A severe type of tissue infection that can involve the skin, subcutaneous fat , the muscle sheath (fascia), and the muscle. It causes gangrenous changes, tissue death, systemic disease, and frequently death.
Alternative Names
Necrotizing fasciitis; Fasciitis - necrotizing; Flesh-eating bacteria; Soft tissue gangrene
Causes, incidence, and risk factors
Necrotizing subcutaneous infection or fasciitis can be caused by a variety of bacteria including oxygen-using bacteria ( aerobic ) or oxygen-avoiding bacteria ( anaerobic ). A very severe and usually fatal fasciitis is caused by a virulent specie of streptococcus that is often referred to as the "flesh-eating bacteria" by the press. This type of infection develops when bacteria enter the body, usually through a minor skin injury or abrasion. The bacteria begin to grow and release toxins that:
Directly kill tissue Interfere with the blood flow to the tissue Digest materials in the tissue which then allows the bacteria to spread rapidly Cause widespread systemic effects, such as shock Infection may begin as a small reddish painful spot or bump on the skin. This quickly changes to a painful bronzed or purplish patch that expands rapidly. The center may become black and dead ( necrotic ). The skin may break open. Visible expansion of the infection may occur in less than an hour. Systemic symptoms may include fever , sweating , chills, nausea, dizziness, profound weakness, and finally shock. Without treatment death can occur rapidly.
Signs and tests
The appearance of the skin and underlying tissues and presence of gangrenous changes (black or dead tissue) indicates a necrotizing soft tissue infection. Imaging tests, such as CT scans, are sometimes helpful. Often a patient needs to go the operating room emergently, where a surgeon can diagnose such an infection. A Gram stain and culture of drainage or tissue from the area may reveal the causative bacteria.
Treatment
Powerful broad-spectrum antibiotics must be administered immediately. They are given intravenously (in a vein) to attain high blood levels of the antibiotic in an attempt to control the infection. Surgery is required to open and drain infected areas and remove (debride) dead tissue. Skin grafts may be required after the infection is cleared. If the infection is in a limb and cannot be contained or controlled, amputation of the limb may be considered. Sometimes pooled immunoglobulins (antibodies) are given by vein to help fight the infection. If the organism is determined to be an oxygen-avoiding bacteria (anaerobe) the patient may be placed in a hyperbaric oxygen chamber, a device in which the patient is exposed to 100% oxygen at several atmospheres of pressure.
Expectations (prognosis)
Outcomes are variable. The type of infecting organism, rate of spread, susceptibility to antibiotics, and how early the condition was diagnosed all contribute to the final outcome. Scarring and deformity are minimal outcomes for this type of disease. Fatalities are high even with aggressive treatment and powerful antibiotics. Untreated, the infection invariably spreads and causes death.
Calling your health care provider
This disorder is severe and may be life-threatening, so consult your health care provider immediately. Call your health care provider if signs of infection occur around a skin injury: pain, swelling , redness, drainage of pus or blood, fever , or other similar symptoms.
Prevention
Clean any skin injury thoroughly. Watch for signs of infection such as redness, pain, drainage, swelling around the wound , and consult the health care provider promptly if these occur.