Treating 'flesh eating' bacteria requires speedy and decisive action

Necrotizing fasciitis can be a killer

Most wounds are debilitating, painful, and costly. Wounds associated with necrotizing fasciitis, however, can be downright deadly. The popular media have had a field day with the so-called "flesh-eating bacteria," and have characterized it as the latest scourge that health-conscious Americans need to fret about. But this time, the hyperbole has some substance behind it.

Necrotizing fasciitis is a limb- and life-threatening soft-tissue infection that occurs as a complication of group A streptococcal infection, though only a few of the 80+ strains of streptococcus produce the disease. Group A strep infection often presents as a benign low-grade cellulitis that can quickly deteriorate into necrotizing fasciitis.1

Experts say necrotizing fasciitis must be treated aggressively with large doses of antibiotics soon after the disease process has begun, followed quickly by surgical debridement and aggressive wound care once the patient is stabilized. Without proper medical measures, the disease can kill within a matter of days. Mortality rates approaching 40% have been reported, and death can occur in 24 to 48 hours after the onset of symptoms. Besides the danger to victims, the bacteria can pose a threat to health care workers, as well. (See case study, p. 39.)

Clinical presentations also can include high fever, anxiety, and agitated mental status. Discolorations of the skin can range from scarlet to deep purple, with extensive swelling and sometimes severe pain. The onset and progression of symptoms often occur quickly, from within a day to several days. In some cases it only takes a matter of hours from the time of first symptom presentation for sheets of skin to begin peeling off the patient's body. If discovered early, the spread of necrotizing fasciitis can be checked.

Symptoms can advance to suppuration, the formation of extensive abscesses, and the destruction of large portions of cellular and adipose tissues. Intense morbid action can lead to mortification of the skin and underlying tissue, implied by blood- or dark serum-filled blebs and a dark coloration of the skin. Extensive gangrene is considered a serious complication and can cause death from septicemia. If the streptococci invade the lymphatics and connective tissue spaces, they may block antibiotic access.2

Necrotizing fasciitis related to small vessel disease

According to the Undersea & Hyperbaric Medicine Society (UHMS) in Kensington, MD, clinical manifestations include extensive dissection and necrosis of the superficial and deep fascia. The infection leads to the undermining of adjacent tissue and marked systemic toxicity. Necrosis of the overlying skin occurs secondary to thrombosis of the subcutaneous blood vessels. Initial local pain is replaced by numbness or analgesia as the infection involves the cutaneous nerves. Most cases of necrotizing fasciitis occur after minor trauma or surgery; the highest incidence is seen in patients with small vessel disease such as diabetes mellitus.3

The first priority always is to stabilize the patient and minimize the risk of additional infections. Then care turns to the often enormous open wounds caused by the disease process. If tissue loss is great and has resulted in disfigurement, major surgical reconstruction, such as flaps or skin grafts, often are indicated. As the wounds heal, or if they were limited in size because treatment was given before necrosis got out of hand, more conventional wound care options are in order.

"My preference is to irrigate these wounds with normal saline only, using a 30cc syringe and a 19-gauge needle, and to use a good deal of force," says Elaine Mrowczynski, BSN, CETN, an enterostomal therapy nurse at Shore Memorial Hospital in Somers Point, NJ. "If there is any debris or bacteria left in the wound, that should get it out."

Her next step is to apply a water-based aloe gel (Mrowczynski prefers Carrasyn Gel, Carrington Laboratories, Irving, TX), and a packing of saline-soaked gauze. "The gel provides a moist wound environment and is easy to use. We've found it to be very effective," Mrowczynski tells Wound Care. "We pack it in lightly, making sure that any undermined edges are in contact with the packing."

Care must be taken to avoid maceration of the surrounding skin when using the moist gauze dressing. Mrowczynski uses a barrier cream to protect the skin peripheral to the wound, making sure not to place the cream in the wound itself. She usually places a transparent covering over the wound and packing. Healing times vary greatly depending on wound size and a patient's overall condition.

Crushing injury leads to thrombosis, seroma cavities

Mrowczynski reports seeing about two to three cases of necrotizing fasciitis each year - a high number for a small community hospital such as Shore Memorial.

One case involved a 48-year-old man who presented after a crushing injury to his left leg. There were no bone fractures or skin lacerations. The patient was placed on a low air-loss bed.1

Within three days he developed deep-vein thrombosis and two large seroma cavities in the left thigh (one anterior and one posterolateral). Aspiration revealed serous fluid, the volume of which increased over the next few days. Open drainage and debridement with packing was performed on the wounds.

Daily nursing care included wound irrigation with normal saline using a 30cc syringe and a 19-gauge needle. Wounds were packed with a water-based aloe gel and soaked lap sponges (two for each wound), then covered with a dry sterile dressing secured with a bandage.

Two weeks after initial surgery, the patient's anterior wound was covered with a split-thickness skin graft. An unsuccessful attempt was made to close the lateral cavity with retention sutures. At discharge one week later, the dimensions of all wounds had shrunk considerably. Home wound care continued with the assistance of a visiting nurse. At a follow-up exam a month later, the anterior wound had healed completely and the posterior wound had healed by 95%.

Hyperbaric oxygen also has been reported as a beneficial treatment for patients with necrotizing fasciitis, according to the UHMS. In one study involving 29 patients treated over an eight-year period, mortality among those treated with surgical debridement and antibiotics was 66%, compared with 23% among those for whom hyperbaric oxygen treatment was added to the regimen.4 The authors noted that the hyperbaric group was more severely ill. Based on these results, the authors recommended the routine use of adjunctive hyperbaric oxygen in treating necrotizing fasciitis.

References

1. Ardire L, Mrowczynski E. Necrotizing fasciitis: Case study of a nursing dilemma. Ostomy Wound Mgmt 1997; 43:30-44.

2. Brantigan CO, Senkowsky J. Group A beta hemolytic streptococcal necrotizing fasciitis. Ostomy Wound Mgmt 1997; 43:32-39.

3. Undersea & Hyperbaric Medicine Society. Necrotizing soft tissue infections (subcutaneous tissue, muscle, fascia). 1996 Committee Report. Kensington, MD.

4. Eltorai IM, Hart GB, Strauss MB, et al. The role of hyperbaric oxygen in management of Fournier's gangrene. Int Surg 1986; 71:53.