Life-threatening necrotizing infection of muscle (myonecrosis) caused by toxin-producing *Clostridium* (usually *C. perfringens*), with rapid tissue necrosis and gas production in the wound.
100% fatal if untreated (even with treatment, significant mortality). Requires emergent surgical intervention to prevent death. High-yield on exams as a classic example of a necrotizing soft tissue infection that demands immediate recognition and action.
Usually follows trauma or surgery: sudden severe pain at the wound site (often out of proportion to exam), with swelling and skin color changes (pale → bronze → purple) and tense edema. Wound discharge is often thin, brown, foul-smelling ('dishwater' fluid). Crepitus (gas) is felt in the tissue.
Rapid systemic progression: high fever, tachycardia (disproportionately high relative to fever), and hypotension (septic shock). Clostridial toxins can cause hemolysis; advanced cases may develop DIC and multi-organ failure.
Risk factors: deep penetrating wounds (war injuries, farm accidents, crush injuries) or post-surgical infections (especially after bowel surgery with gut flora contamination). Conditions like diabetes, peripheral vascular disease, or injection drug use predispose to poor wound healing. Spontaneous gas gangrene (no trauma) is rare but occurs with *Clostridium septicum* in patients with occult colonic malignancy or neutropenia.
If a necrotizing infection is suspected (severe pain, crepitus, rapid progression), treat as a surgical emergency – call for immediate surgical evaluation (do not wait for labs or imaging).
Obtain a rapid Gram stain of wound exudate: the hallmark is Gram-positive rods with few or no neutrophils, confirming clostridial myonecrosis. Send cultures, but do not delay therapy waiting for results.
Imaging (X-ray or CT) can show gas in soft tissues and delineate the spread, but a normal scan does not rule it out. If clinical suspicion is high, proceed to surgery regardless of imaging.
Start broad-spectrum IV antibiotics promptly. Include high-dose penicillin G plus clindamycin to specifically target clostridia and inhibit toxin production (clindamycin is bacteriostatic but shuts down toxin release).
necrotizing infection of fascia (often streptococcal or polymicrobial); similar rapid spread but usually more subcutaneous/skin involvement and typically less gas formation.
common soft tissue infection (streptococcal or staph); causes redness and swelling of skin but no gas or deep muscle necrosis.
Clostridial cellulitis
gas-producing *Clostridium* infection confined to subcutaneous tissue; causes crepitus but spares muscle (less pain and systemic toxicity than gas gangrene).
Aggressive surgical debridement is the first-line treatment – urgently remove all necrotic muscle (often requiring amputation of the affected limb). Repeat debridements may be needed until the infection is controlled.
High-dose IV penicillin G plus clindamycin should be started as soon as gas gangrene is suspected (do not wait for confirmation). Clindamycin is included to inhibit toxin production. Broad-spectrum coverage for other organisms is often added empirically.
Hyperbaric oxygen therapy (100% O₂ at high pressure) is a useful adjunct after surgery and antibiotics, as it kills anaerobes and halts toxin production – it can significantly improve survival if available.
Provide intensive supportive care: IV fluids and vasopressors for shock, monitor for organ failure (renal failure, DIC), and ensure appropriate tetanus prophylaxis for the wound.
Gram stain clue: absence of neutrophils in a wound with lots of bacteria strongly suggests clostridial infection (toxins lyse WBCs).
*C. perfringens* produces alpha toxin (lecithinase), a phospholipase that destroys cell membranes → rapid tissue necrosis and hemolysis (classic double-zone of hemolysis on blood agar).
Spontaneous gas gangrene (no trauma) = think *C. septicum* and look for hidden colon cancer (this organism often infects immunosuppressed or malignancy patients).
Any infected wound with crepitus (gas under the skin) and excruciating pain/tachycardia is a red flag for necrotizing infection (gas gangrene or necrotizing fasciitis) – requires immediate surgical attention.
Unprovoked (spontaneous) myonecrosis in a patient without trauma is extremely concerning for *Clostridium septicum* infection – screen for an underlying colon tumor or immunodeficiency.
Suspicion of gas gangrene (necrotizing infection with gas) → Immediate surgical consult (do not delay).
Begin IV antibiotics (broad-spectrum, include penicillin + clindamycin) empirically as soon as possible.
Emergent surgical exploration & debridement of the affected area (remove all dead tissue; often amputation is necessary).
Obtain wound cultures and Gram stain during surgery to confirm *Clostridium* species, but continue aggressive treatment regardless of pending results.
After initial surgery, consider hyperbaric oxygen therapy to improve patient survival, along with ongoing ICU support and repeat debridements as needed.
Middle-aged patient with a deep puncture wound (e.g., farm injury) who develops sudden extreme wound pain, swelling with bronze discoloration and foul brown discharge, plus crepitus on palpation and signs of shock → Gas gangrene (clostridial myonecrosis) requiring emergent debridement.
Immunosuppressed patient (e.g., with colon cancer) with acute limb pain and swelling, crepitus in the muscle, and severe sepsis without an external wound → Spontaneous gas gangrene due to *C. septicum*.
Case 1
A 45‑year‑old man presents with severe pain and swelling of his left thigh, two days after suffering a deep puncture wound on a farm.
X-ray of an amputated leg stump showing gas gangrene infection, with dark gas pockets in the soft tissue (highlighted by arrows).
