Necrotizing Fasciitis - Symptoms and Treatment

Necrotizing fasciitis may be monomicrobial and caused by S. pyogenes , Vibrio vulnificus , or Aeromonas hydrophila. It is also known as flash eating disease and may occur following surgery or in patients with peripheral vascular disease, diabetes mellitus, decubitus ulcers, and spontaneous mucosal tears of the gastrointestinal or gastrourinary tract (i.e., Fournier gangrene). This type of infection develops when bacteria enter the body, usually through a minor skin injury or abrasion.

Necrotizing Skin Infections are estimated that there are between 90 and 200 cases per year in Canada, and about 20 to 30 percent of these are fatal. Symptoms include redness (erythema), swelling ( edema ) and tenderness. The degree of pain typically is greater than the severity of these findings and the person appears terribly ill. The original skin wound is often evident. Skin changes may include bullous lesions (blisters) and local skin anesthesia (due to blocking of little vessels in the skin). A crinkly or crackling feeling called crepitus indicates gas in the tissues but occurs in only about half of cases.

Other necrotizing skin infections spread on the outer layers of skin and are termed necrotizing cellulitis. Several different bacteria, such as Streptococcus and Clostridia , may cause necrotizing skin infections, although in many people the infection is caused by a combination of bacteria. The streptococcal infection in particular has been termed "flesh-eating disease" by the lay press, although it differs little from the others. Some necrotizing skin infections begin at puncture wounds or lacerations, particularly wounds contaminated with dirt and debris.

Necrotizing fasciitis is a serious condition in which muscle and fat tissue are broken down as a consequence of infection. Necrotizing fasciitis is a complication of severe group A streptococcal infection (GAS)(Streptococci pyogenes). Other symptoms may include fever, chills, and nausea and vomiting or diarrhea. The skin commonly becomes red, swollen, and hot to the touch.

Infection is deep in the tissue, these signs of inflammation may not develop right away. Necrotizing fasciitis is a progressive, rapidly spreading, inflammatory infection located in the deep fascia, with secondary necrosis of the subcutaneous tissues. Because of the presence of gas-forming organisms, subcutaneous air is classically described in necrotizing fasciitis.

Causes of Necrotizing Fasciitis

This disease is caused by one or more aggressively multiplying bacterial species, most often group A strep. Many people may carry these bacteria in the nose, throat, or on their skin, without getting sick, but these bacteria can also cause sore or strep throat, scarlet fever, skin infections, and rheumatic fever. Researchers do not fully understand why Group A streptococcus bacteria, on rare occasions, cause necrotizing fasciitis. It is known that these bacteria make poisons that destroy body tissue directly, as well as causing the body's immune system to destroy its own tissue while fighting the bacteria.

• Injury.
• Chickenpox.
• Diabetes mellitus.
• Weakened immune system.
• Bacterial invasion.

Signs and Symptoms of Necrotizing Fasciitis

Sign and symptoms may include the following :

• Nausea.
• Vomiting.
• Fever.
• Swollen skin .
• Patchy skin color.
• Diarrhea.
• Chills.

Treatment for Necrotizing Fasciitis

Treatment of necrotizing fasciitis is most effective if the infection is recognized in time. The antibiotics are generally administered intravenously (in a vein) in order to attain a sufficiently high blood level of the antibiotic to control the infection. Medications to raise blood pressure, blood, and anti-globulins may need to be administered at the same time. If the infecting organism is an oxygen-avoiding bacteria (anaerobe), a hyperbaric oxygen chamber may be used to expose the bacteria to 100% oxygen at several atmospheres of pressure. Surgery is performed to open and drain infected areas and to 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, the amputation of the limb may be necessary.

Treatment may include:

• Use of vancomycin to treat methicillin-resistant S aureus is often discussed and may depend on the clinical situation.
• Antibiotics( Penicillin G, Clindamycin, Metronidazole)as soon as possible.
• Combination therapy: This approach involves the use of 2 or 3 antibiotics. To cover aerobes (usually gram-negative organisms), ampicillin and gentamicin are useful.
• Initial treatment often includes a combination of intravenous antibiotics including penicillin , vancomycin and clindamycin.