Gas gangrene is a life-threatening infection of muscle tissue caused mainly by the anaerobic bacteria Clostridium perfringens and several other species of clostridia.
Gas gangrene can develop after certain types of surgery or injuries.
Blisters with gas bubbles form near the infected area, accompanied by fever, rapid heartbeat and breathing, and often pain at the infection site.
Symptoms suggest the diagnosis, and imaging tests or culture of a sample taken from infected tissue is usually done.
Treatment involves high doses of antibiotics and surgical removal of dead or infected tissue.
Gas gangrene is a fast-spreading clostridial infection of muscle tissue that, if untreated, quickly leads to death.
Several thousand cases of gangrene occur in the United States every year.
Clostridia thrive when no oxygen is present. That is, they are anaerobes. So they reproduce well in soft tissues that have been severely damaged and in wounds that are very deep. Such tissues have poor blood flow and thus low oxygen levels.
Most clostridial soft-tissue infections, including gas gangrene, are caused by Clostridium perfringens. Clostridial soft-tissue infections usually develop hours or days after an injury but sometimes take several days to appear.
Other clostridial soft-tissue infections include
Infections of the inner layer of skin and surrounding soft tissues (cellulitis), which may not be very painful
Deeper infections into fibrous tissue around the muscles called fascia (fasciitis) or muscle (myositis), which usually are painful
Skin infections rarely spread and become serious.
Sometimes the bacteria in soft tissues produce large amounts of gas as a waste product. The gas can form bubbles and blisters in tissue. Often, the infection blocks small blood vessels. As a result, the infected tissue dies. The dead tissue enables the clostridial infection to spread even faster. Gas gangrene is more likely to develop when muscle is infected than when only the skin is infected.
Causes of Gas Gangrene
Gas gangrene usually develops after injuries or surgery. High-risk injuries include wounds that
Are deep and severe
Involve muscle
Are contaminated with dirt, decaying vegetable matter, or stool
Contain crushed or dead tissue
High-risk surgery includes
Operations on the large intestine (colon) or gallbladder
Rarely, gas gangrene occurs when there is no injury or surgery—usually in people with colon cancer, diverticulitis, or a disorder that reduces blood flow to the intestine or results in leaks through the wall of the intestine. Gas gangrene may develop when bacteria that live in the intestine leak out. The bacteria can spread widely.
Symptoms of Gas Gangrene
Gas gangrene causes severe pain in the infected area. Initially, the area is swollen and pale but eventually turns red, then bronze, and finally blackish green. The area is firm and tender to the touch. Large blisters often form. Gas bubbles may be visible within the blister or may be felt under the skin, usually after the infection progresses. Fluids draining from the wound smell rotten (putrid).
People quickly become feverish, sweaty, and very anxious. They may vomit. Heart rate and breathing often become rapid. In some people, the skin turns yellow, indicating jaundice. These effects are caused by toxins produced by the bacteria.
Typically, people remain alert until late in the illness, when dangerously low blood pressure (shock) and coma develop. Kidney failure and death rapidly follow.
Without treatment, death occurs in 100% of infected people. Even with treatment, many people die.
Diagnosis of Gas Gangrene
Examination and culture of fluids from the wound
Sometimes exploratory surgery or biopsy to obtain a tissue sample
Gas gangrene is suspected based on symptoms and results of a physical examination.
X-rays are taken to check for gas bubbles in muscle tissue, or computed tomography (CT) or magnetic resonance imaging (MRI) is done to check for areas of dead muscle tissue. These findings support the diagnosis. However, gas bubbles may also occur in other anaerobic infections.
Fluids from the wound are examined under a microscope to check for clostridia and are sent to a laboratory where bacteria, if present, can be grown (cultured) and tested. Cultures can confirm the presence of clostridia. However, not all people with clostridia have gas gangrene.
Confirmation of the diagnosis often requires exploratory surgery or removal of a tissue sample for examination under a microscope (biopsy) to check for characteristic changes in muscle.
Treatment of Gas Gangrene
Antibiotics
Surgery to remove all dead and infected tissue
If gas gangrene is suspected, treatment must begin immediately.
Treatment in a high-pressure oxygen (hyperbaric oxygen) chamber may also be helpful, but such chambers are not always readily available.
Prevention of Gas Gangrene
Skin injuries should be cleaned thoroughly. People should contact their doctor if the injured area enlarges and becomes swollen, hot, red, and tender because they may need antibiotics. People with diabetes and other disorders that weaken their immune system have an increased risk of developing injury-related infections and should be evaluated as early as possible.
Doctors do the following to prevent serious infections and gas gangrene in people who have wounds or who are undergoing surgery:
Clean wounds thoroughly
Remove foreign objects and dead tissue from wounds
Give antibiotics intravenously before, during, and after abdominal surgery to prevent infection
No vaccine can prevent clostridial infection.
