Necrotizing fasciitis is a rapidly progressing type of infection that mainly affects the subcutaneous connective tissue planes or, 'fascia,' where it can quickly spread to involve adjacent soft tissues and lead to widespread tissue death or, 'necrosis.'
Alternative Names: Necrotizing fasciitis; Fasciitis necrotizing; Flesh eating bacteria; Soft tissue gangrene. Necrotizing Fasciitis is a serious bacterial infection that spreads rapidly and destroys the body's soft tissue. Commonly called a "flesh-eating infection" by the media, this rare disease can be caused by more than one type of bacteria. These include group A Streptococcus (group A strep), Klebsiella, Clostridium, E. coli, Staphylococcus aureus, and Aeromonas hydrophila, among others. Group A strep is considered the most common cause of necrotizing fasciitis.
A number of different types of flesh-eating bacteria can cause this life-threatening condition, which may affect healthy people as well as people who experience underlying medical issues. While it is rarely encountered, there has been an increase in the incidence of necrotizing fasciitis over the last few decades. It is estimated that there are between 500 and 1,000 people who experience necrotizing fasciitis in America every year. Early identification and treatment are critical to manage the potentially devastating consequences of this true medical emergency.
While necrotizing fasciitis has most likely existed for several centuries, several detailed descriptions of this condition were reported in the 1800's. In the year 1952, Dr. B. Wilson first used the term, 'necrotizing fasciitis,' to describe the condition. Other terms have been used to describe it including:
When necrotizing fasciitis affects a person's genital area it is many times referred to as, 'Fournier gangrene.'
Necrotizing fasciitis is caused by bacteria in the majority of instances, although fungi may also lead to the condition. A number of instances of necrotizing fasciitis are caused by group A beta-hemolytic streptococci, either individually or in conjunction with additional bacterial pathogens. Group A streptococcus is the same bacteria responsible for, 'strep throat,' impetigo, and rheumatic fever.
In more recent years there has been a surge of instances of necrotizing fasciitis cause by, 'community-acquired methicillin-resistant Staphylococcus aureus (MRSA)', many times occurring in people who are intravenous drug abusers. The majority of instances of necrotizing fasciitis are, 'polymicrobial,' and involve both aerobic and anaerobic bacteria. Other bacterial organisms that may be isolated in instances of necrotizing fasciitis include:
Other types of bacterial organisms may be isolated as well. A rarely encountered bacterium in people, 'Aeromonas hydrophila,' was recently implicated in an instance of necrotizing fasciitis in a young woman who cut her leg in a zip line accident. The organism, usually found in freshwater and brackish water in climates that are warmer, commonly causes infections in amphibians and fish.
In many instances of necrotizing fasciitis there is a history of previous trauma such as a scrape, cut, insect bite, needle puncture wound, or burn. The lesions might initially appear to be minor or trivial. Surgical incision sites and various surgical procedures might also serve as sources of infection. In many instances; however, there is no clear source of infection or portal of entry to explain the cause.
Once the bacterial pathogen gains entry into a person's body, the infection may spread from their subcutaneous tissues and involve deeper facial planes. Progressive spread of infection ensues and may sometimes involve adjacent soft tissues including skin, fat, and muscle. Various bacterial enzymes and toxins lead to vascular occlusion and result in tissue hypoxia and ultimately - tissue necrosis. In many instances, the tissue conditions allow anaerobic bacteria to proliferate too, allowing for the progressive spread of infection and continued destruction of a person's tissues.
People with underlying medical issues and a weakened immune system are also at increased risk of developing necrotizing fasciitis. A number of medical conditions to include:
Are many times present in people who develop necrotizing fasciitis, as are people undergoing chemotherapy and those who are taking corticosteroids. Intravenous drug abusers and alcoholics are also at increased risk. Many instances of necrotizing fasciitis; however, also happen in otherwise healthy people with no predisposing factors.
