Necrotizing Fasciitis & Gas Forming Myonecrosis: 36 Patient Study (2012) PDF

Scandinavian Journal of Surgery 101: 51–55, 2012 Characteristics and differences in necrotizing fasciitis and gas forming myonecrosis: a series of 36 patients D. J. Tilkorn1, M. Citak2, T. Fehmer2, A. Ring1, J. Hauser1, S. Al Benna1, L. Steinstraesser1, B. Roetman2, H.-U. Steinau1 1 Department o...

Scandinavian Journal of Surgery 101: 51–55, 2012 Characteristics and differences in necrotizing fasciitis and gas forming myonecrosis: a series of 36 patients D. J. Tilkorn1, M. Citak2, T. Fehmer2, A. Ring1, J. Hauser1, S. Al Benna1, L. Steinstraesser1, B. Roetman2, H.-U. Steinau1 1 Department of Plastic Surgery, BG-University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany 2 Department of General and Trauma Surgery, BG University Hospital Bergmannsheil, Ruhr University Bochum, Bochum, Germany Abstract Background and Aims: Necrotizing fasciitis (NF) and gas forming myonecrosis (GFM), both being subtypes of necrotizing soft tissue infection (NSTI), are life threatening con- ditions sharing certain similarities. Despite the necessity of early and radical surgical debridement in necrotizing infections, the distinction between these entities is of clini- cal relevance since gas forming myonecrosis in a number of cases results from an under- lying abdominal cause and the focus of infection can be missed. This study was to evaluate the incidence and risk factors as well as the mortality rate in patients with NSTI and GFM. Material and Methods: All patients with NSTI treated in the authors’ hospital between January 2005 and December 2009 were enrolled in the study. Medical records, histologi- cal slides, microbiological and laboratory parameters as well as Computerized Tomog- raphy (CT) and magnetic resonance imaging (MRI) scans were reviewed for all patients. Differences between NF and GFM regarding hospital stay, number of surgical interven- tions and pre-existing comorbidities as well as mortality rate were analyzed. The labora- tory risk factor for necrotizing fasciitis (LRINEC) score was calculated in all patients on admission. Results and Conclusions: Thirty patients (17 female, 13 male) with necrotizing fasciitis with a mean age of 55 years (SD 15.5) were included in the study. There was no statisti- cally significant difference between survivors and deceased patients comparing the LRINEC score (n.s.). Patients with necrotizing fasciitis secondarily involving the trunk had a significantly higher mortality rate (OR 11.2; 95% CI = 1.7–72.3). In the majority of cases (12 cases), minor skin lesions were identified as the site of origin. Amongst all necrotizing soft tissue infections six patients (female n = 3; male n = 3) with a mean age of 61.5 years (SD 12.2) with non-clostridial gas forming myonecrosis were identified. Correspondence: Daniel-Johannes Tilkorn, M.D. Department of Plastic Surgery BG University Hospital Bergmannsheil Ruhr University Bochum Buerkle-de-la-Camp-Platz 1 G - 44789 Bochum Germany Email: [email protected] 52 D. J. Tilkorn, M. Citak, T. Fehmer, A. Ring, J. Hauser, S. Al Benna, L. Steinstraesser, B. Roetman, H.-U. Steinau Three patients had a history of malignancy and in three patients the infection was sec- ondary to major surgery. The mean LRINEC score was 8.5 (SD 1). Three patients (50%) died due to GFM. Early diagnosis and appropriate intervention is critical to provide accurate treatment decisions. Eradicating the differing primary sources of infection in GFM and NF will have a positive impact on outcome. Key words: Necrotizing soft tissue infection; gas forming myonecrosis; soft tissue infections; gas gangrene; mortality; LRINEC-score; necrotizing fasciitis Introduction mal trauma or minor skin lesions (2) most of the time represent the origin of infection. Necrotizing fasciitis (NF) and gas forming myonecro- Early diagnosis, emergency surgical debridement, sis (GFM) both represent subtypes of severe necrotiz- and wide-spectrum antibiotic therapy are the most ing soft tissue infections which share certain simi- effective treatment options to minimize the