Have you ever heard of a problem called necrotizing fasciitis (NF)? It’s an infection of the soft tissues — primarily the fascia or connective tissue. It’s a rare condition but one that can have deadly consequences. That’s why physicians must be trained to recognize it early and treat it aggressively.
In this review article, the diagnosis and treatment of necrotizing fasciitis are explained in detail. Risk factors, bacteria that can cause the problem, and specific diagnostic tests needed to identify the condition are discussed. Treatment by a multidisciplinary team is required for successful outcomes.
Necrotizing fasciitis (NF) is caused by a bacteria or fungus — there are over 25 different types known to cause NF. Some of the more common names you may recognize: e coli, staphylococcus, streptococcus, enterococcus. Many times there is more than one organism present contributing to the problem.
There are certain risk factors associated with NF. Most people who develop NF have suffered some type of skin or soft tissue injury or trauma. It can be something as minor as a skin abrasion or scratch, insect bite, or cut. Necrotizing fasciitis can be a complication of chickenpox in children.
Chronic skin ulcers, severe burns, open wounds from surgery or other infections can also put a person at increased risk for this condition. Other known risk factors include diabetes or other chronic diseases, intravenous drug abuse, and immunodeficiency. Immunodeficiency refers to a depressed immune system — usually from something like AIDS, organ transplantation, arthritis, or autoimmune diseases.
How would you know if you or someone you know has this condition? The first sign may be tenderness and/or redness of the skin followed by skin blisters. Fever, elevated heart rate, and low blood pressure develop as the soft tissue starts to die (necrotize).
Without successful treatment, the tissue may die because the blood vessels supplying nutrients to the skin are damaged. The condition can progress to the point that the patient can even die.
Diagnosis is based on several things: patient history, clinical presentation (signs and symptoms), and diagnostic tests. X-rays, CT scans, MRIs, ultrasound studies, and lab work may be ordered. These tests offer information that help the physician rule out other problems like cellulitis (a less severe skin infection) or skin abscess.
That sounds very simple but the diagnosis can actually be very tricky. At first, there are no substantial changes in vital signs. Advanced imaging like CT scans or MRIs can take time to schedule and cause a delay in diagnosis and thus in treatment.
Some research is being done to find a more reliable lab test that can quickly and accurately predict who might be developing necrotizing fasciitis. The first of these tests is called the Laboratory Risk Indicator for Necrotizing Fasciitis (LRINF). Early studies suggest this is a useful test but further validation is required before it can be adopted as a routine and reliable diagnostic tool.
Right now for the fastest and most accurate diagnosis, a skin biopsy is required. The surgeon can do this right in the office or at the patient’s bedside for those who are already hospitalized. Results are obtained almost immediately including the type of organisms present.
The identification of the underlying bacteria or fungi is important in prescribing the most effective antibiotic. Because there are often polymicrobes (many different types), a broad spectrum antibiotic may be needed to inactivate all types and prevent further spread of bacteria.
The bacteria produce several toxins, causing severe breakdown of tissue in multiple organs. At least 50 per cent of affected individuals experience toxic shock syndrome with hypotension (low blood pressure), nausea, vomiting, and delirium. There is often renal (kidney), lung, and liver compromise as well. Death rate is as high 65 per cent of all patients affected by NF.
Many patients need more than an antibiotic. This is especially true if the infected tissue has lost its blood supply and the drug can’t get to the area. That’s when surgery may be needed. The surgeon removes as much of the pus and necrotic (dead) tissue as possible. This procedure is called debridement. In many cases, the process has to be repeated several times (serial debridement).
Along with antibiotics and debridement, there’s a third key part to successful treatment. This is referred to as adjunctive therapy and can include oxygen therapy, intravenous immunoglobulin therapy, and nutritional support.
In summary, necrotizing fasciitis is a serious medical condition that can cause death of skin, soft tissue, and organs. Mortality (death of the patient) is also a possibility. Early, accurate diagnosis and immediate intervention with antibiotics, surgery, and supportive therapy are essential to preventing loss of limb and ensuring full recovery.