Necrotizing soft tissue infection: Difference between revisions

Revision as of 09:36, 8 March 2021

Background

Microbiology

See Classification, below
Most commonly caused by monomicrobial Streptococcus pyogenes, Staphylococcus aureus, Clostridium species, or Vibrio species, or polymicrobial infections that include Gram-positives, Gram-negatives, and anaerobes

Classification

Although it is classically divided into Type 1 (polymicrobial) and Type 2 (monomicrobial), others have proposed an extension to include Type 3 (water-associated monomicrobial) and Type 4 (fungal).
Type 1: polymicrobial, including Staphylococcus aureus, Gram-negative bacilli, and anaerobes
Type 2: monomicrobial Gram-positive infections, primarily Streptococcus pyogenes (most common) but also Staphylococcus aureus or Clostridium (penetrating trauma, soil exposure)
Type 3: monomicrobial Gram-negative infections, generally caused by water-associated Vibrio vulnificus or Aeromonas hydrophila
Type 4: fungal, caused by Candida species, and exceedingly rare

Management

Surgical debridement!
Empiric antibiotics
- Piperacillin-tazobactam
- Clindamycin, for synergy and the Eagle phenomenon and decreased toxin production
- +/- vancomycin
Then narrow based on the Gram stain an culture
Can consider IVIg, rarely, in toxic shock syndrome

Eagle Effect

Originally, referred to decreased effectiveness of penicillins at high concentrations
Now, refers to decreased effectiveness of penicillins at high bacterial burden (when in stationary phase)
Clindamycin kills enough of the bacteria that are in stationary phase that the bacteria return to logarithmic growth phase, where penicillins are more effective

@@ Line 1: / Line 1: @@
-== Classification ==
+== Background ==
+=== Microbiology ===
-Although it is classically divided into Type 1 (polymicrobial) and Type 2 (monomicrobial), others have proposed an extension to include Type 3 (water-associated) and Type 4 (fungal).
+* See Classification, below
-* '''Type 1:''' polymicrobial, including ''[[Staph. aureus]]'', [[Gram-negative bacilli]], and [[anaerobes]]
+* Most commonly caused by monomicrobial [[Streptococcus pyogenes]], [[Staphylococcus aureus]], [[Clostridium species]], or [[Vibrio species]], or polymicrobial infections that include Gram-positives, Gram-negatives, and anaerobes
-* '''Type 2:''' monomicrobial [[Group A Streptococcus]] (''Strep. pyogenes'')
-** May include ''[[Staph. aureus]]'', ''[[Clostridium]]'' (penetrating trauma, soil exposure), ''[[Vibrio]]'' (water), ''[[Aeromonas]]'' (water)
-* '''Type 3:''' monomicrobial Gram-negative infections, generally caused by water-associated ''[[Vibrio vulnificus]]'' or ''[[Aeromonas hydrophila]]''
-* '''Type 4:''' fungal, caused by ''[[Candida]]'' species, and exceedingly rare
+===Classification===
-== Management ==
+* Although it is classically divided into Type 1 (polymicrobial) and Type 2 (monomicrobial), others have proposed an extension to include Type 3 (water-associated monomicrobial) and Type 4 (fungal).
-* Surgical debridement!
+* '''Type 1:''' polymicrobial, including [[Staphylococcus aureus]], [[Gram-negative bacilli]], and [[anaerobes]]
-* Empiric antibiotics
+*'''Type 2:''' monomicrobial Gram-positive infections, primarily [[Streptococcus pyogenes]] (most common) but also [[Staphylococcus aureus]] or ''[[Clostridium]]'' (penetrating trauma, soil exposure)
-** [[Piperacillin-tazobactam]]
+*'''Type 3:''' monomicrobial Gram-negative infections, generally caused by water-associated ''[[Vibrio vulnificus]]'' or ''[[Aeromonas hydrophila]]''
-** [[Clindamycin]], for synergy and the Eagle phenomenon and decreased toxin production
+*'''Type 4:''' fungal, caused by ''[[Candida]]'' species, and exceedingly rare
-** +/- [[vancomycin]]
-* Then narrow based on the Gram stain an culture
-* Can consider IVIg, rarely, in [[toxic shock syndrome]]
+==Management==
-=== Eagle Effect ===
+*Surgical debridement!
-* Originally, referred to decreased effectiveness of penicillins at high concentrations
+*Empiric antibiotics
-* Now, refers to decreased effectiveness of penicillins at high bacterial burden (when in stationary phase)
+**[[Piperacillin-tazobactam]]
-* [[Clindamycin]] kills enough of the bacteria that are in stationary phase that the bacteria return to logarithmic growth phase, where penicillins are more effective
+**[[Clindamycin]], for synergy and the Eagle phenomenon and decreased toxin production
+**+/- [[vancomycin]]
+*Then narrow based on the Gram stain an culture
+*Can consider IVIg, rarely, in [[toxic shock syndrome]]
+===Eagle Effect===
-== Further Reading ==
+*Originally, referred to decreased effectiveness of penicillins at high concentrations
-* RCT of IVIG: Madsen MB ''et al''. [https://doi.org/10.1007/s00134-017-4786-0 Immunoglobulin G for patients with necrotising soft tissue infection (INSTINCT): a randomised, blinded, placebo-controlled trial]. ''Intensive Care Med''. 2017;43:1585-93.
+*Now, refers to decreased effectiveness of penicillins at high bacterial burden (when in stationary phase)
+*[[Clindamycin]] kills enough of the bacteria that are in stationary phase that the bacteria return to logarithmic growth phase, where penicillins are more effective
+==Further Reading==
+*RCT of IVIG: Madsen MB ''et al''. [https://doi.org/10.1007/s00134-017-4786-0 Immunoglobulin G for patients with necrotising soft tissue infection (INSTINCT): a randomised, blinded, placebo-controlled trial]. ''Intensive Care Med''. 2017;43:1585-93.
 [[Category:Skin and soft tissue infections]]