/surgical wounds
Summarise the epidemiology of gangrene and necrotising fasciitis
Gangrene - relatively COMMON
Necrotising fasciitis and gas gangrene - RARE
Recognise the presenting symptoms of
Pain
Discolouration of affected area
Often affects extremities or areas subject to high pressure
Recognise the presenting symptoms of Necrotising Fasciitis
Pain
Often seems SEVERE and out of proportion to the apparent physical signs
Predisposing event (e.g. trauma, ulcer, surgery)
Recognise the signs of gangrene on examination
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)
Recognise the signs of necrotising fasciitis on examination
Area of erythema and oedema
Haemorrhagic blisters may be present
Signs of systemic inflammatory response and sepsis (high/low temperature, tachypnoea, hypotension)
Identify appropriate investigations for gangrene and necrotising fasciitis
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
