YOUR PATIENT, Ted Hanson, 41, was bitten by a spider while working in his yard several days ago. Now he has a slight fever and complains of severe pain in the affected arm, but otherwise he doesn't appear to be seriously ill.
Appearances can be deceiving: If he's in the early stages of necrotizing fasciitis infection, his life is in danger. Popularly known as the flesh-eating infection, necrotizing fasciitis can progress rapidly, destroying all skin, muscle, and fat in its path within days or hours. Without fast, appropriate treatment, your patient may lose his arm or die.
Although uncommon in healthy people, necrotizing fasciitis is on the rise among chronically ill and immunocompromised patients, including those with human immunodeficiency virus (HIV), diabetes mellitus, or organ transplant. In children, it's a rare complication of varicella (chickenpox).
Mr. Hanson has a history of diabetes mellitus. Because an insect bite can open the door to infection in someone already compromised by chronic illness, you need to seriously consider the possibility that his unusual level of pain points to necrotizing fasciitis. Here, I'll explain how to recognize and treat this fast-moving infection before it's out of control.
Getting a break
Necrotizing fasciitis is a deep-seated, inflammatory infection of fascial tissue leading to necrosis of subcutaneous tissue and extensive undermining. It starts when a pathogen enters the body through a break in the skin. Although many pathogens can trigger the infection, the most common culprits are group A hemolytic streptococci, which are the most common cause of pharyngeal strep infections, and Staphylococcus aureus. Other aerobic or anaerobic pathogens that may cause necrotizing fasciitis include Bacteroides, Clostridium, Peptostreptococcus, Enterobacteriaceae, coliform, Proteus, Pseudomonas, and Klebsiella. Many cases of necrotizing fasciitis involve more than one pathogen.
Predisposing factors include surgical or traumatic wounds (including wounds involving foreign bodies), drug injection (especially injection of contaminated street drugs), burns, frostbite, insect bites, and other skin lesions (such as open sores or varicella). Sometimes the infection is idiopathic. Often a concurrent condition, such as diabetes, cancer, alcoholism, obesity, or malnutrition, allows the infection to take hold.
Like Ted Hanson, a patient with necrotizing fasciitis may appear deceptively well at first. Typical early signs and symptoms include a sudden onset of severe pain out of proportion to the injury, fever, flulike symptoms, and swelling at the injury site.
The hallmark of necrotizing fasciitis is quickly moving erythema at the wound, with the margins of infection spreading to normal skin without being raised or sharply demarcated. As the infection progresses, the skin becomes dusky or purplish near the site of insult and bullae containing purulent fluid appear. Beneath the surface, skin and subcutaneous tissue separate from deeper fascia.
Progressive anesthesia at the site indicates nerve damage. If the infection involves gas-forming organisms, such as Clostridium or some strains of Bacteroides or Escherichia coli, the infection site may contain subcutaneous gas.
Because the infection does its damage under the surface, it can be difficult to recognize at first, and subcutaneous necrosis and tissue separation may be far advanced by the time of diagnosis. Prepare the patient for aggressive treatment, including intravenous (I.V.) antibiotic therapy, surgical debridement, and possibly hyperbaric oxygen (HBO) therapy.
Responding to an emergency
Consider necrotizing fasciitis an emergency and intervene as follows, maintaining contact and standard precautions:
- Administer oxygen.
- Establish I.V. access, avoiding use of an infected extremity.
- Obtain specimens for blood work, urinalysis, and cultures. (Wound tissue specimens are usually collected during wound debridement.) Lab tests include complete blood cell count and differential; electrolyte, glucose, blood urea nitrogen, and creatinine levels; and arterial blood gas analysis.
- Start I.V. fluids and antibiotics as directed by an infectious disease specialist.
- Initiate cardiac monitoring.
- Insert an indwelling urinary catheter unless the infection involves the perineal area. (See Recognizing Fournier Gangrene.)
- Obtain surgical and infectious disease consults.
- If ordered, prepare the patient for imaging studies, such as X-rays, computed tomography, or magnetic resonance imaging, to check for gas and necrosis in subcutaneous fascial planes.
- Prepare the patient for emergency surgery to debride the wound.
HBO: A breath of fresh air
Combined with antibiotics and surgical debridement, HBO therapy can promote healing by encouraging growth of epithelial tissue and new blood vessels. By delivering highly concentrated oxygen under pressure, HBO increases the partial pressure of oxygen in the blood, reducing hypoxia and improving tissue oxygenation. Better oxygenation encourages vasoconstriction, which reduces edema, and high oxygen tensions help destroy anaerobic pathogens.
Most HBO sessions last between 1 and 2 hours. The duration of therapy varies, depending on facility protocol and the patient's condition and response. At first, he may undergo two or three sessions a day, with the number tapered as healing progresses. A patient with necrotizing fasciitis may need 20 or more HBO treatments.
Nursing care considerations
During your patient's treatment and recovery, support him with these interventions:
- Frequently assess him and lab results for signs and symptoms of life-threatening complications, such as gangrene, sepsis, coagulation disorders, and multiple organ dysfunction.
- Monitor the infection site for changes, such as expansion of edema, color changes, and an increase or decrease in pain.
- Modify antibiotic therapy as directed according to culture and sensitivity results.
- Use a standard pain-rating scale to document his pain. Provide opioid pain medication as indicated, especially before dressing changes, which can be excruciating. Consider patient-controlled analgesia if appropriate for your patient.
- Obtain a nutritional consult to make sure he gets enough calories and nutrients to support wound healing. Initiate enteral feeding if indicated.
- Provide ongoing emotional support to the patient and his family. Besides confronting the possibility of death, he faces the threat of amputation or disfigurement and is likely to need more surgery and extensive skin grafting in the future. Assess for anxiety and depression, provide information about rehabilitation, and encourage him and his family to seek additional counseling to deal with long-term role changes and body image issues.
Mr. Hanson's infection, which began with a brown recluse spider bite, is recognized in time. Thanks to antibiotics, surgical debridement, and a course of HBO therapy, the infection is brought under control, saving his arm and his life. Even so, he remains hospitalized for several weeks and will need reconstructive surgery and skin grafting.
By recognizing necrotizing fasciitis early and initiating aggressive treatment, you stopped this voracious infection in its tracks.
Barbara Wyand Walker is an infection control/employee health nurse at Greenbrier Valley Medical Center in Ronceverte, W.Va.
SELECTED WEB SITES
Centers for Disease Control and Prevention http://www.cdc.gov/ncidod/dbmd/diseaseinfo/groupastreptococcal_g.htm
Medical-Surgical Nursing Journal Online CE: http://www.ajj.com/services/pblshng/msnj/ceonline/11033036/default.htm
Undersea and Hyperbaric Medical Society http://uhms.org
Last accessed on September 1, 2004.
Recognizing Fournier gangrene
When necrotizing fasciitis affects the scrotum and perineal area, it's called Fournier gangrene. It begins with pain and itching of the scrotal skin in men and labia in women, progressing to swelling of tissue to twice normal size, necrosis, and gangrene. In 2 to 7 days, the skin becomes necrotic, and a characteristic black spot appears.
In men, this infection may resemble other problems, such as orchitis, epididymitis, torsion, or even a strangulated hernia. In women, it may develop after a vaginal hysterectomy or cesarean section. Arrange for a urologic consult for any patient with Fournier gangrene.
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