The signs and symptoms of necrotizing fasciitis vary with the extent and progression of the disease. Necrotizing fasciitis many times affects a person's extremities or their genital area, although any area of their body may be involved. Early in the course of the disease, people with necrotizing fasciitis might appear well and may not demonstrate any superficial visible signs of any underlying infection. Some people might initially complain of soreness or pain similar to that of a pulled muscle. As the infection rapidly spreads, the signs and symptoms of severe illness become much more apparent.
Necrotizing fasciitis usually appears as an area of localized redness, swelling, warmth and pain - often times resembling a superficial skin infection. Often times the tenderness and pain people experience is out of proportion to the visible findings on their skin. They may experience chills and a fever. Over the course of hours to days, the redness of their skin quickly spreads and their skin might become purplish, dusky, or dark in color.
Overlying black scabs, blisters, hardening of the person's skin, skin breakdown, as well as wound drainage can develop. At times a fine crackling sensation might be felt under the person's skin, signifying gas within the person's tissues. The severe tenderness and pain the person experiences might later diminish due to subsequent nerve damage, leading to localized anesthesia of the affected area. If left untreated, continued spread of the infection and widespread bodily involvement happens frequently leading to sepsis and often times - death. Additional symptoms associated with necrotizing fasciitis can include nausea, vomiting, malaise, dizziness, weakness, and confusion.
Prompt identification and treatment of necrotizing fasciitis is crucial in order to improve the likelihood of a favorable outcome. Due to the rapid progression of the condition, a high index of suspicion and early detection are needed to initiate emergency treatment immediately. People with underlying medical issues or a weakened immune system need to be particularly vigilant. Seek medical attention if any of the following signs or symptoms develop:
If a person has been previously evaluated by a health care professional and there is progression of the symptoms described above, or if the person fails to improve, prompt re-evaluation is needed.
A diagnosis of necrotizing fasciitis is many times presumptively made initially based upon a person's history and physical examination findings. While there are a number of laboratory tests and imaging studies that might help in making the diagnosis, immediate results may not be readily available. Due to this, a high index of suspicion in any person with signs or symptoms suggestive of necrotizing fasciitis should prompt immediate consultation with a surgeon in order to expedite treatment.
Tissue Culture: Tissue culture, biopsy, and Gram stain results may help definitively identify the organism or organisms responsible for the infection and help to guide appropriate antibiotic therapy.
Laboratory testing: Laboratory testing will include various blood tests such as a, 'complete blood count (CBC),' which might reveal an elevated white blood cell count (WBC). Electrolyte panels, blood cultures, and other blood tests are also usually obtained. However; the results of these blood tests cannot be solely relied upon to make an immediate diagnosis.
Imaging studies: Imaging studies such as MRI, CT scans, and ultrasound have all been used with success to identify instances of necrotizing fasciitis. They might be used when signs are equivocal, or the diagnosis is in doubt. The modalities might assist in identifying areas of fluid collections, inflammation and gas within a person's soft tissues, in addition to helping delineate the extent of the infection. While occasionally plain x-rays may demonstrate gas in soft tissue, they are considered less useful and of little value. Obtaining imaging studies should not delay definitive treatment in those instances highly suggestive of necrotizing fasciitis.
Necrotizing fasciitis is an emergency condition - it is not something that can be managed at home. People with necrotizing fasciitis need to be admitted to a hospital, appropriate IV antibiotics, surgical debridement, as well as close observation in an intensive-care unit.
When a diagnosis of necrotizing fasciitis is highly suspected or confirmed, immediate measures have to be taken to initiate treatment and rapidly intervene in order to reduce morbidity and mortality. The medical treatment of necrotizing fasciitis main involves the administration of antibiotics, with hyperbaric oxygen therapy and intravenous immunoglobulin administration being used less commonly. The definitive treatment for necrotizing fasciitis ultimately requires surgical intervention. Initial management includes:
Some people with sepsis might require the administration of intravenous medications to increase their blood pressure or the insertion of a breathing tube in instances of severe illness or respiratory compromise. Close monitoring and supportive care in an intensive-care unit is a must.
