Medical Nightmare

05.14.12

Necrotizing Fasciitis: How ‘Flesh-Eating Bacteria’ Strike

A Georgia woman’s life-threatening battle with a gruesome infection has captivated the Web. Casey Schwartz on the science behind the rare affliction—and how it spreads.

The plight of Aimee Copeland has spread out over the Internet in horrifying detail, prompting ubiquitous Google searches. Is it true? Are flesh-eating bacteria even real?

Copeland, a blonde, 24-year-old graduate student, is supposed to be finishing up her master’s degree in eco psychology. Instead, she is in a hospital bed in Augusta, Ga., fighting for her life: a breathing tube down her throat, an amputated leg, and even more surgeries ahead. Copeland will likely lose her fingers. She was originally facing full hand amputation, but surgeons now think they will be able to preserve her palms, according to a blog post written on Saturday by Aimee’s father, Andy Copeland.

Andy Copeland has been documenting his daughter’s tragic medical drama online, since Aimee fell from a homemade zipline during an afternoon of swimming with friends in Georgia’s Little Tallapoosa River last Tuesday. Copeland reportedly gashed open her leg so deeply that doctors had to use 22 staples to seal the wound.

As it turned out, that wound was the least of Copeland’s problems. With each day that passed, she experienced worsening pain. Three days later, she was airlifted to Augusta and rushed to the emergency room at the Joseph M. Still Burn Center. Copeland, it turned out, had contracted a devastating infection called necrotizing fasciitis. It’s nothing short of a nightmare scenario you’d expect to see on an episode of Grey’s Anatomy—fodder for paranoia about all the contagions out there, lying in wait. Indeed, the extent of interest in Aimee’s case reveals the horrified fascination that the “flesh eating” condition tends to elicit.

“Necrotizing” denotes a substance that kills living tissue; necrotizing fasciitis is a bacterial infection that causes muscle, skin, and tissue death. The infection can be caused by several different types of bacteria, says Otto Yang, an infectious-diseases physician at UCLA’s David Geffen School of Medicine. “Almost any type of bacteria that can cause skin infections can cause this,” he says. “Staph. Streptococcus. And sometimes various mixtures of bacteria can get in there. “It’s one of the few true infectious-disease emergencies where an hour can make a huge difference.”

In Copeland’s case, several days passed between the moment of infection and the diagnosis of necrotizing fasciitis. The infection can be an extremely subtle clinical presentation because in its early stages there are often no clues visible on the surface—no redness, no swelling, no discharge from the wound—and frequently, no fever, which is typically the hallmark of an infection. The predominant symptom patients report is pain—and often, that is not enough to indicate to doctors that necrotizing fasciitis is at work.

“It can be a very subtle clinical presentation,” says William Schaffner, chair of preventive medicine at Vanderbilt University. “There’s a disconnect between the complaints of pain and the appearance of the wound. And that often delays the diagnosis.”

The most common bacteria responsible for necrotizing fasciitis is the Streptococcus pyogenes, known in lay terms as “flesh-eating bacteria,” an evocative name that does not paint a completely accurate picture. Copeland herself was infected by a bacterial strain called Aeromonas hydrophila, most often contracted in bodies of water.

“This is a bug that is essentially harmless except when it finds itself in the wrong place.”

Aeromonas happens to be a bug that has a particular capacity here that makes it a bad actor,” said Schaffner. “It has a distinctive capacity to switch its metabolism to one that does not require oxygen,” which means, Schaffner says, that even when deep inside a sealed wound with no exposure to oxygen, “it can do its damage; it can multiply and cause the destruction of the fascia in the muscle.”

“If I went swimming in the same water and dunked my head, nothing would happen to me. This is not a bug that can get on the surface and burrow in. Something has to give it access to those deep tissues and that was the problem here. She had that injury into which the water was splashed,” Schaffner said. “This is a bug that is essentially harmless except when it finds itself in the wrong place.”

Treatment for necrotizing fasciitis typically has three essential components: proper treatment of the wound, antibiotics for infection, and, if the infection advances, aggressive surgery to remove all affected tissue. This is where things can get tricky, says Schaffner.

“The difficulty here is that even aggressive surgeons are almost always fooled, because they will take out everything that appears not viable—everything that is dead, diseased tissue—but the infection is already microscopically working beyond that. So you have to be a very aggressive surgeon to cut out what appears to be viable tissue at the wound’s margins. This gets you against what every surgeon is otherwise taught: preserve the viable tissue. So you have to get very aggressive. And it’s not unusual for surgeons to have to go back a second or third time to keep up with and get ahead of the infection.”