Postprocedural Necrotizing Fasciitis: A 10-Year Retrospective Review

By Miller, Aaron T Saadai, Payam; Greenstein, Alexander; Divino, Celia M

Necrotizing fasciitis (NF) is a severe soft tissue infection, which has a reported 25 per cent to 60 per cent mortality rate. In addition, NF has been reported to occur after invasive procedures. We present a 10-year retrospective study on postprocedural NF and its differences with community-acquired NF. A retrospective study was conducted from 1996 to 2006. Charts were searched using International Classification of Diseases, 9th Revision codes for NF and gas gangrene. Patients who developed NF in the area of their previous procedure without any other inciting cause of the NF were deemed eligible for the study. Eleven patients met eligibility criteria. Seven patients’ initial procedures were elective, whereas four were semiemergent. The median age was 48 years (range, 24-81 years). The time between the initial procedure and operation for NF varied from 3 days to over 3 months. No single laboratory value helped in diagnosing NF. Sixteen different bacteria were isolated from the 11 patients. Ten of 11 patients required multiple debridements. There were four mortalities, three of whom had comorbidities known to predispose to infection. NF is a rare but serious complication after invasive procedures. As a result of important differences that exist between postprocedural and community-acquired NF, we propose that postprocedural NF should be classified in its own subcategory. NECROTIZING FASCIITIS (NF) is a severe, highly fatal infection of the subcutaneous tissue, which causes local necrosis and can lead to systemic sepsis.1 The first reference to NF was in 1764, when a progressive soft tissue necrotizing gangrene of the male genitalia was described by Baurienne. In 1883, Fournier described infectious gangrene of the scrotum and penis, which is known today as Fournier’s gangrene. Although Meleney described the entire clinical spectrum of NF in 1924, the term NF was not coined until 1952, when it appeared in an article by Wilson.2

Despite advances in the management of this entity, mortality remains high with rates ranging from 25 per cent to 60 per cent as reported in the literature.3 Most cases of NF occur in the presence of an identifiable cause such an epidermal break allowing bacterial entry into the tissues or as an occult infection after an event such as a perforated viscus.3 When the diagnosis of NF is made, aggressive treatment should ensue, the most important components of which are adequate resuscitation with intravenous fluids and the initiation of broad-spectrum antibiotics. After the patient is stabilized, aggressive surgical debridement of all devitalized tissue should follow.4 Most of the literature on the subject of NF has described its occurrence and management in a community-acquired setting.5,6 The purpose of this study is to examine the development of NF in a hospital setting after operative or other invasive procedures and to explore the differences between community- acquired and postprocedural NF.

Materials and Methods

Hospital charts from The Mount Sinai Hospital between 1996 and 2006 were searched using the International Classification of Diseases, 9th Revision codes 728.86 (NF) and 040.0 (gas gangrene). We reviewed the charts of all patients identified by the search and included those patients who had a preceding operation or invasive procedure within 6 months before the development of NF. Patients diagnosed with Fournier’s gangrene were excluded. We then obtained information on the type of procedure performed before the development of NF, the underlying medical conditions, presenting symptoms, laboratory values, bacteriology results, and hospital course.

The Mount Sinai Hospital is the teaching hospital for The Mount Sinai School of Medicine. Management decisions for each individual patient, in the study, were made either by the general surgery team or the patient’s primary team with consultation with the general surgery team. Housestaff members of the general surgery team varied throughout the duration of this study and no individual attending surgeon was involved in more than two cases. This study was approved by The Mount Sinai Hospital’s Institutional Review Board.

Results

From 1996 to 2006, 11 cases met the criteria for inclusion in the study (see Table 1). The median age of the patients was 48 years (range, 24-81 years) with a female:male ratio of 4.5:1. Seven of the initial procedures involved the abdomen, two the groin (nonFournier’s), and two the extremities. Seven of those cases were nonemergent (four abdominal, two groin, and one extremity) and four were emergent (three abdominal and one extremity). The timeframe between the initial procedure and operating for the NF ranged from 3 days to over 3 months.

Most patients presented with symptoms of pain and signs of a wound infection (i.e., erythema and discharge). Seven people had a white blood cell count greater than 12.5 x 10^sup 9^/L, four had serum sodium levels less than 135 mmol/L, and six had a blood urea nitrogen greater than 15 mg/dL. Of the six patients who had imaging studies (all CT scans), five had presence of abnormal areas. Multiple organisms were grown in the wound cultures of eight patients with a total of 16 different organisms isolated (Table 2). Escherichia coli was the most common organism isolated followed by Klebsiella pneumoniae. Four of the 11 patients died. Each patient had at least one operative debridement for the NF and 10 of 11 had more than one. The mortality rate was 36 per cent (four of 11). Three of the four patients who died had comorbid conditions (morbid obesity or chemotherapy) that put them at increased risk for infection.

Discussion

Although quite rare, NF is a serious and highly lethal entity. The majority of reported cases of NF occur in a community-acquired setting,5,6 but NF can result from nosocomial infection. In this study, we showed that NF can be a devastating complication for patients who have undergone recent surgery or invasive procedures. In addition, we reveal trends among these patients and make recommendations regarding their management.

