Necrotizing fasciitis

• 1. Introduction

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  Necrotizing fasciitis can turn a small break in the skin into a surgical emergency within hours. Doctors abbreviate it as NF, and newspapers call it flesh-eating disease. The infection kills the body's soft tissue. Even with high-quality treatment, between 25 and 35 percent of patients die. Its victims have ranged from ordinary patients to famous names.

  Why does a disease this deadly so often look like a simple skin infection at first? What actually destroys the tissue? And why do surgeons sometimes reach for the scalpel before they are certain of the diagnosis? To answer these questions, we begin with the name itself, which misleads in more than one way.

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• 2. A Misleading Nickname

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  Despite the grisly label flesh-eating disease, bacteria do not eat human tissue at all. They release toxins, and the toxins kill the tissue. Bacterial infection is by far the most common cause. Typically the germs slip in through a break in the skin, such as a cut or a burn.

  The phrase flesh-eating virus is wrong, yet it circulates anyway. Two other conditions, peripheral symmetrical gangrene and acute rhabdomyolysis, are sometimes confused with NF. All three have occasionally been called by that same mistaken virus label.

  Fear of catching the illness from a patient is also misplaced. The disease does not usually spread between people. The danger lies in what happens inside one body.

  The medical story behind the name, however, reaches back to the fifth century B.C.

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• 3. Naming a Killer

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  In the fifth century B.C., Hippocrates became the first person to describe necrotizing soft tissue infections. His account reads: "Erysipelas all over the body while the cause was only a trivial accident. Bones, flesh, and sinew (cord, tendon, or nerve) would fall off from the body, and there were many deaths".

  In the 18th century, the British surgeon Leonard Gillespie and the British physicians Gilbert Blaine and Thomas Trotter described these infections in English. No standard name existed. Writers called them severe ulcers, gangrene, erysipelas or cellulitis. Later, the phrase hospital gangrene became the more common choice.

  In 1871, Joseph Jones, a surgeon in the Confederate States Army, reported 2,642 cases of hospital gangrene. The mortality rate among them was 46 percent.

  In 1883, Dr Jean-Alfred Fournier described necrotizing infections of the perineum and scrotum. That condition now carries his name, Fournier gangrene. The term necrotizing fasciitis itself was coined by Dr. Bob Wilson in 1952. Since then, its definition has broadened to cover infections of fascia and soft tissue.

  Sensationalistic news media preferred another phrase, galloping gangrene, whenever outbreaks made headlines. The medical community disfavored it. Modern doctors instead sort cases by the bacteria responsible, and that system has four categories.

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• 4. Four Bacterial Types

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  In 1977, Giuliano and his colleagues first described a way to sort the infection into four groups, based on the organisms involved.

  Type I is the most common, accounting for 70 to 80 percent of cases. It is polymicrobial, meaning a mixture of bacteria works together, usually in the abdominal or groin areas. The mixture can include Staphylococcus aureus, Streptococcus pyogenes and Enterococci. It can also include Escherichia coli, Pseudomonas aeruginosa, Klebsiella, Bacteroides and Prevotella. Clostridium species such as Clostridium perfringens, Clostridium septicum and Clostridium sordellii may join in as well.

  Group A Streptococcus, which is S. pyogenes, is the bacterium most often found in these mixed infections. S. aureus comes second. If S. pyogenes or S. aureus is the sole cause, the case counts as type II instead.

  Clostridia make up 10 percent of type I infections. They typically cause a form known as gas gangrene, or myonecrosis. Gram-negative bacteria and anaerobes such as Clostridia are more often involved in Fournier gangrene, a subtype of type I that affects the groin and perianal areas.

  Type II covers 20 to 30 percent of cases and mainly strikes the arms and legs. S. pyogenes is responsible, alone or alongside staphylococcal bacteria. Methicillin-resistant Staphylococcus aureus, called MRSA, appears in up to a third of type II infections. Either organism can progress rapidly and end in shock. Type II more commonly affects young, healthy adults who have a history of injury.

