What is Necrotizing Fasciitis?
Necrotizing fasciitis is a type of serious skin and soft tissue infection that causes the skin and tissues beneath it to die. This infection usually moves along the layers of tissue that cover muscles, which don’t have a good blood supply. As a result, the tissues on the surface might appear okay at first, which can delay the detection and treatment of the infection. This disease can quickly spread, infecting the tissue layers surrounding the muscles and leading to secondary infections of the skin, underlying soft tissues, and muscles.
Necrotizing fasciitis can happen after surgery, invasive procedures, or even simple processes like having blood drawn for tests. The bacteria causing this infection are generally diverse, but they do produce gas, as you can see in the image titled “Necrotizing Fasciitis”.
What Causes Necrotizing Fasciitis?
Necrotizing fasciitis, a skin infection that often progresses rapidly over a few days, usually occurs when bacteria enter the body through a break in the skin. About 80% of all cases start this way. The most common bacteria causing this infection come from the Staphylococcus aureus and Streptococci groups, which are types of bacteria often found on the skin.
Some cases can involve multiple types of bacteria, including those resistant to oxygen (known as anaerobic bacteria).
Most of the patients diagnosed with this condition have a history of diabetes or alcoholism. This condition is also more common in people with liver cirrhosis (a long-term liver damage). Understanding one’s health history can help in early detection and treatment of this severe skin infection.
Risk Factors and Frequency for Necrotizing Fasciitis
Necrotizing fasciitis, a kind of severe skin infection, impacts approximately 0.4 out of every 100,000 people each year in the United States. However, in certain parts of the world, it can affect as many as one in every 100,000 people.
of skin and fascia.
Signs and Symptoms of Necrotizing Fasciitis
Necrotizing infections are a serious type of tissue-infecting diseases that usually cause severe pain disproportionate to the symptoms presented initially, and often show signs related to sepsis, a life-threatening response to infection.
There are several physical symptoms that hint at the presence of necrotizing soft tissue infections which include:
- Pain when touched, expanding past the red zone or skin inflammation
- An unusual crackling sensation under the skin, medically known as crepitus, and skin inflammation
- Formation of fluid-filled blisters or bullae
- Patches of skin discoloration or surface bruising known as ecchymotic changes
- Abnormal sensations like numbness or tingling, either referred to as dysesthesia or paresthesia
- In some instances, there may also be an absence of feeling in certain areas due to damage to the nerves.
The progression of the infection can happen fast, often within hours, hence in the presence of intense pain, one should be highly suspected of having necrotizing fasciitis, a severe type of necrotizing infection.
Testing for Necrotizing Fasciitis
If you have a skin or tissue infection that is spreading quickly, it’s important that it’s treated right away. This is because it can be hard to tell if the infection is just affecting the surface of your skin or if it’s a severe infection that’s destroying the tissues beneath your skin.
Doctors can often use a scoring system called the Laboratory Risk Indicator for Necrotizing Infection (LRINEC) Score. This score was made to help differentiate between severe soft tissue infections and other types of skin and tissue infections. The score is calculated based on six factors including the levels of C-reactive protein, white blood cell count, hemoglobin, sodium, creatinine, and glucose in your blood. Each test is given a score and the total score is used to determine the likelihood of a necrotizing infection, a type of severe skin or tissue infection.
A score of six has a 92% likelihood of predicting a necrotizing infection correctly, while being able to predict no infection 96% of the cases. If the score is eight or more, there’s a 75% chance of having a severe infection.
Diagnosing skin and tissue infections is primarily done using clinical observation and assessment. However, medical imaging can provide more information when the diagnosis is unclear. A type of X-ray, called a plain film, may show changes like thickness and darkness of the skin tissue, similar to cellulitis, a common skin infection. Computed tomography (CT) scans are more sensitive than X-ray in identifying severe skin or tissue infections because they can show more detailed images. Sometimes, a doctor may choose to examine the area of infection more closely by probing it under local anesthesia. They might also take a sample of the infected area, to examine it under a microscope.
