HEALTHNET

Necrotizing Fasciitis

From time to time, you hear about some sensational cases of flesh eating bacteria. How does it happen and how do we prevent ourselves from becoming the next victim?

(Posted on 29 September 2005)

Necrotizing fasciitis is a rare bacterial infection that is sometimes said to be infected with "flesh-eating" bacteria. During the period of May to August 2005, four cases of necrotizing fasciitis caused by Vibrio vulnificus were reported by the Centre for Health Protection (CHP) of the Department of Health.

Necrotizing fasciitis is a condition where bacteria attack the soft tissue and the sheath of tissue covering the muscle (fascia) by releasing toxins and enzymes that result in thrombosis (clotting) in the blood vessels. There are three main types of necrotizing fasciitis:

Type I (more than one bacteria involved): Staphylcoccus Aureus; Haemophilus, Vibrio and several other aerobic and anaerobic strains. The recent cases that occurred in Hong Kong were associated with Vibrio vulnifucus*.
Type II: due to Haemolytic group A streptococcus, the most famous flesh eating bacteria through the media in the past.
Type III: gas gangrene due to Clostridia perfringens or less commonly Clostridia septicum resulting in gas under the skin.

* Vibrio vulnificus normally lives in warm seawater. Environmental factors, such as warm water and moderate salinity, can increase the number of V. vulnificus organisms in shellfish.

How do you get the disease?

Almost half of all known cases of streptococcal necrotizing fasciitis occurred in young and previously healthy individuals. The disease may occur if the right set of conditions is present, these include:

An opening in the skin that allows bacteria to enter the body. This may be a small cut, graze or pinprick or a large wound due to trauma or surgery.
Direct contact with a person who is carrying the bacteria or the bacteria is already present elsewhere on the person.
Particularly invasive strains of streptococci or other bacteria.
Eating raw or undercooked shellfish, particularly oysters harvested from warmer waters.

Who is at risk?

Higher risk groups include:

Individuals with recent cuts, scratches, injuries.
Individuals with recent surgical procedures.
Individual with peripheral vascular diseases.
Alcohol/drug abusers.
Individuals taking aspirin or non-steroidal anti-inflammatory drugs.
Children with chicken pox (type II necrotising fasciitis).
Immunosuppressed individuals (diabetics, TB and chronic illness sufferers).
Elderly persons.
Women giving birth.

What are the symptoms?

Early symptoms (within 24 hours):

Usually a minor trauma or other skin opening has occurred (the wound does not necessarily appear infected).
Pain in the general area of the injury and worsening over time.
Flu like symptoms begin to occur, such as diarrhea, nausea, fever, confusion, dizziness, weakness, and general malaise.
Intense thirst occurs as the body becomes dehydrated.

Advanced symptoms (within 3-4 days):

Affected area starts to swell and may show a purplish rash.
The limb may begin to have large dark marks form that turn into blisters filled with blackish fluid.
Wound starts to die and the area becomes necrotic with a bluish, white, or dark, mottled, flaky appearance.
Severe pain.

Critical symptoms (days 4-5):

Blood pressure drops severely.
Temperature rises.
The infection has spread into the bloodstream and the body goes into toxic shock from the toxins that the bacteria are giving off.
The patient may have altered levels of consciousness or become totally unconscious.

Note that the early symptoms mimic so many other minor afflictions. Increased awareness and understanding of such conditions are important to encourage the public to seek for early medical attention.

What treatments are available?

Patients must be hospitalized, the causative organism(s) identified and treated with a high dose of intravenous antibiotics, ofteninanintensive care unit.
Experienced surgeon urgently removes all dead tissue. Amputation is sometimes needed to remove the affected limb.
Treatment to raise blood pressure, hyperbaric oxygen (meaning: high pressure oxygen, oxygen at a pressure greater than 1 atmosphere), and intravenous immunoglobulin may also be necessary.
Up to 25% of patients will die from the disease and complications such as renal (kidney) failure and septicaemia (blood poisoning)increasethe likelihood of death.

What are the preventative measures?

The single biggest preventative measure is keeping the skin intact.
Avoid exposure of open wounds or broken skin to seawater or salty water.
Wounds should be thoroughly cleansed with antibiotic/antiseptic ointments and properly covered.
Wear protective clothing (e.g., gloves) when handling raw shellfish.
Handle and keep raw seafood separately from cooked seafood, in order to prevent any chance of cross-infection.
For cooking shellfish in the shell, either boil until the shells open and continue boiling for 5 more minutes, or steam until the shells open and then continue cooking for 9 more minutes. Do not eat shellfish that do not open during cooking.

Source: Quality HealthCare