  Type III involves Vibrio vulnificus, a bacterium found in saltwater. It occasionally causes NF after entering through a break in the skin. One in three patients with a V. vulnificus infection develops necrotizing fasciitis. The disease progresses much like type II, though sometimes with few visible skin changes.

  Type IV accounts for less than 1 percent of cases. It is mostly caused by the fungus Candida albicans. Age and immunodeficiency are its risk factors.

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• 5. Who Is Vulnerable

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  Diabetes mellitus, obesity and immunodeficiency mark the typical victim, who is usually older. Other documented risk factors include any trauma or laceration, injection drug use and recent surgery. Injuries to mucous membranes, such as hemorrhoids and rectal fissures, also count. So do peripheral artery disease, cancer, alcohol use disorder, and pregnancy or recent childbirth. For reasons that remain unclear, the infection can also strike healthy people with no medical history or injury.

  NSAIDs, a common class of painkillers, may raise the rate of necrotizing infections by weakening the immune response. They inhibit prostaglandins, the chemicals responsible for fever, inflammation and pain. In theory, they also stop white blood cells from migrating to infected areas, which raises the risk of soft-tissue infection.

  Abscesses and ulcers in the skin can complicate NF. A small percentage of people develop it when bacteria from streptococcal pharyngitis spread through the blood. For infections of the perineum and genitals, the contributing factors may include a urinary tract infection, renal stones or a Bartholin gland abscess.

  Good wound care and handwashing reduce the risk. Whether people with weakened immune systems benefit from antibiotics after exposure is unclear. Such a regimen generally means 250 mg of penicillin four times daily for 10 days.

  In the United States, NF occurs in about 4 people per million each year, which amounts to roughly 1,000 cases annually. Western Europe sees about 1 case per 100,000 people. The rates in the United States have been rising. That could reflect greater awareness and reporting, or it could reflect increasing antibiotic resistance. Both sexes are affected equally. The disease is more common among older people and rare in children.

  It can strike any part of the body, though the extremities, perineum and genitals are the usual sites. A small fraction of cases arise in the head and neck, chest, and abdomen.

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• 6. Hard to Detect

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  A fever above 102 degrees Fahrenheit, or 39 Celsius, is among the early warnings. Others include redness, swelling and excessive pain. Induration, meaning hardening of the skin and soft tissue, is another. Patients may also feel fatigue and muscle pains. A surgical site may leak large amounts of smelly pus and discharge.

  The trouble is that these early changes resemble cellulitis or an abscess. The redness and swelling usually blend into the surrounding healthy tissue, and the skin may look shiny and tense. That makes early diagnosis difficult.

  Bullae, which are blisters, can appear later. So can crepitus, meaning gas that can be felt in the tissues. Reduced or absent sensation over the affected skin is another late sign. Bruising may progress to skin death as clotting blood vessels turn the skin from red to purple and black. These signs are present in less than half of cases. Rapid progression to shock despite antibiotics is a further warning.

  Cancer, corticosteroid use, radiotherapy, chemotherapy, HIV/AIDS, and a history of organ or bone marrow transplant can all mask the typical symptoms. People with weakened immune systems are twice as likely to die from necrotizing infections. Doctors are therefore told to keep a higher level of suspicion in this group.

  When doubt remains, a surgeon can make a 2-cm incision in the affected tissue under local anesthesia. If a finger easily separates the tissue along the fascia, the finger test is positive. That confirms the diagnosis and calls for extensive debridement. Surgical exploration followed by a tissue biopsy is the gold standard, because no lab test or scan can rule the disease out.

  A white blood cell count above 15,000 cells per cubic millimeter, together with a serum sodium level below 135 mmol/L, predicts NF in 90 percent of cases. If the values fall short, there is a 99 percent chance the patient does not have it.

