Gangrene

Background

• A form of tissue necrosis characterized by critically insufficient blood supply leading to tissue death.
• Primarily divided into wet gangrene vs dry gangrene. Other, specific forms of gangrene include Fournier's gangrene, gas gangrene, and necrotizing fasciitis.
• Most commonly occur in distal extremities, clasically the feet.
• Main risk factors are diabetes, smoking, and peripheral arterial disease.
• Mainstays of treatment include surgical debridement and antibiotics.

Dry Gangrene

Clinical Features

• Usually due to peripheral arterial disease, but can also be caused by acute limb ischemia.
• Presents with dry, shrunken tissue, usually ranging from dark red to completely black, often with a clear line of demarcation between healthy and necrotic tissue. Typically not painful.

Evaluation

• History and physical examination are usually sufficient to make the diagnosis. If acute limb ischemia is suspected, consider a CTA of the affected limb and a vascular surgery consultation.

Management

• Infection rarely present, so management involves keeping the area clean and dry to prevent infection. Will usually auto-amputate in <6 months. Should be referred to vascular surgery as auto-amputation may not occur, and they may benefit from revascularization therapies to prevent further tissue death.
• If acute limb ischemia is present, embolectomy or surgical bypass may be required to restore flow.

Wet Gangrene

Clinical Features

• Usually due to peripheral arterial or venous disease, but can also be sequelae of trauma or burns causing vascular injuries.
• Presents with swollen, pale, soft tissue, often with a putrid smell and purulent discharge.
• As tissue is infected, wet gangrene presents a higher risk of systemic infection than dry gangrene.

Evaluation

• History and physical examination are usually sufficient to make the diagnosis.
• Given higher risk for systemic infection, patients should be evaluated for signs/symptoms of SIRS/sepsis, including a CBC, and possibly blood cultures and lactate if systemic infection is suspected.

Management

• Wet gangrene requires broad spectrum antibiotic coverage, as these are often polymycrobial infections.
• Requires surgical consultation as rapid debridement or amputation of necrotic tissue is required to prevent further spread of infection.