Gangrene is complication of necrosis characterised by the decay of body tissues. Results from ischaemia, infection, or trauma (or a combination of these processes).
Two main categories: infectious gangrene (which includes necrotising fasciitis and gas gangrene) and ischaemic gangrene (which can arise from arterial or venous obstruction).
Risk factors include diabetes, smoking, atherosclerosis, renal disease, drug and alcohol abuse, malignancy, trauma or abdominal surgery, contaminated wounds, malnutrition, hypercoagulable states, prolonged use of tourniquets, and community-acquired MRSA.
Successful treatment of infectious gangrene requires early recognition and a combination of aggressive surgical debridement, appropriate intravenous antibiotics, and intensive supportive care.
Ischaemic gangrene requires revascularisation for obstruction and thromboembolism, along with optimal treatment of any underlying disease. Measures to prevent superimposed infection must also be performed.
Prognosis is highly variable, but can involve significant morbidity and mortality.
Gangrene is a complication of necrosis characterised by the decay of body tissues. There are two major categories: infectious gangrene (wet gangrene) and ischaemic gangrene (dry gangrene). The condition may result from ischaemia, infection, or trauma (or a combination of these processes). Ischaemia may result from either arterial or venous compromise, and may be an acute or chronic process (or a combination of both). Critically insufficient blood supply is the most common cause of gangrene, and is often associated with diabetes and long-term smoking.
History and exam
Key diagnostic factors
- presence of risk factors
- oedema or swelling
- skin discoloration
- crepitus (gas gangrene)
Other diagnostic factors
- diminished pedal pulses and ankle-brachial index (ischaemic gangrene)
- low-grade fever and chills (infectious gangrene)
- diabetes mellitus
- atherosclerosis (ischaemic gangrene)
- smoking (ischaemic gangrene)
- renal disease
- drug and alcohol abuse
- trauma or abdominal surgery (infectious gangrene)
- contaminated wounds (infectious gangrene)
- immunosuppression (infectious gangrene)
- malnutrition (infectious gangrene)
- hypercoagulable states (ischaemic gangrene)
- prolonged application of tourniquets (ischaemic gangrene)
- community-acquired MRSA
1st investigations to order
- comprehensive metabolic panel
- serum LDH
- coagulation panel
- blood cultures
- serum CRP
- plain x-rays
- CT of affected site
- MRI of affected site
- Doppler ultrasonography
Investigations to consider
- surgical exploration and skin biopsy
- CT angiography
- magnetic resonance angiography (MRA)
- CT chest and abdomen
- antinuclear antibodies (ANA), lupus anticoagulant, anticardiolipin, and anti beta2 glycoprotein-1 antibodies
- serum cold agglutinins
- serum cryofibrinogens
- plasma cryoglobulin
necrotising fasciitis awaiting confirmation of microbial culture and sensitivity results
confirmed type I necrotising fasciitis (polymicrobial)
confirmed type II necrotising fasciitis (monomicrobial)
- Staphylococcal skin lesions
- Surgical site infections: prevention and treatment
- Management of chronic limb-threatening ischemia
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