Gangrene = tissue death due to loss of blood supply, often complicated by infection.
⚠️ Common in patients with diabetes, peripheral arterial disease, or severe trauma.
Types:
- 🧊 Dry gangrene – ischaemic, non-infective.
- 🔥 Wet gangrene – infective, rapidly progressive.
- 💨 Gas gangrene – clostridial myonecrosis, fulminant, high mortality.

🧊 Dry Gangrene

💀 Pathophysiology: Gradual arterial insufficiency → ischaemic necrosis without infection.
👣 Affects distal extremities (toes, feet, fingers).
🟤 Clinical: shrivelled, black/brown, dry, well-demarcated.
😐 Symptoms: usually painless (nerve death).
🩺 Management: conservative auto-amputation in frail patients, surgical amputation if symptomatic. Optimise vascular supply (smoking cessation, statins, antiplatelets).

🔥 Wet Gangrene

🚨 Emergency - ischaemic necrosis + bacterial infection (often polymicrobial).
🩸 Clinical: severe pain, swelling, pus, foul odour, systemic sepsis (fever, tachycardia, hypotension).
⚠️ Risk groups: diabetics, trauma, burns, immunosuppressed.
⚡ Management: high-flow O₂, IV fluids, broad-spectrum antibiotics (benzylpenicillin + clindamycin + metronidazole), urgent surgical debridement/amputation ± ICU care.

💨 Gas Gangrene (Clostridial Myonecrosis)

Caused by Clostridium perfringens and related species, usually after contaminated wounds or surgery.
Pathophysiology: bacterial exotoxins cause myonecrosis, gas production, haemolysis, and systemic toxicity.
⚡ Clinical:
- Sudden, severe pain out of proportion to findings.
- Swelling, skin discolouration (bronze → purple → black).
- Crepitus (gas under skin, palpable crackles).
- Foul-smelling, thin discharge.
- Systemic sepsis, shock, multi-organ failure.
🔬 Investigations:
- X-ray/CT → gas in soft tissues.
- Gram stain → gram-positive rods without leucocytes (toxin-induced WBC lysis).
🚑 Management:
- Immediate resuscitation + broad-spectrum antibiotics (benzylpenicillin + clindamycin).
- Urgent radical surgical debridement or amputation.
- Consider hyperbaric oxygen therapy in specialist centres.

🔎 Causes of Gangrene

Dry: chronic ischaemia (PAD, diabetes, frostbite, atherosclerosis).
Wet: ischaemia + infection (trauma, burns, untreated dry gangrene).
Gas: Clostridial infection (contaminated wounds, deep tissue trauma, post-surgery).

🩻 Clinical Assessment

History: vascular risk factors, diabetes, recent trauma/surgery.
Examination: colour change, demarcation, infection signs, crepitus (gas).
Investigations: FBC, CRP, lactate, cultures, Doppler/angiography, imaging for gas.

⚖️ Management Principles

Dry: optimise circulation, conservative or surgical removal.
Wet: emergency antibiotics + surgery.
Gas: surgical debridement/amputation + antibiotics + hyperbaric O₂.

📊 Comparison Table


Feature	🧊 Dry Gangrene	🔥 Wet Gangrene	💨 Gas Gangrene
Cause	Chronic ischaemia (PAD, diabetes, frostbite)	Infection on top of ischaemia (trauma, burns)	Clostridial infection (trauma, contaminated wounds)
Appearance	Black, dry, shrivelled, well-demarcated	Swollen, red/black, blistered, foul-smelling, pus	Swollen, bronze → black, gas bubbles, crepitus
Pain	Minimal	Severe	Excruciating, out of proportion
Progression	Slow	Rapid	Very rapid, fulminant
Systemic Effects	None (unless infected)	Sepsis, hypotension	Toxaemia, shock, multi-organ failure
Management	Conservative or amputation, vascular optimisation	Emergency antibiotics + surgery	Urgent radical surgery, antibiotics, hyperbaric O₂

💡 Clinical Pearls: 👉 Gas gangrene is one of the most lethal surgical infections - time to theatre = survival. 👉 Wet gangrene always treat as a sepsis emergency. 👉 Optimising vascular risk factors in dry gangrene prevents progression.

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Dry and Wet and Gas Gangrene

📖 Introduction