Necrotizing fasciitis

ANATOMY OR SYSTEM AFFECTED: Blood vessels, muscles, skin

DEFINITION: An invasive bacterial infection that occurs in the connective tissue between the skin and muscle known as the fascia, cutting off blood flow; it must be urgently treated surgically and, even in the best circumstances, has a high mortality rate

CAUSES: Bacterial infection

SYMPTOMS: Fever, inflammation, severe pain, blistering at site of infection, tissue death

DURATION: Acute

TREATMENTS: Emergency care, extensive surgical debridement, antibiotics

Causes and Symptoms

Although it had been identified in the past, in 1994 there were numerous headline newspaper reports describing a new “flesh-eating bacteria.” These articles detailed the devastating effect of seemingly minor wounds infected with streptococcal bacteria. Patients quickly become very sick, with a rapidly progressive downward course, even from trauma resulting in a deep muscle bruise, muscle strain, or “minor” cuts and scrapes.

In the case of nonpenetrating injuries, it is likely that the bacteria were already present in the blood and then seeded the site of damage. Most of these patients, however, did not recall any prior recent infection that may have made them susceptible. Penetrating injuries, where the normally protective barrier of the skin has been broken, were often minor and not originally treated as contaminated or infected. Other cases of necrotizing fasciitis are caused by surgical infections and bowel contamination. These cases are more rare and often found to contain other forms of bacteria as well, such as staphylococci or Escherichia coli (E. coli).

Patients with necrotizing fasciitis have fever, inflammation, severe pain, and blistering at the site of infection. If this cellulitis is not recognized and urgently treated, the infection will quickly spread in the layers of connective tissue just under the skin known as the fascia. As the bacteria multiply, they cause blood vessels supplying the skin to form clots and thus cut off blood flow to the skin. Without nutrients, oxygen, and the ability to remove waste products, the skin dies. Once this occurs, the nerves are destroyed, and the patient no longer experiences excruciating pain. The skin at this point appears to be “eaten away.” The possibility exists that the underlying muscle adjacent to the fascia will become infected. Thus, the potential for muscle death as well as skin death is of great concern, particularly if the infection begins in the arms, legs, abdomen, or back, as these areas have large muscle groups directly underlying the skin. In necrotizing fasciitis, the extremities and the area around the genitals and anus (perineum) are most commonly and extensively involved. Multiplication and movement of these streptococcal bacteria and their toxins into the bloodstream produces a shock-like state.

Treatment and Therapy

The patient with necrotizing fasciitis must be stabilized quickly in an intensive care unit, where fluids can be administered and heart and lung condition can be closely monitored. The only lifesaving treatment available is extensive surgical debridement to remove the necrotic (dead) tissue and slow the spread of the bacteria. Antibiotics such as penicillins, clindamycin, and gentamicin are given to help eradicate the pathogen. Because the infection spreads so rapidly, death often results even with heroic surgical and drug therapy unless the condition is diagnosed and treated early. Fortunately, these infections remain relatively rare. According to the Centers for Disease Control and Prevention, approximately 700 to 1150 cases have occurred annually in the United States since 2010. At the same time, by 2019, concern had increased among some experts in the medical community that climate change, which has been linked to increased seawater temperatures, could allow bacteria such as Vibrio vulnificus, which can cause necrotizing fasciitis, to thrive in waters previously too cold.

Bibliography

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