A DAN Member's Brush With the Rare Flesh-Eating Disease Ends Well
By Laurie Gowen, DAN Medical Information Specialist
What's necrotizing fasciitis?
The quick answer is that it's an insidious infection of the soft tissue that causes death of the infected area. It can ruin a perfectly good dive trip, or worse.
This 35-year-old male is healthy, with no significant medical problems to report. His certification status is unknown.
The diver was enjoying a lunch break between the second and third dives of the day on his liveaboard vacation. As he walked from the bow to gear up for another dive, he accidentally bumped his right lateral malleolus (outside anklebone) and caused a minor laceration over the bone. The injury did not appear to need treatment. Over the next day of diving, he had no problems with the ankle, so he continued to dive.
The following day, the diver noticed that his right anklebone was red and swollen; during his two dives the ankle seemed to be significantly more painful. After the second dive of the day, the injury and pain had worsened, so he took antibiotics that he had with him. As the next two days passed, even without any additional diving, his symptoms progressed from bad to worse.
He decided to seek medical attention on a nearby island, where the treating physician noted that the diver had a rapid pulse, inflammation around several pre-existing unrelated sores on his extremities, red streaking in his groin area and a fever of 104 degrees F (40 degrees C).
The original wound on the right malleolus appeared infected, and the surrounding tissue showed areas of necrosis (death). His right lower leg was swollen and tender, with a hemorrhagic area (or bleeding below the thin skin) behind the malleolus. The physician re-established antibiotic therapy and then contacted DAN for assistance in evacuating the diver to appropriate care.
In the evaluation at the hyperbaric facility on the mainland, the diver was diagnosed with cellulitis (tissue inflammation below the skin) of the right lower leg and right ankle pain. Within only two days of his noticing redness and swelling in the ankle, this diver may have had a condition known as necrotizing fasciitis (pronounced "FASH-ee-igh-tiss") and possible decompression sickness in the ankle.
What is this disease? Could he also have had DCS in his ankle? How effective is hyperbaric therapy for this type of injury?
Necrotizing fasciitis is an infection of subcutaneous tissue and the underlying fascia (pronounced "FASH-ee-uh," a sheet or band of fibrous connective tissue enveloping, separating, or binding together muscles, organs and other soft structures of the body). This infection, also know as "flesh-eating disease," is severe enough to cause necrosis of involved tissue. The original infection may begin, as in this diver's case, with a seemingly benign trauma site. Within 24 hours, it becomes red, swollen and tender, and it can quickly spread. Within the next 24 to 48 hours, symptoms can worsen, and eventually the area can show purple or black dead tissue.
Necrotizing fasciitis can be caused by many different types of bacteria. In most cases there are two or more species of bacteria, one of which is usually an "anaerobe," a bacterium that does not require oxygen to survive, and in fact is usually inhibited or killed by high levels of oxygen in the tissue.
At this point, sepsis typically occurs. Sepsis is the body's reaction to serious infection, which manifests itself as high fever, increased heart rate and increased respiration which, when left untreated, can lead to septic shock. Along with the signs and symptoms listed above, significant undermining of the skin and subcutaneous tissue usually reaches beyond the visible wound site. If the wound remains untreated, the necrosis can involve the muscle. Aggressive therapies such as surgery, intensive antibiotic therapy and oxygenation of the tissue are necessary for adequate treatment.
Surgical intervention, or debridement (removal of dead tissue), is a very aggressive but primary therapy in treating necrotizing fasciitis. The necrotic (dead) skin, subcutaneous tissue and fascia are removed to expose healthy underlying tissue. This debridement may need to be repeated as many as three to five times before the necrotizing process is halted.
In conjunction with debridement, antibiotics constitute an important part of wound management. Over time, recommendations on which antibiotic to prescribe have changed due to resistance to more frequently prescribed antibiotics and the availability of new drugs. Penicillin and clindamycin (an antibiotic used for treatment of skin infections) appear to be effective drugs, but other antibiotics may be required, depending on the sensitivity of the infecting bacteria. In this case, the fasciitis was due to staphylococcus and streptococcus bacteria, both commonly found on the surface of the skin and most of the objects we touch each day. The skin acts as a barrier to bacterial invasion and once it is broken, susceptibility to infection increases.
Along with surgery and antibiotics, clinical evidence suggests that hyperbaric oxygen offers additional benefit for necrotizing fasciitis. Hyperbaric oxygen increases the oxygen within the body's tissues and forces oxygen into hypoxic, or oxygen-deficient, tissue. While hyperbaric oxygen won't heal dead tissue, it will decrease edema, or fluid accumulation, and, in supplying oxygen to hypoxic areas, it kills anaerobes (bacteria that do not require oxygen) and promotes the growth of new blood vessels within soft tissue.
The course of necrotizing fasciitis will vary from person to person, depending on the following:
1) Elapsed time before treatment;
2) The individual's own immune system and any other systemic diseases, such as cancer and diabetes, the patient may have; and
3) Use of drugs that can depress the immune system, such as prednisone.
Unfortunately, necrotizing fasciitis has a fairly high mortality rate. Fortunately, for this particular diver, factors 2 and 3 were not a concern. However, the increase in pain after diving, while likely due to activity causing stress on the infected ankle, also raised the question of possible DCS.
Decompression sickness can present with pain-only symptoms. If the symptoms resolve after hyperbaric treatment, this supports the diagnosis of DCS. It is difficult to know which diagnosis, (DCS or infection) to attribute to this ankle pain. However, the pain was 90 percent better after the initial treatment. Could this decrease in symptoms during treatment indicate that the diver had DCS in the ankle? Alternatively, did the pain lessen because hyperbaric oxygen helped to treat his infection?
As with many dive injuries, there may be more than one condition to diagnose and treat. This diver was fortunate to receive a rapid evacuation and immediate therapies for both cellulitis and DCS.
On his first day at the hyperbaric facility, the diver received aggressive antibiotic treatment and a U.S. Navy Treatment Table 6. During the hyperbaric treatment, he showed significant improvement of the ankle pain. The increased pain that the diver experienced during the dives on the second day and the resolution of pain during the initial US Navy Treatment Table 6 may also indicate the presence of DCS.
For the necrotizing fasciitis, he then underwent surgical debridement, followed by multiple hyperbaric treatments. He continued receiving antibiotics. When doctors discharged him from the hospital, they prescribed six weeks of intravenous antibiotics. He was expected to make a full and complete recovery.
The ocean is a host to many bacteria that under the right circumstances can cause serious infection in humans. Small cuts or lacerations occurring in a marine environment can become easily infected if left unattended. Beware of the harmless little nicks!
The treating hyperbaric physician could not rule out DCS as a possible concurrent illness: the patient did appear to benefit from hyperbaric therapy. Due to the presence of a possible pre-existing infection, the diver's immune system may have been impaired even prior to diving.