Diagnostics

No laboratory markers specific for FG exist, although some serum studies assist in determining the extent of systemic involvement and provide biomarkers for prognosis, including: a comprehensive metabolic panel (which may reveal hyponatremia) and elevations of white blood cells, C-reactive protein, erythrocyte sedimentation rate, and lactate.4, 7,8, 13 Some studies have discussed that a white blood cell count >15,400 cells/µL and serum sodium <135 mEq/L significantly increases the likelihood of necrotizing infections, with the recognition that these laboratory studies have greater negative predictive value than positive predictive yield.8  Some providers therefore advocate the use of various scoring instruments, of which laboratory analysis is of great significance.One such instrument is the laboratory risk indicator for necrotizing fasciitis (LRINEC), which is used to distinguish between necrotizing and non-necrotizing soft tissue infections by assigning points to laboratory findings in patients with suspected severe soft tissue infections to create a score that stratifies risk (Table 2).The utility of the score is dependent on a clinician’s high index of suspicion.8

When FG is suspected, blood and wound cultures should be obtained early so that appropriate antibiotics may be selected according to the susceptibility of the causative organism(s). Computed tomography (CT) with IV contrast is the preferred modality to confirm diagnosis across specialties, owing in large part to its availability and reliability in guiding surgical management.11,17,18 CT with IV contrast is able to reveal the path of disease, extent of inflammation, fascial thickening, formation of emphysema, fluid collection, and fat stranding.11,17,18 While magnetic resonance imaging with IV contrast offers benefits similar to CT, many clinicians regard this imaging modality as impractical in the emergent setting given resource limitations and challenges in obtaining reliably. It has been proposed that diagnosis of FG may be confirmed with bedside ultrasound, which can reveal the presence of subcutaneous gas. However, this is neither specific nor sensitive, as the absence of subcutaneous emphysema does not rule out FG and has the added limitation of being examiner dependent when used at the bedside.11 Table 3. Common Antimicrobial Agents for Treatment of Fournier Gangrene10,12

Table 2. Laboratory Risk Indicator for Necrotizing Fasciitis*
Laboratory ValuePoints
C-reactive protein (mg/L)
<150
>150

0
4
White blood cell count (cells/µL)
<15
15-25
>25

0
1
2
Hemoglobin (g/dL)
<11
11-13.5
>13.5

0
1
2
Sodium (mEq/L)
≥135
<135

0
2
Creatinine (mg/dL)
≤1.6
>1.6

0
2
Glucose (mg/dL)
≤180
>180

0
1

*The LRINEC scoring system is used only for those patients with a suspected or diagnosed soft tissue infection. A total score >6 implies intermediate- and high-risk patients.8

Treatment
FG historically has been a urologic emergency, with early surgical intervention being the cornerstone of mortality reduction.7,9,10 Conventional practice has allowed an interdisciplinary approach that includes both plastic and general surgery. Considering multiple provider consultations in the management of FG is essential to success and may include supportive inpatient medical management by a hospitalist and an infectious disease specialist. 2,3,11  A number of antibiotic regimens that can halt disease progression may be administered preoperatively, although they are not meant to substitute or delay surgical intervention.7,10 Generally, the regimen should cover polymicrobial sources including gram-positive, gram-negative, aerobic, and anaerobic organisms, with consideration for emerging multidrug-resistant strains.2,10,15 Suitable regimens might include a combination of some or all of the following: an aminoglycoside, metronidazole, piperacillin/tazobactam, clindamycin, vancomycin, and/or a third-generation cephalosporin (Table 3).2,10 Clindamycin remains one of the preferred first-line agents, due in large part to its role in reduction of mortality through coverage against toxin-producing organisms including streptococcal and clostridial species.15 Those with progressive disease, including septic shock, will require fluid restoration and vasopressors. Hyperbaric therapy has been proposed for management of FG to improve oxygenation to the tissues and increase healing times.2,7,9

Table 3. Common Antimicrobial Agents for Treatment of Fournier Gangrene10,12

Drug Class Name Brand Name
Third-generation cephalosporins Ceftriaxone Rocephin®
Aminoglycosides Amikacin Amikin®
Nitroimidazoles Metronidazole Flagyl®
β-lactamase inhibitors Piperacillin-tazobactam Zosyn®
Lincosamides Clindamycin Cleocin®

Prevention

Many of the risk factors associated with FG are preventable. Of the common comorbidities, alcohol use and hyperglycemia remain those most associated with morbidity and mortality.2,9,11 Simple measures of glycemic and hypertension control along with weight loss have been proposed as key factors for prevention. Numerous studies have been conducted to determine the role of the most common comorbidities in provoking FG, especially those deemed largely preventable.4,6,12 For example, some studies determined that glycosylated hemoglobin levels >7% or uncontrolled diabetes present the greatest risk.4,6,12,18  Similar studies were unable to consistently substantiate the correlation between uncontrolled diabetes and mortality, instead favoring other prognostic indicators such as chronic kidney disease (CKD), in particular CKD requiring hemodialysis.19-22 Despite these findings, strict conventional glycemic control as a means of risk reduction is strongly recommended.

Prevention of FG should not be limited to outpatient strategies alone. During the course of the patient’s hospital stay and recovery, further care should be taken to reduce the hazards of additional trauma from procedures that could result in FG, particularly those to the gastrointestinal and genitourinary tracts.9,10,11 If trauma to the perineum has occurred, patients and healthcare professionals should be encouraged to clean the affected sites frequently, continue proper hand washing techniques, and remain vigilant for any signs of disease.23 Patients should be informed that if signs of infection manifest, prompt recognition and management should be sought.23