Despite newer surgical techniques and broadspectrum antibiotics, mortality in this subset of patients (36%) is consistent with the reported literature.3 Two patients who died were morbidly obese. Patients with morbid obesity have alterations in frequencies and expressions of T-cells as well as an increased risk for postoperative wound infections; thus, morbid obesity appears to put patients at increased risk for the development of postoperative NF.7,8 Another patient who died was receiving chemotherapy just before her death. Chemotherapy often leads to neutropenia and predisposes people to an increased risk of an infection,9 which can then be difficult to eradicate.

The type of initial procedure seems to be an important factor for patients who develop NF. Seven of the cases can be classified as at least clean-contaminated secondary to manipulation of the gastrointestinal tract. Two cases involved groin incisions, which are more prone to infection.10,11 Two more cases followed laparoscopic bowel procedures, which has been reported previously in the literature and may be an important risk factor worth further study.12 Whether the procedure is done electively or emergently does not seem to affect the incidence of NF.

The time period between the initial procedure and the development of NF is quite variable. The range was 3 days to 3 months, which indicates that patients with previous invasive procedures are prone to NF beyond the immediate postoperative period. Thus, a high degree of clinical suspicion must remain for those who present with signs and symptoms of sepsis or wound infection months after the initial procedure. Perioperative antibiotic regimens, when used, varied widely, and there did not appear to be any relationship between antibiotic selection and disease course.

Based on the results of our study, we believe NF should be classified into three separate categories. The first, Fournier’s gangrene, is a specific form of NF involving the scrotum, penis, or perineum.13 Its epidemiology, treatment, and outcome has been well described in the literature.14,15

The second and third categories are communityacquired NF and postprocedural NF, respectively. An important difference between the two groups is the organisms associated with each. Most series in the literature of community-acquired NF involve primarily group A streptococci16-18 with or without associated Staphylococcus aureus or Staphylococcus epidermis infection (described as type II NF). Type I NF has also been reported, which involves anaerobic bacteria with streptococci other than group A.14 In our series, we report eight of 11 patients with polymicrobial infections for a total of 16 different organisms. The diversity of organisms is probably the result of manipulation of areas that are contaminated (i.e., gastrointestinal tract), which leads to bacterial translocation or frank spillage of contaminated contents. This can make it more difficult to treat NF infections and might require broader and longer coverage with antibiotics for full eradication.

A second difference between the groups is in the diagnosis of NF. Wall et al. determined certain laboratory criteria that could help diagnose NF in equivocal circumstances. The criteria were white blood cell count greater than 14 x 10^sup 9^/L, a serum sodium less than 135 mmol/L, and a blood urea nitrogen greater than 15 mg/ dL.19 However, we did not find that there was a strong correlation between these or any other laboratory values associated with NF. We feel the diagnosis of NF is better made based on clinical examination. Many of our patients had erythematous, nonhealing wounds and pain out of proportion to what would be expected postoperatively. Other signs and symptoms reported in the literature such as high fevers, mental status changes, and subcutaneous emphysema were highly variable among our patients. A possible explanation for this result is patients who have had a previous procedure are highly focused on that particular area when something is abnormal; thus, they seek treatment while the infection is still localized and before the development of systemic symptoms. TABLE 1. Preoperative Characteristics and Data of All Patients

TABLE 2. Operative and Postoperative Data on All Patients

When the diagnosis of NF is in doubt and the patient is stable, imaging studies may be helpful in clarifying the diagnosis. Our modality of choice is a CT scan of the affected area because it is quick and easily accessible. Five of our patients who underwent a CT scan had evidence of abnormal areas of gas, which aided in the diagnosis. There have been some reports in the literature that MRI may be superior to CT scan because of better imaging of the soft tissues and lack of contrast needed, but as a result of the length of time needed for the test and its general inaccessibility, we would not recommend it as a first-line test in these situations.20,21

Once the diagnosis of NF is made, the patient should be placed on broad-spectrum antibiotics until specific organisms are identified through culture. After antibiotics are instituted, standard management for NF is surgical debridement. However, surgical debridement requires a different approach in patients with community- acquired versus postprocedural NF, a third difference between the two groups. For the latter group, surgeons should be aware that the presence of postprocedural inflammation and scarring can render the initial debridement difficult to complete and lead to the requirement of multiple debridements.

Conclusion

Although postprocedural NF is an uncommon occurrence, it can have fatal consequences. The cases in this review suggest that the diagnosis, bacteriology, and surgical treatment of postprocedural NF are different from standard community-acquired NF. Physicians should be aware of these differences to improve patient care and potentially decrease morbidity and mortality.

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AARON T. MILLER, M.D., PAYAM SAADAI, M.D., ALEXANDER GREENSTEIN, M.D., CELIA M. DIVINO, M.D.

From the Division of General Surgery, The Mount Sinai Hospital, New York, New York

Address correspondence and reprint requests to Celia M. Divino, M.D., 5 East 98th Street, Box 1259, Department of Surgery, Mount Sinai Medical Center, New York, NY 10029. E-mail: celia.divino@mountsinai.org.

Copyright Southeastern Surgical Congress May 2008

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