Broad-spectrum antibiotics should be started promptly. As the organisms that are responsible may not be initially known, antibiotics should include coverage for a wide array of organisms to include aerobic gram-positive and gram-negative bacteria, as well as anaerobes. Consideration for infection caused by MRSA should also be taken into account and consultation with an infectious disease specialist might be helpful. There are various antibiotic regimens available which might involve monotherapy or multi-drug regimens. Commonly recommended antibiotics include:
The majority of clinicians treat with more than one IV antibiotic because bacteria that cause necrotizing fasciitis are many times resistant to more than one antibiotic and some infections are caused by more than one bacterial genus. Antibiotic coverage can be adjusted after culture results identify the causative organism or organisms and antibiotic sensitivity results become available. Antibiotic sensitivity testing is required to adequately treat MRSA and the new NDM-1 antibiotic resistant strains of bacteria.
Intravenous Immunoglobulin (IVIG): Some investigators feel that IVIG might be a useful adjunct treatment in instances of streptococcal necrotizing fasciitis because it has been shown to successfully neutralize streptococcal exotoxins in Streptococcal toxic shock syndrome.
Hyperbaric Oxygen Therapy: Hyperbaric oxygen therapy (HBO) delivers highly concentrated oxygen to people in a specialized chamber, increasing tissue oxygenation and inhibiting anaerobic bacteria while promoting tissue healing. Some investigators feel that HBO reduces mortality in some people when used along with an aggressive treatment regiment that includes antibiotics and surgery. HBO is not widely available.
Quick surgical debridement of infected tissue is the cornerstone of treatment in instances of necrotizing fasciitis. Early detection and prompt surgical intervention have been shown to decrease morbidity and mortality, highlighting the importance of early surgical involvement and consultation. Extensive surgical debridement of all necrotic tissue is a requirement. Wide and deep incisions might be necessary to excise all infected tissue until healthy tissue is visualized.
Repeated surgical debridement is many times necessary within the ensuing hours to days after the initial surgical intervention because the progression of the disease might be sudden, severe and unrelenting. Sepsis might lead to other infection sites and those areas may need surgical intervention as well, resulting in some people requiring multiple amputations. In some instances, despite repeated surgical debridement, a life-saving amputation might be necessary if the necrosis is too widespread and the imminent risk of overwhelming sepsis and death is believed to be present. Management of necrotizing fasciitis usually requires a multidisciplinary approach involving surgeons, infectious-disease specialists, pathologists, critical-care specialists, as well as others to provide comprehensive care.
People who survive necrotizing fasciitis often require follow-up with a number of specialists depending upon the complications they experience during their hospital stay and the results. A number of people require skin grafting or reconstructive surgery, as well as physical therapy and rehabilitation. Psychological intervention is needed at times for people who might experience anxiety, depression, or other psychological repercussions.
The prognosis for people with necrotizing fasciitis depends on a number of factors to include the person's age, the causative organism or organisms, any underlying medical issues the person experiences, the location and extent of the infection, and the time course of diagnosis and initiation of treatment. Early diagnosis and aggressive surgical and medical treatment are the most important factors in determining a person's outcome.
Necrotizing fasciitis is a life and limb-threatening condition that has a poor prognosis if it remains untreated. Complications and potential results can include limb loss, disfigurement, scarring, and disability. Many people develop sepsis, multisystem organ failure, and death. Combined morbidity and mortality rates associated with necrotizing fasciitis have been reported to be between 70 and 80%. Mortality rates might range anywhere between 6 and 76%
The National Nectrotizing Fasciitis Foundation - www.nnff.org
Necrotizing Fasciitis - www.cdc.gov/features/NecrotizingFasciitis/
What is necrotizing fasciitis - www.webmd.com/a-to-z-guides/necrotizing-fasciitis-flesh-eating-bacteria-topic-overview