bacterial larities in their clinical presentation. However, both load and mortality rate associated with these condi- life-threatening infections have to be differentiated tions. Simple laboratory markers are helpful to detect with respect to the pathophysiology, clinical course life-threatening infection. The laboratory risk indica- and therapeutic consequences. NF initially presents tor for necrotizing fasciitis (LRINEC) score (3–5), with flue like symptoms, pain “out of proportion”, composed of the following six laboratory findings: local swelling and erythema which normally exceeds glucose level, c reactive protein level, white blood cell the one found in gas gangrene. Local symptoms are count, sodium level, creatinin level and haemoglobin, rapidly progressing, pathognomonic signs are dusky a combination of rapidly available laboratory param- and purplish patches with ill defined borders. Gen- eters has been designed to distinguish severe NSTI eralised features of septic shock like somnolence and from other soft tissue infections such as cellulitis. A hypotension may be present early after onset of the LRINEC score above six has been shown to be predic- infection. tive for an increased mortality and higher rate of am- In 1979, Fisher described seven diagnostic param- putations. eters (1): Extensive fascial necrosis involving the In general, mortality rates vary from 30 to 70%, overlaying skin, systemic septic involvement with which may even increase significantly if the infection reduced mental status, lack of a primary muscle in- progresses to myonecrosis (6–9). The aim of the fection, missing clostridium infection, lack of vascu- present study is to demonstrate the diagnosis, the lar occlusion, and finally a leukocyte infiltration with management and outcome of patients with NF and focal fascial necrosis and microthromboses as histo- GFM. logical findings. Purple, dark skin coloration and skin necrosis are signs of late stage of the disease. The infection prima- Material and Methods rily does not affect the musculature, muscular in- volvement is a sign of advanced stage of the infection For the retrospective analysis of all patients with NSTI the associated with poorer prognosis. As in clostridial database of the authors’ hospital was searched for all pa- gas gangrene signs of systemic infection with reduc- tients admitted to our institution suffering from severe soft- tion in mental status and deterioration of the general tissue infections between January 2005 and December 2009. During this period 30 patients (17 female/13 male) with NF status of the patient are found early in the course of and six patients with non clostridial gas-forming myone- the disease. In contrast to clostridial infections mini- crosis (3 female/3 male) were treated at the BG-University Hospital Bergmannsheil (Table 1). Medical records, histo- logical slides, microbiological specimens, Computed To- Table 1 mography (CT) and Magnetic resonance imaging (MRI) scans were reviewed for all patients. In all patients, the MeSh codes for patients with necrotizing soft tissue infection and non clostridial gas-forming myonecrosis. event leading to the infection, the site of infection, comor- bidities, the total number (including debridement and re- MeSh codes constructive surgery) and kind of surgical interventions as well as the duration of hospitalisation were recorded. The Necrotizing soft tissue infection C01.252.825.340 causative microorganisms isolated from tissue culture were C05.321.550 determined and the mortality rate was estimated. Non clostridial gas-forming myonecrosis The clinical diagnosis of necrotizing fasciitis was made C01.252.410.222.440 by attending surgical physicians, whereas clinical suspicion C23.550.325.500 was validated via histological examinations. Histologically, C23.550.717 necrotizing fasciitis was diagnosed when necrosis of the su- G04.299.139.638 perficial fascia, a polymorphonuclear infiltrate, and edema C05.651.594 of the reticular dermis, subcutaneous fat and superficial C10.668.491.562 fascia were present. A severe necrotizing infection affecting  Characteristics and differences in necrotizing fasciitis and gas forming myonecrosis: a series of 36 patients 53 the superficial fascial layer and the surrounding soft tissue Table 2 was confirmed histologically (10) in all but two cases, in LRINEC (laboratory risk indicator for necrotizing fasciitis) score. which no histological specimens were obtained. The clinical diagnosis of gas forming myonecrosis was Laboratory Parameter Score also made clinically by the attending surgical physicians. Clinical suspicion was confirmed via histological examina- C-reactive protein (mg/l) tions. The histological image of a severe myositis or my- < 150 0 onecrosis in conjunction with the clinical evidence of gas 150 or more 4 entrapment with in the musculature confirmed the diag- Total white cell count (per mm3) nosis of GFM. Gas forming myonecrosis was also evident < 15 0 on X-ray or CT scan. In all operated patients necrotizing 15–25 1 myonecrosis with gas entrapments was confirmed on his- > 25 2 tological assessment. Hemoglobin (g/dl) Additionally, the l aboratory risk indicator for necrotiz- > 13.5 0 ing fasciitis (LRINEC-) score in the initial diagnosis of NF 11–13.5 1 and GFM were calculated in all patients on admission. The < 11 2 LRINEC score is a calculation of a numerical score based on Sodium (mmol/l) the rapidly available laboratory parameters glucose level, 135 or more 0 C-reactive protein level, leucocyte count, NA, creatinin < 135 2 level, hemoglobin. The maximum score is 13, while a score Creatinine (mmol/l) ≥ 6 is suspicious for NF and a score ≥ 8 strongly predictive 141 or less 0 for NF (3–5) (Table 2). > 41 2 Aggressive physiological support to correct fluid defi- Glucose (mmol/l) cits, including electrolyte imbalances, extensive operative 10 or less 0 debridement and antiseptic wound dressing changes using > 10 1 sterile gauzes and wide-spectrum antibiotic therapy were the therapeutic strategy in all patients. Radical surgical debridement was required in almost every case prior to soft tissue closure. quent isolated bacterium was Staphylococcus aureus with seven cases (23%) followed by Streptococcus Statistical analysis pyogenes with five cases (17%). The mean length of hospital stay was 28 days (SD All variables were expressed in terms of mean and ± stan- 19.4) in all patients, while survivors stayed signifi- dard deviation (SD) of the mean. The t test was performed cantly longer in the hospital compared to deceased when the data were distributed normally; otherwise the patients (p = 0.002). A mean of 4 (SD 2.7) surgical in- Mann-Whitney test was used. The Shapiro-Wilk normality terventions were necessary during the treatment pe- test was performed to test the null hypothesis that the data had a normal distribution. For all tests, P < 0.05 was consid- riod (Table 3). Survivors underwent significantly ered statistically significant. The risk for mortality rate was more surgical interventions compared to deceased compared between the infection involving and not involv- patients (p = 0.03). Elevated laboratory parameters of ing the trunk using the odds ratio. Statistical analysis was acute infection with leukocyte counts (15.4 mm3 SD carried out by means of a statistical software package 6.8) and C-reactive protein levels (28,2 mg/dl SD (GraphPad Prism Version 4.1, GraphPad Software Inc., La 16.9) were present in all patients. The mean LRINEC Jolla, CA). Figures:score was 7.3 (SD 2.2). There was no statistically sig- nificant difference between survivors and deceased patients comparing the LRINEC score (n.s.) (Fig. 2). Results Necrotizing fasciitis (NF) Thirty patients (17 female, 13 male) with necrotizing fasciitis with a mean age of 55 years (SD 14.6) were included in the study. In fifteen cases (50%), the infec- tion was localized at the lower extremity followed by the upper extremity with 13 cases (43.3%) and trunk with two cases (6.7%). In the majority of cases (12 cases), minor skin lesions (Fig. 1) were identified as the site of origin. In the remaining cases, NF resulted from postoperative wound infections (3 cases), pre- existing abscesses (3 cases), bursitis (one case) and cat bite (one case). No cause was identified in ten pa- tients. A total of 17 patients (57%) had at least two co- morbidities. Diabetes mellitus was the most fre- quently observed co-morbidity present in 12 patients (40%) of all patients. A polymicrobial infection was found in eight patients (27%). No microorganism Figure 1..A Fig. r1.clinical presentation A r clinical of a necrotizing presentation soft tissue of a necrotizing infection. soft tissue The cause of infection. could be identified in 12 cases (40%). The most fre- NSTI The was cause of NSTI was a minor a minor skin lesion- skin lesion- HUOM: KUVA JULKAISTAAN MUSTAVALKOISENA. JOS HARMAASÄVYILLÄ SELVITETTÄISI SÄVYEROJA , MITÄ LUULET? Muistaakseni kokeilin mv:nä silloin kun vanha kone oli henkihieveriä- kuva naäytti ihan hyvältä.  54 D. J. Tilkorn, M. Citak, T. Fehmer, A. Ring, J. Hauser, S. Al Benna, L. Steinstraesser, B. Roetman, H.-U. Steinau Table 3 infection was secondary to major surgery (one biaor- Average age, gender ratio, LRINEC score, mean length of hospital stay, tofemoral vascular bypass, one peritonitis after a per- mean number of surgical interventions and mortality rate of all forated gangrenous appendicitis, one infected hip patients presenting between 2005 and 2009. arthroplasty). Three patients presented with intra- abdominal lesions (one anastomosis dehision after NSTI GFM 55 (31–87) 61.5 (45–80) rectal resection due to rectum carcinoma, one with a perforated sigmoid diverticulum and the before men- Age tioned peritonitis following appendectomy). In the Gender latter two patients the infection spread through the Male 13 3 sciatic foramen into the thigh. Female 17 3 The patients underwent an average of 3.5 (SD 3) LRINEC score 7.3 (2–10) 8.5 (8–10) surgical interventions. High levels of C-reactive pro- Mean length of hospital stay 28 (1–79) 29.3 (1–46) tein levels (29.8 mg/dl; SD 9.1) and leukocyte counts (days) (21.8 mm3; SD 8.2) were also present on admission. Mean number of surgical 4 (1–10) 3.5 (1–7) The mean LRINEC score was 8.5 (SD 1). The infection interventions was polymicrobial in two patients (33.3%), while the Mortality rate (%) 30 50 most frequent observed bacterium was Enterococcus faecium in two cases (33%). On average the patients were hospitalised for 29.3 days (SD 18). Three pa- tients (50%) died due to GFM. All patients were secondarily referred to our de- partment with the tentative diagnosis of NSTI. Surgi- cal debridement commenced 2.5 hours (SD 1.8) after admission to our department. Surgical debridement consisted of resection of the skin, subcutaneous tis- sue, the fascial layer and necrotic muscle tissue if affected. Discussion The most important findings of this study are that in the majority of cases with NF, minor skin lesions were identified as the site of origin in contrast to patients with GFM. GFM was frequently associated with an intraabdominal pathology or secondary to major sur- gical trauma. Diabetes mellitus is the most common comorbidity in patients with NF whereas patients with GFM had a high incidence of malignancy. Clin- Fig. 2. The LRINEC score for survivors and deceased patients with ically NF was a frequently observed to be an ascend- NSTI. There was no statistically significant difference between these groups. ing infection in constrast to GFM which presented as e 2 - The LRINEC score for survivors and deceased patients with NSTI. There a descending infection in all cases. Furthermore, pa- tients who had secondary involvement of the trunk was no statistically significant difference between these groups. had a higher mortality rate. The lowest LRINEC score in deceased patients was In general, necrotizing fasciitis is an insidious rap- six and in survivors two. Twenty-five out of 30 pa- idly progressing infection leading to necrosis of fas- tients (83.3%) had a LRINEC score ≥ 6. Only in five cial layer. Due to anatomical borders the infection patients (16.7%), the LRINEC score was < 6. Five pa- spreads along the fascial planes. During the initial tients required major amputation of the affected ex- phase NF maybe mistaken for cellulitis but prompt tremity. Patients with necrotizing soft tissue infection diagnosis is warranted (11). secondarily involving the trunk had a significantly Most of the time it is caused by a mixed aerobic/ higher mortality rate (OR 11.2; 95% CI = 1.7–72.3). anaerobic bacterial infection. Only in a subset of cases a streptococcal group A infection is present. Mortality Gas forming myonecrosis (GFM) rates from 30 to 70% are described in the literature, which may even increase significantly if the infection Six patients (female n = 3; male n = 3) with a mean age progresses to myonecrosis (6–9). However, in a recent of 61.5 years (SD 12.2) with non-clostridial gas form- study, Mills et al. reported a lower mortality rate with ing infection of the soft tissue were identified (Table 12% in 688 patients with NSTI (12). 3). In five cases (83%) the infection was located in the NSTI remains primarily a clinical diagnosis (7, 9). lower extremity. None of the patients had diabetes Several diagnostic measures such as the finger test, mellitus. Three patients had a history of malignancy probe biopsy and frozen sections as well as ultra- (rectal carcinoma, renal carcinoma, sarcoma). In two sound have been proposed as being useful adjuncts of these three patients metastatic disease was diag- for early recognition of NSTI (2, 7, 13–18). CT and nosed after onset of infection. In three patients the MRI scans are considered dispensable and might de-  Characteristics and differences in necrotizing fasciitis and gas forming myonecrosis: a series of 36 patients 55 lay the essential surgical intervention unnecessarily. Acknowledgement With a fast and thorough surgical debridement in NF limb amputations can often times be avoided (19), The authors thank Dr. Ingo Stricker, M.D., Depart- whereas in gas gangrene with clostridial myonecrosis ment of Pathology, BG University Hospital Bergmann- limb salvage is seldom feasible, rather the amputa- sheil, Ruhr University Bochum, Bochum, Germany, tion in these cases has to be considered a possibly life for his support with the histological assessment. saving treatment option. Therapeutical strategies in patients with necrotiz- References ing soft tissue infections are early recognition fol- lowed by a through surgical debridement eliminating 01. Fisher JR, Conway MJ, Takeshita RT et al: Necrotizing fasciitis. entire infected tissue (cutis/subcutaneous tissue, fas- Importance of roentgenographic studies for soft-tissue gas. JAMA 1979;241:803–806 cial layer and if affected musculature), an organism 02. Singh G, Sinha SK, Adhikary S et al: Necrotising infections of specific antibiotic regiment is the therapy of choice. soft tissues – a clinical profile. Eur J Surg 2002;168:366–371 Early enteral feeding, fluid resuscitation and an ad- 03. Su YC, Chen HW, Hong YC et al: Laboratory risk indicator for equate intensive care treatment to overcome the necrotizing fasciitis score and the outcomes. ANZ J Surg 2008; 78:968–972 symptoms of septic shock are corner stones of the 04. Wong CH, Khin LW: Clinical relevance of the LRINEC (Labo- treatment. Hyperbaric oxygen therapy has been de- ratory Risk Indicator for Necrotizing Fasciitis) score for assess- scribed as beneficial but its value in the therapy re- ment of early necrotizing fasciitis. Crit Care Med 2005; mains controversial (20). 33:1677 05. Wong CH, Khin LW, Heng KS et al: The LRINEC (Laboratory Previous studies have analyzed specific risk fac- Risk Indicator for Necrotizing Fasciitis) score: a tool for distin- tors, e.g. diabetes mellitus, obesity, peripheral vascu- guishing necrotizing fasciitis from other soft tissue infections. lar disease, age and female gender in patients with Crit Care Med 2004;32:1535–1541 necrotizing soft tissue infections (7, 21–23), while the 06. Rouse TM, Malangoni MA, Schulte WJ: Necrotizing fasciitis: most common risk factor was diabetes mellitus, a preventable disaster. Surgery 1982;92:765–770 07. Elliott DC, Kufera JA, Myers RA: Necrotizing soft tissue infec- which was also confirmed in our study. In contrast to tions. Risk factors for mortality and strategies for manage- NF diabetes