  In 2004, Wong and colleagues developed the laboratory risk indicator for necrotizing fasciitis, or LRINEC, now the most common scoring system. It is meant for people with severe cellulitis or abscesses. It uses six lab values: C-reactive protein, total white blood cell count, hemoglobin, sodium, creatinine and blood glucose. A score of 6 or more indicates a 50-75 percent probability of NF. A score of 8 or more means over 75 percent. Patients scoring 6 or more may also face a higher rate of death and amputation.

  The system is yet to be validated. A score of 6 or more detects only 70 percent of NF cases, and a score of 8 or more performs even worse. Other inflammatory conditions can produce false positives, so the score must be read with caution.

  Imaging is a trade-off against time. Because treatment must be rapid, the delay of a scan is a major concern, and imaging may be skipped when the signs are already clear. Often, though, the vague early symptoms make a scan useful.

  Computed tomography, or CT, is the most convenient tool when available, thanks to its speed and resolution. It detects about 80 percent of cases. It may show fascial thickening, edema or abscess formation. It spots gas in the tissues better than MRI, but NF often shows no gas on imaging. Its use may be limited in pregnant patients and in patients with kidney issues.

  Magnetic resonance imaging, or MRI, detects about 93 percent of cases and shows soft tissue better than CT. It is especially good at finding fluid in the deep fascia, which helps tell NF from cellulitis. Fluid in the deep fascia, or thickening and enhancement with contrast, should raise strong suspicion. MRI is much slower than CT and less widely available. Kidney problems can limit its use too.

  Point-of-care ultrasound, or POCUS, can help when CT and MRI are unavailable. It can also rule out look-alikes of early NF, including deep vein thrombosis, superficial abscesses and venous stasis. Its findings are summed up by the mnemonic STAFF: Subcutaneous irregularity or Thickening, Air, and Fascial Fluid. An official ultrasound diagnosis requires both diffuse subcutaneous thickening and fascial fluid of more than 2 mm. Gas may produce what is called dirty acoustic shadowing. Results depend heavily on the operator, and it is still unclear whether POCUS speeds up surgery.

  Plain X-rays can detect subcutaneous emphysema, which is gas under the skin and strongly suggests necrotizing changes. Air is usually a late finding, so radiography is not recommended for the initial diagnosis. It may still identify the source of infection, such as foreign bodies or fractures, and so guide the treatment that follows.

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• 7. The Surgical Race

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  Antibiotics begin the moment doctors suspect the disease, but surgery removes the dead tissue. Delays in operating are associated with a much higher risk of death, so the condition is treated as a surgical emergency. The choice of antibiotics may change once tissue cultures return. Patients with unstable vital signs or low urine output need extra support.

  Debridement, the cutting away of affected tissue, begins as soon as the diagnosis is made. The same area may need to be debrided several times, usually once every 12 to 36 hours. Large sections of tissue and muscle may have to be removed to stop the spread. When the infection is too severe, amputation may be needed.

  En bloc debridement is the approach most commonly used for necrotizing soft tissue infections, abbreviated NSTIs. It cuts away the skin over every diseased area. The price is heavier scarring and a possibly lower quality of life after surgery. A newer method, skin-sparing debridement, removes the underlying tissue and sources of infection but keeps skin that is not clearly dead. More studies are needed to learn whether it speeds healing.

  Afterward, wounds are generally packed with wet-to-dry dressings and left open to heal. Vacuum-sealing drainage may help, especially in Fournier gangrene. In the perineum, excretory products make wound care difficult. Regular dressing changes with a fecal management system help keep the area clean. Sometimes a colostomy is needed to divert waste away from the wound.

  The first antibiotics are empiric, meaning they are chosen before cultures identify the culprit. They are also broad-spectrum, covering gram-positive bacteria including MRSA, gram-negative bacteria and anaerobes. A combination of clindamycin, daptomycin, IV vancomycin and gentamicin is often used. Gram-negative coverage may involve fluoroquinolones, piperacillin/tazobactam or carbapenems.

