NECROTIZING FASCIITIS

RISK FACTOR :

have not been identified 

*Conditions associated with necrotizing infection include drug use, diabetes mellitus, obesity, and immunosuppression .

DIAGNOSIS 

Clinical symptom : fever, tachycardia, and hypotension, tense edema outside the involved skin, disproportionate pain, blisters/bullae, crepitus, and subcutaneous gas .

*These findings, although fairly specific, have a low sensitivity of 10 to 40 percent

6 common laboratory parameters

• Serum C-reactive protein ≥150 mg/L (4 points)
• White blood cell count 15,000 to 25,000/microL (1 point) or >25,000/microL (2 points)
• Hemoglobin 11.0 to 13.5 g/dL (1 point) or ≤11 g/dL (2 points)
• Serum sodium less than 135 meq/L (2 points)
• Serum creatinine greater than 1.6 mg/dL (141 micromol/L) (2 points)
• Serum glucose greater than 180 mg/dL (10 mmol/L) (1 point)

 ≥6 should raise the suspicion for necrotizing fasciitis 

 ≥8 was highly predictive (>75 percent).

*Necrotizing fasciitis, 75 to 80 percent had a score ≥8

*while only 7 to 10 percent had a score less than 6

IMAGING 

Non-contrast CT :GAS in the tissue, seen in type I necrotizing fasciitis or gas gangrene caused by clostridia 

* Sometimes only soft tissue swelling was found , in trauma, postsurgical or postpartum patient
* MRI can be overly sensitive

CLASSIFICATION
Type I:

• 2/3 had mixed aerobic and anaerobic bacteria(there were an average of 4.6 isolates per specimen) 
• Staphylococcus aureus, streptococci, enterococci, Escherichia coli, Peptostreptococcus species, Prevotella and Porphyromonas species, Bacteroides fragilis group, and Clostridium species
• DM present in 18 and 71 %

Type II :

• GAS  or MRSA

Compare :

Clinical finding	Type I*	Type II*	Gas gangrene	Pyomyositis	Myositis viral/parasitic
Fever	++	++++	+++	++	++
Diffuse pain	+	+	+	+	++++(1)
Local pain	++	++++(2)	++++	++	++
Systemic toxicity	++	++++	++++	+	+
Gas in tissue	++	-	++++	-	-
Obvious portal of entry	++++	±(3)	++++(4)	-	-
Diabetes mellitus	++++	±	-	-	-

* Type I and type II refer to the forms of necrotizing fasciitis; spontaneous gangrenous myositis is type II.
1. Pain with influenza consists of diffuse myalgia; pleurodynia may be associated with severe, localized pain (eg, devil's grip); pain with trichinosis may be severe and localized.
2. Severe pain is associated with necrotizing fasciitis due to group A streptococcal infection; the pain may not be severe in type I necrotizing fasciitis because is commonly associated with diabetes with neuropathy.
3. 50 percent of patients with necrotizing fasciitis due to group A streptococcal infection do not have an obvious portal of entry.
4. Gas gangrene associated with trauma may be caused by Clostridium perfringens, C. septicum, or C. histolyticum which always have an obvious portal of entry; in comparison, spontaneous gas gangrene caused by C. septicum usually does not have an obvious portal of entry - organisms lodge in tissue as a result of bacteremia originating from a bowel portal of entry.

TREATMENT


Surgery:

The best indication for surgical intervention :
  severe pain, toxicity, fever and elevated CPK with or without radiographic findings
*Delay in surgical will increases mortality

Antibiotic:
Type1:

•  Early empiric treatment : ampicillin-sulbactam(Unacyn) or ampicillin + clindamycin or metronidazole
•  Prior hospitalization or if antibiotics have been used recently : substituting ticarcillin-clavulanate(Timentin) or piperacillin-tazobactam(Tazocin) for ampicillin-sulbactam or by adding a fluoroquinolone, an aminoglycoside, an extended spectrum cephalosporin, or a carbapenem

Type2 :

• Initial empiric should cover both GAS and MRSA/CA-MRSA

*for GAS :Penicillin G (4 million units intravenously every four hours in adults >60 kg in weight and with normal renal function) in combination with Clindamycin (600 to 900 mg intravenously every eight hours)
*for MRSA: Vancomycin

HBO:
Indication : Infection such as clostridial myonecrosis (gas gangrene), necrotizing fasciitis
*patients with clostridial myonecrosis, HBO may reduce mortality and better define necrotic tissue.

IVIG:
Necrotizing fasciitis due to group A streptococcus (GAS/Type II) complicated by streptococcal toxic shock syndrome(TSS), the addition of IVIG can be considered
*although the data are not sufficient to provide a strong recommendation for IVIG in this setting

FLUID/BLOOD SUPPLY:


Streptococcal(TSS) toxic shock syndrome, massive amounts of intravenous fluids (10 to 20 L/day) are often necessary to maintain

• Dopamine may be useful, but there is little information of their efficacy in this setting. 
• Epinephrine and norepinephrine, may improve blood pressure but symmetrical gangrene is a common complication in our experience 

Mortality:

• 21 %in type I necrotizing fasciitis 
• 14 to 34 % in type II necrotizing fasciitis in which streptococcal toxic shock syndrome 

附錄:

GAS TSS DISGNOSIS :

• Isolation of GAS from a normally sterile site (eg, blood cerebrospinal, pleural, or peritoneal fluid, tissue biopsy, or surgical wound) plus
• Hypotension (systolic blood pressure ≤90 mm Hg in adults or <5th percentile for age in children)

plus two or more of the following:

• Renal impairment (creatinine in adults, ≥2 mg/dL; in children, two-times upper limit of normal for age; in patients with pre-existing renal disease ≥ twofold elevation over baseline)
• Coagulopathy (eg, thrombocytopenia, disseminated intravascular coagulation)
• Liver involvement (eg, ≥ two-times upper limit of normal for age of transaminases or bilirubin; in patients with pre-existing liver disease ≥ twofold elevation over baseline)
• Adult respiratory distress syndrome
• Erythematous macular rash, may desquamate
• Soft tissue necrosis (eg, necrotizing fasciitis, myositis, or gangrene)