AKT · Cardiovascular/Vessels, aorta & venouslow yield

Gangrene

Tissue necrosis from critical ischaemia (dry) or infection (wet/gas gangrene)

Overview

Death of tissue, classically of the extremities. Dry gangrene is ischaemic necrosis (PAD, diabetes, embolism) with a demarcated, mummified appearance and no infection. Wet gangrene is infected, spreading necrosis (a surgical emergency); gas gangrene (Clostridium perfringens) is a rapidly fatal myonecrosis. The split — dry vs wet/gas — drives whether the priority is revascularisation or emergency debridement/antibiotics.

Recognise

Dry: black, dry, mummified, well-demarcated tissue; cold, pulseless, painless once necrotic; chronic ischaemia/diabetes
Wet: swollen, malodorous, discharging, spreading necrosis with surrounding cellulitis and systemic sepsis
Gas gangrene: severe pain, crepitus, brawny oedema, rapidly spreading, systemic toxicity (Clostridium perfringens)

Red flags

Wet or gas gangrene with sepsis → surgical emergency: urgent debridement/amputation + broad-spectrum antibiotics + resuscitation
Necrotising fasciitis spectrum → do not delay surgical exploration

Differentials & how to tell them apart

Necrotising fasciitispain out of proportion, rapid spread, systemic toxicity — overlaps with wet/gas gangrene

Severe cellulitisinfection without established necrosis

Ischaemic ulceration without gangrenetissue still viable

Gangrene of the foot — necrotic, blackened tissue
James Heilman, MD / CC BY-SA 3.0 — Wikimedia Commons

Investigations

Assess perfusion (pulses, ABPI, angiography for revascularisation); wound swabs/blood cultures and inflammatory markers if infected; X-ray/CT for gas in tissues; glucose/HbA1c; lactate in sepsis.

Management

Dry → revascularise; wet/gas → emergency debridement/amputation + antibiotics + resuscitation

1Determine dry (ischaemic, demarcated, no infection) vs wet/gas (infected, spreading, septic). Assess perfusion and resuscitate if septic.Gate: Wet or gas gangrene with systemic sepsis → emergency surgical debridement/amputation, broad-spectrum antibiotics and resuscitation — source control cannot wait.
2Dry gangrene → revascularise the limb and optimise risk factors, with planned amputation or auto-amputation of necrotic tissue; long-term diabetes/PAD and foot care.

Dry gangrene: revascularise the limb + risk-factor control — restore perfusion; allow demarcation/auto-amputation or planned amputation of dead tissue

Wet/gas gangrene: emergency surgical debridement/amputation + IV broad-spectrum antibiotics + resuscitation — source control is the priority; cover anaerobes (e.g. with clindamycin) for gas gangrene

Treat the underlying cause — diabetes/PAD optimisation; foot care

Key points

Dry gangrene = demarcated, mummified, ischaemic, not infected → revascularise. Wet/gas gangrene = spreading, malodorous, septic (crepitus + severe pain = Clostridial gas gangrene) → emergency debridement/amputation + antibiotics + resuscitation. The infected forms are surgical emergencies.

Monitor & prognosis

Perfusion, sepsis markers, wound/stump healing, glycaemic control.

Dry gangrene is more indolent; wet/gas gangrene is limb- and life-threatening.

Source: Vascular/surgical guidance; cross-ref diabetic foot