Necrotizing fasciitis

Necrotizing fasciitis

Necrotizing fasciitis (NF) or fasciitis necroticans, commonly known as "flesh-eating disease" or "flesh-eating bacteria", is a rare infection of the deeper layers of skin and subcutaneous tissues, easily spreading across the fascial plane within the subcutaneous tissue. Type I describes a polymicrobial infection, whereas Type II describes a monomicrobial infection. Many types of bacteria can cause necrotizing fasciitis (eg. Group A streptococcus, Staphylococcus aureus, Vibrio vulnificus, Clostridium perfringens, Bacteroides fragilis). Historically, Group A streptococcus (also known as Streptococcus pyogenes) made up most cases of Type II infections, although Staphylococcus aureus, including methicillin resistant S. aureus (MRSA), has also become an important cause of monomicrobial necrotizing fasciitis.

Symptoms

The infection begins locally, at a site of trauma, which may be severe (such as the result of surgery), minor, or even non-apparent. Patients usually complain of intense pain that may seem in excess given the external appearance of the skin. With progression of the disease, tissue becomes swollen, often within hours. Diarrhea and vomiting are common symptoms as well. Inflammation does not show signs right away if the bacteria are deep within the tissue. If they are not deep, signs of inflammation such as redness and swollen or hot skin show very quickly. Skin color may progress to violet and blisters may form, with subsequent necrosis (death) of the subcutaneous tissues. Patients with necrotizing fasciitis typically have a fever and appear very ill. Mortality rates have been noted as high as 73 percent. Without surgery and medical assistance, such as antibiotics, the infection will rapidly progress.

Pathophysiology

“Flesh-eating bacteria” is a misnomer, as the bacteria do not actually eat the tissue. They cause the destruction of skin and muscle by releasing toxins (virulence factors). These include streptococcal pyogenic exotoxins and other virulence factors. S. pyogenes produces an exotoxin known as a superantigen. This toxin is capable of activating T-cells non-specifically. This causes the over-production of cytokines.

Treatment

Patients are typically taken to surgery based on a high index of suspicion, determined by the patient's signs and symptoms. In necrotizing fasciitis, aggressive surgical debridement (removal of infected tissue) is always necessary. Diagnosis is confirmed by visual examination of the tissues, and by tissue samples sent for microscopic evaluation. Early medical treatment is often presumptive; thus, antibiotics should be started as soon as this condition is suspected. Initial treatment often includes a combination of intravenous antibiotics including penicillin, vancomycin and clindamycin. Cultures are taken to determine appropriate antibiotic coverage, and antibiotics may be changed when culture results are obtained. As in other maladies characterized by massive wounds or tissue destruction, hyperbaric oxygen treatment can be a valuable adjunctive therapy, but is not widely available. A recent study demonstrated excellent clinical outcomes from the use of topical negative pressure, (vacuum assisted closure wound therapy), a technology which is portable, and readily available. Amputation of the affected organ(s) may be necessary. Repeat explorations usually need to be done to remove additional necrotic tissue. Typically, this leaves a large open wound which often requires skin grafting. The associated systemic inflammatory response is usually profound, and most patients will require monitoring in an intensive care unit.

Other bacterial strains

In the last 5 years, a serious form of necrotizing fasciitis has been observed with increasing frequency. In these cases, the bacterium causing it was a strain of Staphylococcus aureus which is resistant to methicillin, the antibiotic used in the laboratory that determines the bacterium's sensitivity to flucloxacillin that would be used for treatment clinically (see Methicillin-resistant Staphylococcus aureus for details). Staphylococcus aureus, including its methicillin resistant forms, is now recognized as an important cause of necrotizing fasciitis.

Well-known victims

  • Alicia Cole, an actress, contracted hospital-acquired necrotizing fasciitis following a routine myomectomy to remove uterine fibroids. She withstood multiple debridement surgeries which removed most of her abdomen and left buttock. The disease was finally contained, sparing her from amputating her left leg.
  • David Walton, a leading economist in the UK and a member of the Bank of England’s Monetary Policy Committee which is responsible for setting interest rates, died of the disease within 24 hours of diagnosis on June 21, 2006.
  • Lucien Bouchard, former premier of Québec, Canada, who became infected in 1994 while leader of the federal official opposition Bloc Québécois party. He lost a leg to the illness.
  • Eric Allin Cornell, winner of the 2001 Nobel Prize in Physics, lost his left arm and shoulder to the disease in 2004.
  • Melvin Franklin, bass singer for The Temptations. Though Franklin’s condition was diagnosed early enough to prevent complete amputation of his arm, he died from other health complications soon afterward in 1995.
  • Lana Coc-Kroft, a New Zealand television celebrity, was infected after she stepped on a coral reef in Fiji in 2005.
  • Jan Peter Balkenende, Prime Minister of the Netherlands since 2002, was infected in 2004. He was in the hospital for several weeks, but recovered fully.
  • Alan Coren, British writer and satirist, announced in his Christmas 2006 column for The Times that his long absence as a columnist had been due to contracting the disease while on holiday in France.
  • Alexandru Marin, an experimental particle physicist, professor at MIT, Boston University and Harvard University, and researcher at CERN and JINR, died from the disease in 2005.
  • Tommy Kwok Chin, Detention Enforcement Officer, United States Department of Justice, Immigration and Naturalization Service, Detention and Deportation. In October 1999, Agent Chin died after contracting the bacteria while detaining 151 illegal Chinese immigrants on a remote island off the coast of Washington state.
  • Barbara Miller-Roy, the mother of former NHL superstar goaltender Patrick Roy contracted the disease in October 2005.
  • Matt Annis, nephew of retired professional wrestler Bret Hart.

See also

References

External links


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