  Despite many studies, there is no consensus on how long antibiotics should continue. Generally they last until surgeons decide no more debridement is needed and the patient shows no systemic signs of infection in the clinic or the lab.

  Hyperbaric oxygen is meant, in theory, to reduce local inflammation and strengthen the immune response. Its effect on patients remains unclear. Intravenous immunoglobulin, or IVIG, is intended to counter the exotoxins released in S. pyogenes toxic shock syndrome. Studies have found no effect on mortality, and serious adverse effects are possible. Supportive therapy is always given when appropriate. It includes intravenous hydration, wound care, anticoagulants to prevent thromboembolic events, pain control and vasopressors.

  Reltecimod, also called AB103, is a newer drug that binds to the CD28 T-cell receptor and so softens the effects of bacterial toxins. Studies suggest it may reduce the severity of organ failure in NF patients. Other studies found no difference in mortality.

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• 8. Famous Survivors

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  In 1994, Lucien Bouchard lost a leg to the illness while leading the Bloc Québécois, then the official opposition in Canada's federal parliament. He later became premier of Québec. The same year, a cluster of cases in Gloucestershire, in the west of England, drew heavy attention. Of five confirmed infections and one probable, two ended in death. The first two patients acquired Streptococcus pyogenes during surgery, and the other four were community-acquired. Newspapers ran lurid headlines such as "Flesh Eating Bug Ate My Face".

  Several prominent people have lost limbs. In 2004, Eric Allin Cornell, winner of the 2001 Nobel Prize in Physics, lost his left arm and shoulder. In 2009, the journalist and historian R. W. Johnson injured his foot while swimming in March, and his leg was later amputated above the knee. In 2014, the actor Ricky Bartlett lost both legs after a trip to Wyoming and South Dakota. In 2015, the Estonian politician Edgar Savisaar had his right leg amputated after a trip to Thailand.

  Others endured repeated operations. In 1997, Jeff Moorad, a former agent and partial owner of the San Diego Padres and Arizona Diamondbacks, had seven surgeries in a little more than a week. He recovered fully. In 2004, the comedian Don Rickles, known for insult comedy, had six operations on his left leg. He recovered, but the condition confined him in his later years to performing from a chair.

  Some did not survive. In 2005, Alexandru Marin, an experimental particle physicist who had worked at MIT, Boston University, Harvard University, CERN and JINR, died of the disease. Slayer guitarist Jeff Hanneman contracted it in 2011. He died of liver failure on the 2nd of May 2013, and many speculated that the infection was the cause. On the 9th of May 2013, the official cause was announced as alcohol-related cirrhosis. Hanneman and his family had apparently not known the extent of the condition until shortly before his death.

  Writers and musicians turned the ordeal into material. The British satirist Alan Coren revealed in a Christmas column for The Times in 2006 that he had caught the disease on holiday in France, which explained his long absence. In 2011, the science fiction author Peter Watts wrote on his blog: "I'm told I was a few hours away from being dead... If there was ever a disease fit for a science-fiction writer, flesh-eating disease has got to be it. This... spread across my leg as fast as a Star Trek space disease in time-lapse." In 2014, Daniel Gildenlöw of the Swedish band Pain of Salvation spent several months in hospital after the infection reached his back. He later wrote a concept album about the hospitalization, In the Passing Light of Day.

  The disease has also reached younger people and athletes. In 2018, the American football quarterback Alex Smith suffered an open compound fracture of his lower leg during a game, and it became infected. He narrowly avoided amputation and returned to professional football in October 2020. His recovery is the subject of the ESPN documentary E60 Presents: Project 11. In 2019, the rapper OG Maco contracted NF after an untreated rash. British actress Georgie Henley revealed in 2022 that she caught it in 2013, several weeks after starting at Cambridge University, and that it had almost killed her.

  In 2024, the Irish actor Barry Keoghan revealed that he had contracted NF in 2021, shortly before filming The Banshees of Inisherin. He said he nearly had his arm amputated.

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