OVERVIEW

What are bacteria?

Bacteria are a type of microorganism. Based on their shape, they can be classified into cocci (spherical under a microscope, not visible to the naked eye), bacilli (rod-shaped under a microscope), and spirilla (spiral-shaped under a microscope). Based on their oxygen requirements, they are divided into aerobic bacteria (requiring oxygen to survive) and anaerobic bacteria (requiring an oxygen-free environment to survive). Although bacteria can only be observed under a microscope, they are "small but complete," with each bacterium possessing structures such as a cell wall, cell membrane, cytoplasm, and nuclear material. Some specialized bacteria may also contain unique structures, such as spores (dormant forms of bacteria with strong resistance to environmental conditions) and capsules.

What is gas gangrene?

Gangrene refers to the necrosis of local tissues followed by infection with putrefactive bacteria. Gas gangrene is a type of gangrene, specifically referring to muscle necrosis or myositis caused by Clostridium bacteria.

Gas gangrene can be divided into two types: traumatic gas gangrene and spontaneous gas gangrene:

• Traumatic gas gangrene is most commonly caused by Clostridium perfringens;

• Spontaneous gas gangrene is most commonly caused by Clostridium septicum.

Is gas gangrene common? Is it serious?

This disease was highly prevalent during wartime but is now rare in peaceful times. However, once it develops, the condition progresses rapidly, changing every hour. Some patients may require amputation or even lose their lives due to this disease.

Is gas gangrene contagious?

Gas gangrene is considered an infectious disease but not a contagious one.

SYMPTOMS

What are the typical manifestations of gas gangrene?

Traumatic gas gangrene:

• Local symptoms: Sudden, severe pain at the surgical or traumatic site is common. The skin in the infected area may initially appear pale, then rapidly progress to a bronze color, followed by purple or red. The skin becomes tense and highly sensitive to pressure. Blisters on the skin surface may be clear, red, blue, or purple.

• Systemic symptoms: Signs of systemic toxicity may develop rapidly, including tachycardia and fever, followed by shock and multi-organ failure.

Spontaneous gas gangrene:

• Local symptoms: Sudden, severe muscle pain is typically reported. Occasionally, a sensation of heaviness or numbness may be described. The infection progresses rapidly, leading to edema and blisters filled with clear, cloudy, bloody, or purple fluid. The skin surrounding the blisters turns purple, likely reflecting compromised blood supply due to bacterial toxin spread to surrounding tissues.

• Systemic symptoms: In some patients, the initial presentation may be confusion or malaise.

CAUSES

What are the causes of gas gangrene?

At least three conditions must be met for the disease to occur:

• Infection with Clostridium: Common Clostridium species that cause this disease include Clostridium perfringens, Clostridium novyi, Clostridium septicum, and Clostridium histolyticum. Among these, the former is the most common, often resulting from co-infection by multiple bacteria.

• Anaerobic environment: The Clostridium bacteria that cause infection are widely present in environments such as human and animal feces and soil, making contamination likely. However, few cases progress to disease because these bacteria require an anaerobic environment to grow and reproduce.

• History of trauma: Events such as car accidents or war injuries leading to poor local tissue blood supply and tissue necrosis.

Additionally, poor immune resistance can accelerate disease progression.

In what situations is traumatic gas gangrene most common?

Conditions associated with traumatic gas gangrene include: intestinal and biliary tract surgery, gunshot wounds, stab wounds, compound fractures, miscarriage, retained placenta, prolonged rupture of membranes, intrauterine fetal death, intramuscular injections, and black tar heroin injections.

In what situations is spontaneous gas gangrene most common?

Spontaneous gas gangrene typically occurs when bacteria from the gastrointestinal tract (usually Clostridium septicum) spread to muscles through the bloodstream. It may also occur in patients with congenital or cyclic neutropenia or those who have undergone prior abdominal radiotherapy.

How soon after injury does gas gangrene develop?

Infection with these pathogenic bacteria after an injury does not always lead to disease. If symptoms appear, the shortest onset time is 8–10 hours, while the longest is 5–6 days, typically occurring 1–4 days after the injury.

Can gas gangrene occur in any infected body part?

As long as the conditions for gas gangrene are met, it can occur in any part of the body. However, clinically, it is more common in severe trauma near the perianal and perineal areas, open fractures combined with vascular injuries, and crush injuries involving deep muscle damage.

DIAGNOSIS

What tests are needed to diagnose gas gangrene?

The main auxiliary tests for diagnosing this disease include complete blood count (CBC), secretion smear, secretion culture, and X-ray or CT:

• Complete Blood Count (CBC): A blood test that is not specific for diagnosing this disease (i.e., cannot confirm the diagnosis) but can reveal changes in white blood cells and red blood cells. This test is simple, inexpensive, provides quick results, and can be repeated to dynamically monitor disease progression.

• Secretion Smear: Microscopic examination of wound secretions can roughly identify the type of bacteria (Gram-positive? Gram-negative? Cocci? Bacilli?). This test is inexpensive and provides rapid results. However, the detection of Gram-positive bacilli alone cannot directly confirm the diagnosis.

• Secretion Culture: Bacterial culture of secretions, though time-consuming, can confirm the pathogenic bacteria if the culture is positive.

• X-ray or CT: The examination site is determined based on the injured area. These tests can detect deep-seated gas accumulation that is difficult to observe with the naked eye at an early stage. A positive result aids in confirming the diagnosis.

The diagnosis of this disease primarily relies on medical history, symptoms, physical examination abnormalities, and a comprehensive evaluation of the above tests.

TREATMENT

Which department should I visit for gas gangrene?

Gas gangrene is primarily treated with surgical debridement, so the department to visit depends on the location of the injury, such as orthopedics, proctology, or infectious diseases. It is generally not treated in the infectious diseases department.

How is gas gangrene usually treated?

Early diagnosis and treatment are crucial for this condition, as earlier intervention yields better outcomes. Key treatments include surgical debridement and antibiotic therapy, mainly divided into:

• Antibiotic use: The primary goal is to kill bacteria, with penicillin being the first choice. However, high doses and early administration are essential. For those allergic to penicillin, clindamycin can be used as an alternative.

• Emergency debridement: This is the key to treating the disease. It removes necrotic tissue and improves the anaerobic environment to inhibit further bacterial growth. The initial procedure requires extensive incision and drainage, followed by debridement and irrigation once or twice daily. Secondary suturing is considered only when fresh granulation tissue appears in the wound.

• Hyperbaric oxygen therapy: This is an absolute indication for hyperbaric oxygen treatment. However, the hyperbaric chamber must be strictly disinfected, and single-chamber therapy is required. Its practical application is relatively limited.

• Systemic supportive therapy: Includes nutritional support, correction of water and electrolyte imbalances (e.g., potassium, sodium ions), and blood transfusion if necessary based on the patient's condition.

DIET & LIFESTYLE

None.

PREVENTION

How to prevent gas gangrene?

The general principle for preventing gas gangrene: After traumatic injury, perform thorough debridement as early as possible, administer adequate antibiotics promptly, and provide systemic supportive treatment.

Is there a vaccine to prevent gas gangrene?

Tetanus has a vaccine, but there is no vaccine for this disease.