Necrotizing fasciitis is a rare, severe soft tissue infection typically by Group A streptococci, marked by necrosis of subcutaneous tissues with involvement of the fascia.
The disease is related to the following processes: infectious and has an incidence of about 18 / 100.000.
Necrotizing fasciitis refers to the acute infection and necrosis of the fascia, the layer of connective tissue that surrounds most of the body tissues, like muscles, vessels and nerves. The infection is caused by certain bacteria that seem to “eat” the skin and subcutaneous structures of the body, resulting in a grotesque appearance, hence the name “flesh eating disease”.
Necrotizing fasciitis is common in cases of chronic infections (chronic liver disease, chronic renal disease) or in immunocompromised individuals, for example, in diabetics, HIV patients, those undergoing cancer chemotherapy or organ transplant patients. Bacteria enter the body through a break in the skin like cuts, abrasions, lacerations or surgical wounds.
The disease is caused by certain bacteria including the following  :
It may also be due to opportunistic fungal infections inclding:
Based on etiology, necrotizing fasciitis is classified into following categories:
The incidence of the disease is 1:10,000. It is more common in Asian and African countries. A male dominance with a 2-3:1 ratio has been recorded. The disease is rare in children.
The incidence is higher in immunocompromised patients, patients with neutropenia, individuals harboring open wounds, in the elderly, pregnant women and in obese people.
The toxins (most commonly those released by group A beta hemolytic Streptococci (GABS) and Streptococcal pyrogenic exotoxins (SPEs) A, B, and C) released by the aerobic bacteria breakdown the skin and subcutaneous tissues, invading the deeper structures . They cause the inhibition of immune response of the host and also cause tissue hypoxia, causing the gram negative bacteria to grow into the infected tissues . Vascular occlusion and ischemia follow. The infected tissue eventually begins to die (necrosis) . The bacteria enter the blood stream eventually, causing sepsis and shock.
The morbidity and mortality rates associated with necrotizing fasciitis are high. If prompt treatment is not given, limb amputation will be required. A mortality rate of 20% to 75% has been found. Permanent disfigurement is the commonest complication of majority of the cases. Average life span of these patients has been found to be 38 to 44 years.
During the first 2 days, the following clinical features are present:
Over the next 2 to 3 days, the clinical features include:
After another 2 days, the following grave complications are seen:
The following investigations are helpful in diagnosing necrotizing fasciitis.
Imaging techniques for the investigation of necrotizing fasciitis include the following.
The treatment of necrotizing fasciitis consists of the following.
The following preventive measures are effective in reducing the occurrence of necrotizing fasciitis.
Necrotizing fasciitis, commonly known as “flesh eating disease” is the disorder in which bacteria enter the body through open wounds. Individuals, in whom the immune defense mechanisms are low, are particularly susceptible to the disease. The bacteria “eat” the skin and the underlying tissues. The structures underneath are exposed.
If infection spreads to a large area and prompt medical care is not provided to the patient, amputation of the affected organ may be required. The patient may even die if not given adequate treatment. As bacteria enter through the breaks in the skin, it is vital to keep all sorts of wounds, cuts and abrasions clean. With proper care, the disease can be prevented.