What is Necrotizing Faciitis?

Necrotising Fasciitis is a rare disease in which the connective tissue of the fascia between the muscles or around organs becomes inflamed and eventually necrotic due to a sudden, widespread microbial infection.  There are two types of Necrotizing Fasciitis: type I is poly-microbial and type II is mono-microbial. Type I, poly-microbial is the more common cause of Necrotizing Fasciitis.

Why does Necrotizing Fasciitis occur? No one knows the exact causes of Necrotizing Fasciitis, however, it is well known that people who are: immune-compromised, have diabetes, chronic systemic diseases are more predisposed to the condition. Necrotizing Fasciitis has, on even rarer occasions, effected otherwise previously well and healthy persons.

One of the hypothesis about the cause of Necrotizing Fasciitis is that a person who is malnourished, in a weakened state, or immune-compromised, will cause opportunistic bacteria to try to multiple more commonly.

Signs and Symptoms of Necrotizing Fasciitis

Because the infection often occurs deep into the body tissue very limited signs are observed on the skin or surround area of the limb until the disease has thoroughly progressed. Often, by the time Necrotizing Fasciitis is diagnoses, urgent surgery and widespread intravenous antibiotics are the only solutions.

If the infection is superficial (less common presentation), then the localized areas will show signs associated with infection, such as inflammation, swelling, redness, urticaria, itchiness, pyrexia, and pain.

If the infection is deep in the body tissues, then little will be seen or felt, until the infection progresses. Then the following signs may be identified: fevers, nausea, vomiting, diarrhoea, headache, and deep muscular pain that seems excessive given the outward appearance of the limb. 

Pathophysiology of Necrotizing Faciitis

Necrotizing Fasciitis is often referred to as ‘Flesh Eating Virus’ or ‘Flesh Eating Bacteria.’The term ‘Flesh Eating Virus’ and ‘Flesh Eating Bacteria’ is an incorrect view of necrotizing fasciitis. First of all, necrotizing fasciitis refers to a syndrome caused by bacteria, not a virus and in reality, the bacterium does not actually ‘eat’ the cells. Instead, what occurs, is the poly-microbial or mono-microbial infection causes a breakdown of the cell walls within the tissues of the skin, muscles, and fascia which results in the release of streptococcal pyogenic exotoxins – which, in turn, cause the non-discriminatory activation of T-cells and subsequent widespread overproduction of cytokines . Excess cytokines cause a further release of cell mediators, breakdown of the cell structure, and clotting factors, resulting in haemorrhagic shock, such as DIC.