Doctors can also use a tool called a B-mode color Doppler ultrasound. This tool can help them identify severe skin or tissue infections early on. It’s crucial to remember, however, that no test should delay the needed surgical treatment.
Treatment Options for Necrotizing Fasciitis
Patients with severe illnesses are immediately moved to the intensive care unit for close monitoring and treatment. As sepsis, a potentially life-threatening infection, can cause dangerously low blood pressure and fluid leakage from blood vessels, these patients require immediate fluid resuscitation and medications (inotropes) to help maintain blood pressure. They’re generally not allowed to eat or drink until the surgeon evaluates them. Once surgery is done and the patient’s body is stable, nutrition through a feeding tube can be initiated to help counterbalance protein loss due to the body’s response to severe illness.
The key steps in the treatment of skin and soft-tissue infections include:
- Early diagnosis and understanding the severity of the tissue infections.
- Starting early broad-spectrum antibacterial treatment, which means using an antibiotic or combination of antibiotics that can kill a wide range of bacteria.
- Appropriate management of the infection source. This often involves surgical intervention for draining pus-filled abscesses or removing infected tissue in severe soft tissue infections.
- Identifying the bacteria responsible for the infection and tailoring the antibiotic treatment accordingly.
In treating a serious skin infection called necrotizing fasciitis, medications like Imipenem, Piperacillin/Tazobactam, and Meropenem, often combined with other antibiotics, are commonly used. But the specifics of the antibiotic regime can vary depending on individual patient factors, such as allergies or previous antibiotic exposure.
Surgery is a critical part of treatment in necrotizing fasciitis, and should not be delayed. The aim of the surgery is to remove any dead or infected tissue as quickly as possible. The surgery area is typically left open and treated with regular wet dressing changes. Sometimes, multiple surgeries may be needed to remove all the infected tissue. This process often results in a speedy recovery once the necrotic tissue and pus are removed. Patients are generally kept in the intensive care unit and may remain on a ventilator (breathing support) for some time after surgery.
After complete removal of the infected tissue and with evidence of new tissue growth, a plastic surgeon may be consulted to reconstruct the affected area. Often, direct wound closure isn’t possible, so the surgeon needs to reconstruct tissue or close the wound using a muscle flap. If there isn’t enough available skin for a graft, artificial skin may be used.
Hyperbaric oxygen therapy (treatment with 100% oxygen in a pressurized chamber) is another treatment sometimes used in addition to surgery when treating necrotizing fasciitis. However, it often poses logistical challenges due to the patient’s critical condition and the need for various medical equipment. While it may assist in treating smaller wounds, there’s no solid evidence to suggest it improves healing or survival rates in larger wounds. It’s important to remember that this method doesn’t replace surgical treatment, but can complement it.
What else can Necrotizing Fasciitis be?
Here are some conditions that might also need to be considered when diagnosing certain ailments:
- Cellulitis (skin infection)
- Epididymitis (inflammation of the tube at the back of the testicle that stores and carries sperm)
- Gas gangrene (a bacterial infection that produces gas in tissue)
- Orchitis (inflammation of one or both of the testicles)
- Testicular torsion (a painful condition caused by the twisting of the spermatic cord, which causes a loss of blood flow to the testicle)
- Toxic shock syndrome (a severe and life-threatening illness caused by bacterial toxins)
What to expect with Necrotizing Fasciitis
Necrotizing fasciitis is a severe infection that can be life-threatening, with death rates varying between 20% and 80%. Certain factors can worsen the prognosis (or health outcomes). These include certain types of streptococcal bacteria, advanced age, uncontrolled diabetes, a suppressed immune system, and delayed surgery.
Even when individuals survive this infection, they often face a long recovery period and significant functional deficits, meaning they may struggle with everyday tasks.
Possible Complications When Diagnosed with Necrotizing Fasciitis
- Failure of multiple organs
- Sepsis leading to a drastic drop in blood pressure
- Loss of a limb
- Intense scarring
- A severe and sudden systemic infection
- Possible death
