Necrotizing soft tissue infections: Difference between revisions

Revision as of 02:12, 5 September 2013

Includes necrotizing forms of cellulitis, myositis, and fasciitis
Two types:
- Type 1: polymicrobial infection
- Type 2: group A strep
  - May occur in healthy individuals
  - May occur via hematogenous spread from throat to site of blunt trauma

Surgical exploration is the ONLY way to definitively establish the diagnosis of necrotizing infection
Imaging
- Should not delay surgical exploration
- CT is study of choice

May use to risk stratify patients p/w signs of cellulitis to determine likelihood of necrotizing fasciitis
Score based on: CRP, WBC, Hb, Na, Cr, Glucose
Score > 6 has PPV of 92% and NPV of 96% for necrotizing fasciitis
- Be aware LRINEC score has not been prospectively validated, index of suspicion is key

Surgical exploration and debridement
- Indicated in setting of severe pain, toxicity, fever, elevated CK (w/ or w/o radiographic evidence)
Abx
- Must cover Gram +/- and anaerobes (esp GAS and clostridium)
- Piperacillin-tazobactam 3.375-4.5g q6hr AND clindamycin 600-900mg q8hr AND vancomycin 1gm IV q12hr

Much rarer than nec fasc
May be preceded by skin abrasions, blunt trauma, heavy exercise
Most patients are otherwise healthy (DM and other underlying conditions do not appear to increase risk)

Exquisite pain and swelling of affected muscle with induration
Overlying skin changes may manifest later in the course of illness (erythema, warmth, petechiae, bullae)
Hypotension may occur rapidly with development of streptococcal toxic shock syndrome

Trauma
Surgical contamination
Spread of infection from bowel to perineum, abdominal wall, or lower extremities

Thin, dark, sometimes foul-smelling wound drainage (often containing fat globules)
Tissue gas formation (crepitus)

Authors:

@@ Line 42: / Line 42: @@
 **Should not delay surgical exploration
 **CT is study of choice
+====Laboratory Risk Indicator for Necrotizing Fasciitis (LRINEC) Score (Wong et al)====
+*May use to risk stratify patients p/w signs of cellulitis to determine likelihood of necrotizing fasciitis
+*Score based on: '''CRP, WBC, Hb, Na, Cr, Glucose'''
+*Score > 6 has PPV of 92% and NPV of 96% for necrotizing fasciitis
+**Be aware LRINEC score has not been prospectively validated, index of suspicion is key
+#CRP (mg/L) ≥150: 4 pts
+#WBC count (x10<sup>3</sup>/mm<sup>3</sup>):
+##<15: 0 pts
+##15-25: 1 pt
+##>25: 2 pts
+#Hb (g/dL):
+##>13.5: 0 pts
+##11-13.5: 1 pt
+##<11: 2 pts
+#Na (mmol/L) <135: 2 pts
+#Cr (mg/dL) >1.6: 2 pts
+#glucose (mg/dL) >180: 1 pt
 ===Treatment===