Gangrene Flashcards
Define gangrene
Death of tissue from poor vascular supply (sign of critical ischaemia)
Complication of necrosis characterised by decay of body tissues
2 main categories: ischaemic (dry) and infectious gangrene (wet)
Aetiology of gangrene
Ischaemic: Atherosclerosis | diabetes-associated microangiopathy | thrombosis | IVDU | vasculitis | malignancy | antiphospholipid syndrome
Infectious: group A beta-haemolytic strep species | staph | non-group A strep | enterobacteriaceae
Gas: spore-forming gram +ve anaerobic clostridial species - C. perfringens
Risk factors for gangrene
Diabetes mellitus Trauma Malignancy Atherosclerosis Smoking Renal disease Drug and alcohol abuse Contaminate wounds Immunosuppression Malnutrition
Symptoms of gangrene
Rapid onset severe pain + muscle swelling/oedema + gas production + skin discolouration
Signs of gangrene
Crepitus (gas) Sepsis Myonecrosis Diminished pedal pulses and ABI (ischaemic) Low grade fever + chills (infectious) Cold extremities
Investigations for gangrene
Rapid progression, spread or clinical deterioration -> surgical exploration / biopsy to identify if the fascia is involved (necrotising fasciitis)
Bloods:
FBC (leucocytosis, haemochromatosis, anaemia)
CRP+ESR (elevated)
LDH (elevated in haemolytic anaemia)
Metabolic panel (metabolic acidosis , liver or renal derangement)
Blood cultures (infectious)
Plain X-rays (gas in soft tissues or osteomyelitis)
CT/MRI (abscess formation or evidence of enhancement, oedema or fascia involvement)
Doppler (indicate presence + severity of arterial or venous obstruction