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Necrotising fasciitis

What is necrotising fasciitis?

Necrotising fasciitis is a very serious bacterial infection of the soft tissue and fascia (a sheath of tissue covering the muscle). The bacteria multiply and release toxins and enzymes that result in thrombosis (clotting) in the blood vessels. The result is destruction of the soft tissues and fascia.

There are three main types of necrotising fasciitis:

Bacteria causing type 1 necrotising fasciitis include Staphylococcus aureus, Haemophilus, Vibrio and several other aerobic and anaerobic strains. It usually follows significant injury or surgery.

Type II necrotising fasciitis has been sensationalised in the media and is commonly referred to as flesh-eating disease.

Type III is caused by Clostridia perfringens or less commonly Clostridia septicum. It usually follows significant injury or surgery and results in gas under the skin: this makes a crackling sound called crepitus.

How do you get necrotising fasciitis?

Necrotising fasciitis may occur in anyone, in fact, almost half of all known cases of streptococcal necrotising fasciitis have occurred in young and previously healthy individuals. The disease may occur if the right set of conditions is present, these include:

Those at increased risk of necrotising fasciitis include diabetics, immunosuppressed individuals, obese people, drug abusers, and people with severe chronic illness.

What are the signs and symptoms of necrotising fasciitis?

Signs and symptoms vary between individuals but often some or all of the following are present.

Within 3-4 days of the initial symptoms the following may occur:

By about days 4-5, the patient is very ill with dangerously low blood pressure and high temperature. The infection has spread into the bloodstream and the body goes into toxic shock. The patient may have altered levels of consciousness or become totally unconscious.

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Necrotising fasciitis

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What treatment is available?

Once the diagnosis of necrotising fasciitis is confirmed, treatment should be initiated without delay. Patients must be hospitalised, the causative organism(s) identified and treated with high dose intravenous antibiotics, often in an intensive care unit.

It is absolutely vital than an experienced surgeon urgently removes all dead tissue.

Treatment to raise blood pressure, hyperbaric oxygen, and intravenous immunoglobulin may also be necessary.

What is the likely outcome?

If diagnosed and treated early, most patients will survive with minimal scarring. However if there is significant tissue loss, later skin grafting will be necessary and in some patients amputation of limbs is required to prevent death. Up to 25% of patients will die from the disease and complications such as renal failure and septicaemia (blood poisoning) increase the likelihood of death.

Prompt diagnosis and treatment is essential to reducing the risk of death and disfigurement from necrotising fasciitis.

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Author: Vanessa Ngan, staff writer

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