(Infection)

Overview

• Complication of necrosis characterised by the decay of body tissues
• Two Categories → Infectious Gangrene (Wet) or Ischaemic Gangrene (Dry)
  • Infectious Gangrene (Wet) → necrotising fasciitis or gas gangrene (caused by clostridium perfringes)
  • Ischaemic Gangrene (Dry) → PAD (critical limb ischaemia) due to atherosclerosis (arterial obstruction) or venous obstruction
• Risk Factors ⇒ diabetes, atherosclerosis, smoking, hypercoagulable states, malignancy, renal disease, alcoholism, malnutrition

Making Diagnosis

Clinical Features:

• Painful Black Tissue → may be history of chronic claudication with ischaemic gangrene. Sudden onset of pain is usually first symptom of infectious gangrene.
• Wet (Infectious) Gangrene ⇒ low-grade fever & chills
  • Poorly demarcated necrotic area
• Dry (Ischaemic) Gangrene ⇒ diminished pulses & ABPI (no signs of infection)
  • Well demarcated necrotic area
• Gas Gangrene ⇒ darkened skin. Crepitus may be heard due to escaping gas. Infective area gives off distinct and potent smell. May be able to visualise gas on radiograph (air bubbles on x-ray).
• Feeling of heaviness in affected area
• Oedema + Swelling
• Skin Discolouration (black tissue)

Investigations: