Necrotizing soft tissue infections: are we making any progress?

Severe necrotizing soft tissue infections-Is wound microbiology a prognostic factor for clinical outcome?

Necrotizing soft tissue infections (NSTIs) represent similar pathophysiological features, but the clinical course might range from subacute to a rapidly progressive, fulminant sepsis. Initial wound microbiology is the base for the Guiliano classification. The timeline of microbiological colonization has not been described during the clinical course. The role of the different microbiological pathogens on the outcome and mortality is unclear. One hundred eighty patients were included with septic inflammation response syndrome on admission. Initial wound microbiology and the changes in wound microbiology were analysed during the clinical course and correlated with outcome and risk indicators. Overall mortality was 35%. Higher age, a high Charlson Comorbidity Index or ASA score and truncal infections were highly prognostic for a lethal outcome. Microbiological findings revealed significant differences in the persistence of bacteria during the course of disease. Streptococci were only detectable within the first 5 days, whereas other bacteria persisted over a longer period of time. Initial microbiological findings correlated with better prognosis when no causative agent was identified and for gram-negative rods. Varying survival rates were observed for different Streptococci, Staphylococci, Enterococci and other bacteria. The highest odds ratio for a lethal outcome was observed for Enterococci and fungi. Microbiological colonization changes during the clinical course of NSTIs and some microbiologic pathogens are predictive for worsening the outcome and survival. Streptococcus pyogenes is only detectable in the very early phase of NSTI and after 6 days not anymore detectable. Later Enterococci and fungi showed the highest odds ratios for a lethal outcome. Enterococci bacteria and fungi have yet not been considered of clinical relevance in NSTI or even as indicator for worsening the outcome.

Stenotrophomonas maltophilia Necrotizing Soft Tissue Infection in an Immunocompromised Patient

Introduction

To report on the first recorded case of necrotizing soft tissue infection (NSTI) in an immunocompromised individual caused by Stenotrophomonas maltophilia in the Western Hemisphere and highlight the challenges that medical providers face in promptly diagnosing and treating NSTI in this highly vulnerable patient population.

Case Presentation

We report a case of NSTI caused by S. maltophilia in a neutropenic patient admitted for treatment of acute lymphoblastic leukemia. The patient presented with laboratory and clinical findings atypical for a NSTI that may have confounded its diagnosis and delayed surgical intervention. Despite aggressive medical care and surgical debridement, the patient unfortunately passed away due to overwhelming septic shock.

Conclusions

Providers should consider atypical organisms as causative in NSTI in immunocompromised patients and recognize that these patients may present without classic clinical and laboratory findings.

Long-term follow-up of Fournier's Gangrene in a tertiary care center

BACKGROUND

After surgical debridement, the use of fecal diversion systems (such as an endo-rectal tube or surgical colostomy) in Fournier's Gangrene (FG) to assist with wound healing remains controversial.

METHODS

A 6-y retrospective review of a tertiary medical center emergency surgery database was conducted. Variables abstracted from the database include patient demographics, laboratory and physiological profiles, hospital length-of-stay, intensive care unit length-of-stay, operative data, time to healing, morbidity, and mortality.

RESULTS

Thirty-five patients were treated. Seventy-seven percent (n = 27) required some form of fecal diversion (21 patients using an endo-rectal tube and six patients undergoing construction of a surgical colostomy). One patient had a pre-existing colostomy before the development of FG. The remaining seven patients underwent conservative wound care with multiple daily dressing changes (no diversion system). Twenty-eight of the 35 patients (80.0%) had long-term follow-up with 100% having completely healed surgical wounds at the final clinic visit. Average time to complete wound healing was 4.8 ± 1.0 mo (range, 1.0-31.0). Of the six patients who underwent colostomy formation, two had their colostomies reversed, two were unacceptable surgical risk and did not undergo reversal (due to uncontrolled diabetes and cardiovascular disease), and two were lost to follow-up. Of the two patients who had their colostomies reversed both had complications from their reversal (leak and urinary retention).

CONCLUSIONS

Surgical colostomy may not be mandatory (and might be associated with a high additional morbidity) in FG. With appropriate patient selection, it may be possible to avoid colostomy formation using a less-invasive diversion technology without compromising patient outcomes.

Risk Stratification of Necrotizing Fasciitis Based on the Initial Procalcitonin Concentration: A Single Center Observational Study

BACKGROUND

Necrotizing fasciitis (NF) is a potentially fatal subcutaneous tissue and fascia infection. We studied the role of serum procalcitonin in the identification and assessment of severity of sepsis in patients with NF.

METHODS

A retrospective analysis was conducted from January 2000 to December 2013 for all patients who admitted to surgical intensive care with provisional diagnosis of NF. Patients were categorized into four groups based on the initial procalcitonin concentrations (Group I: <0.5 low risk, Group II: ≥0.5-<2 moderate risk, Group III: ≥2-<10 high risk, and Group IV: ≥10 ng/mL high likelihood of severe sepsis).

RESULTS

During the study period, 331 cases were identified to have NF with a mean age of 51 ± 14 years. Serum procalcitonin was tested in 62 cases (only between 2011 and December 2013) and all were positive (Group I: 22%, Group II: 18%, Group III: 21%, and Group IV: 39%). The most common affected regions were thigh and chest in Group II (46% and 9%, respectively), lower limbs in Group III (46%), and perineum and abdomen in Group IV (25% and 21%, respectively). In the four groups, 21 patients developed septic shock (Group I: 0%, Group II: 14%, Group III: 24%, and Group IV: 62%). The cut off procalcitonin value for septic shock was 5.6 ng/mL. Using receiver-operating characteristic curve, this cut off with the Area under the Curve (AUC) of 0.77 was found to have sensitivity 81% and specificity 67%. Sequential Organ Failure Assessment (SOFA) score was substantially greater in Group III and Group IV in comparison to Group I and Group II, p = 0.006. Procalcitonin levels were correlated well with SOFA score (r = 0.34, p = 0.007). There were 17 deaths in the four groups (Group I: 6%, Group II: 23%, Group III: 12%, and Group IV: 59%).

CONCLUSION

Initial procalcitonin concentration in NF carries an important prognostic value and it correlates well with SOFA score and can predict the development of septic shock early in patients with NF.

Necrotizing soft tissue infections after injection therapy: Higher mortality and worse outcome compared to other entry mechanisms

OBJECTIVES

Necrotizing Soft Tissue Infections represent a rare entity of infection associated with a high mortality. The aim of this retrospective study was to analyze patients with an iatrogenic etiology of injection or infiltration to compare the outcome with other etiologies.

METHODS

The study group consisted of 21 patients treated with a Necrotizing Fasciitis caused by injection or infiltration. Risk factors and outcome were compared to 134 patients with a Necrotizing Fasciitis caused by other entry mechanisms.

RESULTS

Overall mortality in our study group was 14 of 21 (67%) with an amputation rate of 11 of 15 (73%) if an extremity was involved. The survival rate was significantly worse after injection or infiltration (p < 0.001) as was the amputation rate (p = 0.013), the percentage of patients requiring intensive care (100% vs. 83%, p = 0.038) and vasopressors (81% vs. 54%, p = 0.02). Injection or infiltration therapy proved to be the strongest prognostic factor (p = 0.003) besides the known risk factors obesity (0.007) and renal insufficiency (0.025).

CONCLUSIONS

Our results demonstrate that patients with a Necrotizing Soft Tissue Infection after injection or infiltration therapy have a significantly worse prognosis.

A contemporary analysis of Fournier gangrene using the National Surgical Quality Improvement Program

OBJECTIVE

To determine a nationwide contemporary description of surgical Fournier gangrene (FG) and necrotizing fasciitis of the genitalia (NFG) outcomes because historically reported mortality rates for FG and NFG are based on small single-institution studies from the 1980s and the 1990s.

METHODS

The National Surgical Quality Improvement Program is a risk-adjusted surgical database used by nearly 400 hospitals nationwide, which tracks preoperative, intraoperative, and 30-day postoperative clinical variables. Data are extracted from patient charts by an independent surgical clinical reviewer at each hospital. Using the National Surgical Quality Improvement Program data from 2005 to 2009, we calculated 30-day mortality rates and identified preoperative factors associated with increased mortality.

RESULTS

A total of 650 patients were identified with surgery for FG or NFG. Fourteen patients with do not resuscitate orders placed preoperatively were excluded from analyses. For the remaining 636 patients, the overall 30-day mortality was 10.1% (64 of 636). Fifty-seven percent of patients (360 of 636) were men, 70% (446 of 636) were white, and 13% (81 of 636) were African American. Multivariate logistic regression indicated that increased age (odds ratio [OR], 1.041; P = .004), body mass index (OR, 1.045; P <.001), and preoperative white blood cell count (OR, 1.061; P = .001), and decreased platelet count (OR, 0.993; P <.001) were all associated with increased risk of death.

CONCLUSION

We determined a surgical mortality rate for FG-NFG of 10.1%. This rate is about half of historically published estimates and similar to recent studies. The lower rate may indicate improvements in therapy. Increased age, body mass index, and white blood cell count, and decreased platelet count were all associated with an increased risk of 30-day mortality.

Monomicrobial necrotizing fasciitis in a single center: the emergence of Gram-negative bacteria as a common pathogen

BACKGROUND

Necrotizing fasciitis (NF) is a life-threatening soft tissue infection. It is usually caused by Streptococcus pyogenes and other Gram-positive bacteria. Several reports, however, emphasize the importance of Gram-negative rods in this infection.

METHODS

We retrospectively studied all cases of monomicrobial necrotizing fasciitis hospitalized in our center during the years 2002-2012. We compared clinical characteristics and outcomes of patients with Gram-negative versus Gram-positive infection.

RESULTS

Forty-five cases were reviewed, 19 caused by Gram-negative organisms, 10 of them Escherichia coli, and 26 caused by Gram-positive organisms, 10 of them S. pyogenes. Compared to Gram-positive infections, patients with Gram-negative infections were more likely to have a baseline malignancy (9/19, 47.4%) or to have undergone recent surgery (4/19, 42.3%). The 30-day mortality was higher among Gram-negative infected patients (8/19, 42.1% vs. 8/26, 30.8%). Creatine phosphokinase (CPK) was elevated in a minority of patients with Gram-negative necrotizing fasciitis, and its absolute value was lower than in Gram-positive necrotizing fasciitis.

CONCLUSIONS

In our center, 42% of monomicrobial necrotizing fasciitis cases were found to be caused by Gram-negative organisms, mostly E. coli. These infections usually appeared in immunocompromised or postoperative patients, often presented with normal CPK levels, and were associated with high mortality rates.

Procalcitonin ratio as a predictor of successful surgical treatment of severe necrotizing soft tissue infections

BACKGROUND

Necrotizing soft tissue infections often are characterized by fulminant presentation and lethal outcomes. Besides critical care support and antibiotic therapy, aggressive surgical treatment is important for the therapy of necrotizing fasciitis. The aim of this study was to develop a procalcitonin (PCT) ratio indicating successful surgical intervention.

METHODS

The study group consisted of 38 patients treated with clinical signs of sepsis caused by a necrotizing soft tissue infection. All patients received radical surgical treatment, and serum levels of PCT and C-reactive protein were monitored postoperatively. The ratio of day 1 to day 2 was calculated and correlated with the successful elimination of the infectious source and clinical recovery.

RESULTS

An eradication of the infectious focus was successfully performed in 84% of patients, averaging 1.9 operations (range 1 to 6) to achieve an elimination of the infectious source. The PCT ratio was significantly higher in the group of patients with successful surgical intervention (1.665 vs .9, P < .001). A ratio higher than the calculated cutoff of 1.14 indicated successful surgical treatment with a sensitivity of 83.3% and a specificity of 71.4%. The positive predictive value was 75.8%, and the negative predictive value was 80.0%.

CONCLUSIONS

The PCT ratio of postoperative day 1 to day 2 following major surgical procedures for necrotizing soft tissue infections represents a valuable clinical tool indicating successful surgical eradication of the infectious focus.

Fournier's gangrene

Fournier's gangrene (FG) is a synergistic polymicrobial gangrenous infection of the perineum, scrotum and penis which is characterised by obliterative endarteritis of the subcutaneous arteries, resulting in gangrene of the subcutaneous tissue and the overlying skin. FG affects all ages and both genders, with a male preponderance. It is a rare but life-threatening disease, and despite therapeutic advances in recent years, the mortality rate is 3%-67%, with an incidence of 1:7500-1:750,000. Anorectal, genitourinary and cutaneous sources of infection are the most common causes of FG, with diabetes mellitus being the most common risk factor. The clinical condition presents evolution from 2 to 7 days and is characterised by uneasiness, local swelling and discomfort, fever, crepitus and sometimes frank septic shock. Current imaging techniques for initial evaluation of the disease include radiography, Ultrasonography (USG), Computed Tomography (CT) and Magnetic Resonance Imaging (MRI). However, the diagnosis of FG is usually clinical and imaging can be helpful in uncertain diagnosis and when clinical findings are ambiguous. Treatment of FG is based on a multimodal approach which includes intensive fluid resuscitation to stabilise the patient and correction of electrolyte imbalance, if any. This is followed by extensive debridements and resections in order to remove all necrotic and infected tissue, wide spectrum antibiotics and reconstructive surgery, whenever required. However, despite all the advances in treatment today, FG remains a surgical emergency, hence, early recognition with aggressive haemodynamic stabilisation, parenteral broad spectrum antibiotics and urgent surgical debridement are the mainstay of treatment.

Emphysematous osteomyelitis: a case report and review of the literature

We report the case of a 15-year-old girl with pelvic and sacral emphysematous osteomyelitis caused by Fusobacterium necrophorum. This infection was cured following four surgical procedures and 4 weeks of intravenous then 4 weeks of oral antibiotics. We review our case alongside the 24 previously reported cases of emphysematous osteomyelitis in the literature. The 25 cases include 15 monomicrobial and 10 polymicrobial infections. The causative organism(s) in all but three cases included an anaerobe or a member of the Enterobacteriaceae family. A significant underlying comorbidity was reported in 18 cases. At least 15 cases required one or more surgical procedures. There was a significant associated mortality with eight (32%) patients dying in hospital at 7 to 56 days after the diagnosis of emphysematous osteomyelitis.

Local variations in the epidemiology, microbiology, and outcome of necrotizing soft-tissue infections: a multicenter study

BACKGROUND

Necrotizing soft-tissue infections (NSTIs) are rare and highly lethal.

METHODS

A retrospective chart review of patients with NSTIs treated at 6 academic hospitals in Texas between January 1, 2004 and December 31, 2007. Patient demographics, presentation, microbiology, treatment, and outcome were recorded. Analysis of variance, chi-square test, and logistic regression analysis were performed.

RESULTS

Mortality rates varied between hospitals from 9% to 25% (n = 296). There was significant interhospital variation in patient characteristics, microbiology, and etiology of NSTIs. Despite hospital differences in treatment, primarily in critical care interventions, patient age and severity of disease (reflected by shock requiring vasopressors and renal failure postoperatively) were the main predictors of mortality.

CONCLUSIONS

Significant center differences occur in patient populations, etiology, and microbiology of NSTIs, even within a concentrated region. Management should be based on these characteristics given that adjunctive treatments are unproven and variations in outcome are likely because of patient disease at presentation.

The use of extracorporeal membrane oxygenation in severe necrotizing soft tissue infections complicated by septic shock

Necrotizing soft tissue infections remain a challenging clinical problem. Delays in diagnosis, incomplete débridement of necrotic tissues, and the hemodynamic instability and end-organ failure associated with overwhelming sepsis all contribute to significant mortality. Extracorporeal support is a well-established tool to support profound cardiopulmonary failure. To broaden the indications for use, we present two cases of young adults with necrotizing soft tissue infections who sustained sepsis-induced hemodynamic collapse and required extracorporeal support to facilitate adequate tissue débridement as a bridge to recovery.

Fascitis necrosante por Streptococcus pyogenes

Necrotizing fasciitis is a severe infection, with systemic involvement and tissue necrosis. The clinical course is rapid and often fatal. Although this entity is uncommon, early recognition and treatment is essential to improve prognosis. Necrotizing fasciitis should be suspected when there are symptoms of toxicity and there is severe pain, frequently out of proportion to the clinical findings. In addition, in the last few years the incidence of invasive disease due to Streptococcus pyogenes in children has increased. Treatment is based on life support, aggressive debridement, and antimicrobial therapy. Intravenous immunoglobulin (IVIG) as adjunctive therapy seems useful and reduces mortality. The case of an infant with necrotizing fasciitis of four extremities is presented.

The Impact of Diabetes in Patients with Necrotizing Soft Tissue Infections

BACKGROUND

Given the association of diabetes with necrotizing soft tissue infections (NSTIs) and hyperglycemia with mortality in critically ill patients, this study investigates the impact of diabetes and hyperglycemia in NSTI patients.

METHODS

This is a retrospective review of NSTI patients at LBJ General Hospital between January 1995 and December 2002, assessing infectious morbidity, mortality, and length of hospital stay.

RESULTS

There was a trend towards increased infectious complications, defined as a hospital-acquired (not present within 48 h of presentation) infection at a secondary site, amongst diabetic patients (RR 2.1, 95% CI 0.7-6.8) and patients with admission hyperglycemia greater than 200 mg/dL (OR 1.9, 95% CI 0.7-5.7) but not with admission hyperglycemia greater than 120 mg/dL (OR 1.6, 95% CI 0.3-8.7). Patients with an infectious complication had a longer hospital stay (median, interquartile range [IQR]; 36, 30-44 days vs. 10, 7-20 days, p < 0.001), increased mortality (29% vs. 7%, p = 0.05), and poorer outcome defined as death, amputation, or hospital stay exceeding the 75th percentile for length of stay (79% vs. 20%, p < 0.001).

CONCLUSIONS

Diabetes mellitus and admission hyperglycemia may increase infectious complications in NSTI patients, predicting a longer and more complicated hospital course. Further study is required to define the optimal metabolic target in this patient population.

Fournier's gangrene

Fournier's gangrene can still be a life-threatening condition with a high mortality rate. Diagnosis and treatment should be prompt and adequate. Radiological studies may help to define the extent of the disease preoperatively in cases in which this is unclear. Surgery with extensive debridement of all necrotic tissue is the mainstay of treatment.