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| ==Background== | | ==Background== |
| ===Fasciitis===
| | *Abbreviation: NSTI |
| # does not involve muscle- but can spread to muscle
| | *Includes necrotizing forms of cellulitis, myositis, and fasciitis |
| # syst toxicity
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| # skin c blebs, crepitus, necrosis
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| # risks- dm, pvd, trauma or recent surg
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| # pain varies since nerve endings damaged- cessation or absence of pain may indicate worsening sxs
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| # necrosis of fat can lead to soapanification and hypocalemia
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| # pcn/gent/clinda
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| ===Myositis=== | | ===General types=== |
| # myonecrosis- deep soft- tissue infection with death of muscle
| | *Type 1: polymicrobial infection |
| # often with little skin changes but does have gas formation
| | *Type 2: [[group A strep]] |
| # result of trauma or surgical wounds
| | **May occur in healthy individuals |
| # exotoxin of clostridia damages and kills muscle, setting up anaerobic environment that promotes further bacterial growth
| | **May occur via hematogenous spread from throat to site of blunt trauma |
| # odor described as "sickly sweet:
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| # pt usually anuric
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| # muscle appears cooked or dead, does not bleed when cut or retract when pinched
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| ===Necrotizing Fasciitis===
| | {{NSTI types}} |
| # can occur p minor trauma
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| # mortality 20- 50%
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| ==== Microorganisms ==== | | ==Clinical Features== |
| | [[File:NectrotizingFasciitis.jpeg|thumb|Nectrotizing fasciitis]] |
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| #Type I Polymicrobrial- Anaerboic (mixed) staph, proteus, pseudomonas
| | ==Differential Diagnosis== |
| #Type 2 Streptococcal (toxin-generating)
| | {{SSTI DDX}} |
| #Type 3 Clostridium Perfringens (gas gangrene)
| | {{Necrotizing Rashes DDX}} |
| #Grp A beta hemolytic strep pyogenes releases substance in cell wall that causes separation of the dermal connective tissue resulting in continued inflammation and necrosis
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| == Diagnosis == | | ==Evaluation and Management== |
| | See specific type: |
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| "Hard Signs"
| | {{NSTI types}} |
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| #Hypotension
| | ==See Also== |
| #Gas on XR
| | *[[Necrotizing rashes]] |
| #Skin necrosis
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| #Bullae
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| #Crepitance
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| Other common signs/symptoms
| | ==External Links== |
| | *[http://www.mdcalc.com/lrinec-score-for-necrotizing-soft-tissue-infection/ MDCalc - LRINEC Score] |
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| #Systemic toxicity
| | ==References== |
| #Numbness or deep pain out of proportion to exam
| | <references/> |
| #Violaceous or hemorrhagic appearance
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| #Pain beyond margins of cellulitis
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| #Skip lesions
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| Other
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| #Meleney's synergistic gangrene- (progressive bacterial synergistic gangrene) involves superficial and deep fascial planes with thrombosis of subQ vessels and gangrene of tissue
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| #Clostridial cellulitis- healthy muscle not invovled
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| #Fournier's syndrome- necrotizing subq infection of perineum- risk factors include infection or trauma to the perineal area,, anal intercourse, scratches, chemical or thermal burns or diabetes. Obliteration of small branches of pudendal arteries results in dermal gangrene of perineal and scrotal skin.
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| #Necrotizing Otitis Externa ([[Malignant Otitis Externa]]) - deep infection of cartillaginous-bony junction. Risk factors -Elderly, diabetics, immunocomprised. Clinically severe pain and signs of mastoditis. IV antibiotics against pseudomonas, aspergillus, mucorales. ENT consult stat. Complications- Basal skull infection with Cranial Nerves 8, 7, 10(vagus) initially.
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| === Labs ===
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| #Hyponatremia, Na<135
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| #Leukocytosis
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| === Imaging ===
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| #XR- gas
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| #CT- most commonly used, up to 80% sensitive
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| #UTZ- operator dependent
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| #MRI- overly sensitive
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| ==Treatment==
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| # wide surgical debridement and excision
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| # IV ABX
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| # Resuscitate as in sepsis
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| Unclear benefit
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| # hyperbaric O2
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| # IVIG
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| ===Antibiotic Regimens===
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| #Harbor:
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| ## community-acquired- Ceftriaxone/vanc/clinda +/- gent
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| ## hospital-acquired- Zosyn/vanc/clinda
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| ## pcn allergic- Cipro/vanc/clinda/gent
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| #Other common regimens:
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| ## pen/ ox/ gent/ clinda- and also use vanco
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| ==Source== | |
| 6/06 PANI
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| [[Category:ID]] | | [[Category:ID]] |
