Definitions

• Wet gangrene: wet gangrene is an infectious type of gangrene that includes necrotising fasciitis (infection of the subcutaneous fascia and fat), gas gangrene (caused by Clostridium), and gangrenous cellulitis (typically found in immunocompromised individuals)
• Dry gangrene: dry gangrene is an ischaemic type of gangrene that occurs secondary to chronically reduced blood flow. Ischaemic gangrene can occur due to atherosclerosis (in association with peripheral arterial disease), thrombosis (in association with vasculitis and hypercoagulable states), and vasospasm (in association with cocaine use and Raynaud's phenomenon)

Clinical features

• Wet gangrene: in wet gangrene, the necrotic area is poorly demarcated from the surrounding tissue, and patients typically present with symptoms of fever and sepsis
• Dry gangrene: dry gangrene shows a well-demarcated necrotic area without signs of infection
  • Auto-amputation often occurs in these cases

Investigations

Wet gangrene

• Laboratory investigations: FBC, inflammatory markers (CRP, ESR), blood cultures to identify the causative organism, and lactic acid levels to assess the severity
• Imaging: X-ray, ultrasound, or CT scan to assess the extent of the disease and look for gas within the tissue
• Tissue biopsy: to confirm diagnosis and identify the causative organism

Dry gangrene

• Laboratory investigations: FBC, inflammatory markers (CRP, ESR) to rule out wet gangrene, glucose level to evaluate for diabetes, and coagulation profile in case of suspected hypercoagulability
• Imaging: Doppler ultrasound or angiography to assess blood flow and locate the site of blockage
• Tissue biopsy: Not typically needed but can confirm diagnosis if uncertain

Management

• Wet gangrene: management requires surgical debridement or amputation and broad-spectrum intravenous antibiotics
• Dry gangrene: management primarily includes surgical debridement or amputation, depending on the severity and extent of the necrosis