mellitus was not observed in patients ment. Ann Surg 1996;224:672–683 with GFM. 08. Sudarsky LA, Laschinger JC, Coppa GF et al: Improved results In the presented study the LRINEC score proved from a standardized approach in treating patients with necro- tizing fasciitis. Ann Surg 1987;206:661–665 to be a useful adjunct in the diagnosis of severe soft 09. Wang KC, Shih CH: Necrotizing fasciitis of the extremities. tissue infection. Su et al. reported that patients with J Trauma 1992;32:179–182 a LRINEC score of ≥ 6 have higher rates of mortality 10. Stamenkovic I, Lew PD: Early recognition of potentially fatal and amputation (3). However, we did not find a sta- necrotizing fasciitis. The use of frozen-section biopsy. N Engl J Med 1984;310:1689–1693 tistical significant difference between deceased pa- 11. Schnall SB: Necrotizing fasciitis: clinical presentation, micro- tients and survivors for patients with NSTI. biology, and determinants of mortality. J Bone Joint Surg Am The incidence of GFM was very low and was en- 2004;86-A:869; author reply 869–870 countered in only six patients over the five year in- 12. Mills MK, Faraklas I, Davis C et al: Outcomes from treatment of necrotizing soft-tissue infections: results from the National terval. In contrast to NF, GFM originated either after Surgical Quality Improvement Program database. Am J Surg major surgery or had an underlying intraabdominal 200:790–796; discussion 796–797 source of infection. Four infections originated after 13. Andreasen TJ, Green SD, Childers BJ: Massive infectious soft- bowel perforation and one further case after retro- tissue injury: diagnosis and management of necrotizing fas- peritoneal surgery. None of these patients presented ciitis and purpura fulminans. Plast Reconstr Surg 2001;107: 1025–1035 with clinical signs of acute abdomen or peritonitis. 14. Wong CH, Wang YS: The diagnosis of necrotizing fasciitis. Unlike NF in GFM the infection was observed to Curr Opin Infect Dis 2005;18:101–106 spread distally. The mean age of the patients was 15. Majeski JA, John JF, Jr: Necrotizing soft tissue infections: a slightly above the age of NF patients. Three patients guide to early diagnosis and initial therapy. South Med J 2003; 96:900–905 had a previous history of malignancy, out of these 16. Walshaw CF, Deans H: CT findings in necrotising fasciitis – a three patients two were found to suffer from meta- report of four cases. Clin Radiol 1996;51:429–432 static disease, whereas none of the patients with NF 17. Wong CH, Chang HC, Pasupathy S et al: Necrotizing fasciitis: presented with an intra-abdominal pathology or pre- clinical presentation, microbiology, and determinants of mor- tality. J Bone Joint Surg Am 2003;85-A:1454–1460 vious history of malignancy. 18. Wysoki MG, Santora TA, Shah RM et al: Necrotizing fasciitis: CT characteristics. Radiology 1997;203:859–863 19. Majeski J, Majeski E: Necrotizing fasciitis: improved survival Conclusions with early recognition by tissue biopsy and aggressive surgical treatment. South Med J 1997;90:1065–1068 20. Mulla ZD: Hyperbaric oxygen in necrotizing fasciitis. Plast In conclusion, early diagnosis and extensive surgical Reconstr Surg 2008;122:1984–1985 debridement have been shown to improve the clinical 21. Asfar SK, Baraka A, Juma T et al: Necrotizing fasciitis. Br J outcome. In addition to a thorough clinical evalua- Surg 1991;78:838–840 tion by experienced clinicians, simple laboratory pa- 22. Hung CC, Chang SC, Lin SF et al: Clinical manifestations, microbiology and prognosis of 42 patients with necrotizing rameters can be helpful in the early detection of NSTI fasciitis. J Formos Med Assoc 1996;95:917–922 and GFM. Hence in our opinion early diagnostic 23. McHenry CR, Piotrowski JJ, Petrinic D et al: Determinants of measures such as CT or MRI scan to rule out an in- mortality for necrotizing soft-tissue infections. Ann Surg traabdominal process is warranted in these patients 1995;221:558–563; discussion 563–565 with descending gas forming infections to avoid a Received: March 1, 2011 delay in eradication of the infection. Accepted: November 8, 2011