SU27.4 | Gangrene and Amputation Principles — Summary & Reflection

KEY TAKEAWAYS

Gangrene is macroscopic tissue death with putrefaction, and it is the convergence of ischaemia and infection. Dry gangrene results from gradual arterial occlusion without infection: the part is black, shrivelled and mummified with a clear line of demarcation, is indolent and can be managed in a planned way. Wet gangrene is necrosis with superadded infection (often venous obstruction too): swollen, foul, spreading and systemically toxic — an emergency. Special forms: gas gangrene (clostridial myonecrosis, C. perfringens, crepitus and toxaemia — a surgical emergency) and the diabetic foot (neuropathy + ischaemia + infection). Assess type, viability, blood supply (pulses, ABPI — falsely high in calcified diabetic vessels, toe pressures) and fitness; investigate with glucose/HbA1c, FBC/CRP, cultures and imaging for vessels and osteomyelitis. Amputation principles: treat the cause first (infection control, glycaemic control, revascularisation); indications are the three D's — Dead, Dangerous, Damn nuisance; choose the lowest level that will reliably heal with a functional stump (below-knee preferred over above-knee); build a viable stump and rehabilitate, watching for flap necrosis, infection and phantom limb pain.

REFLECT

Think about a patient with a diabetic foot or an ischaemic limb you have seen or may soon see. When you next examine a black toe or an infected foot, will you consciously decide whether it is dry or wet gangrene — and let that decision set the urgency of your response? Reflect on how much of diabetic limb loss is preventable through earlier recognition, good glycaemic control and foot care, and on the human weight of the level decision: that preserving a knee can mean the difference between independent walking and a wheelchair. Consider how you would counsel a patient facing amputation, both about the operation and about the rehabilitation that gives the procedure its purpose.