Necrotizing fasciitis laboratory findings: Difference between revisions
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===Microbiology=== | ===Microbiology=== | ||
The following are the tests used to diagnose the causative organism: | The following are the tests used to diagnose the causative organism: | ||
*Gram stain and culture of tissues and aspirates | *Gram stain and culture of tissues and aspirates (specimens are taken from the margins of involvement for good yield) | ||
*Blood culture | *Blood culture | ||
*Culture of throat and vaginal swabs | *Culture of throat and vaginal swabs | ||
Line 16: | Line 16: | ||
*Enrichment cultures (patients with recent antibiotic use) | *Enrichment cultures (patients with recent antibiotic use) | ||
===Forzen section biopsy=== | |||
The histologic criteria for diagnosis of nectorizing fasciitis include:<ref name="pmid6727947">{{cite journal| author=Stamenkovic I, Lew PD| title=Early recognition of potentially fatal necrotizing fasciitis. The use of frozen-section biopsy. | journal=N Engl J Med | year= 1984 | volume= 310 | issue= 26 | pages= 1689-93 | pmid=6727947 | doi=10.1056/NEJM198406283102601 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=6727947 }} </ref> | |||
*Necrosis of superficial fascia | |||
*Fibrinous thrombi of arteries and veins | |||
*Polymorphonuclear infiltration of the dermis and fascia | |||
*Angitis with fibrinoid necrosis of arterial and venous walls | |||
*Abscence of muscle | |||
*Presence of microorganisms within the destroyed fascia and dermis | |||
===Hematology=== | ===Hematology=== | ||
The following are complete blood count with differential findings: | The following are complete blood count with differential findings: |
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Yamuna Kondapally, M.B.B.S[2]
Overview
Laboratory Findings
Laboratory tests consistent with diagnosis of necrotizing fasciitis include:
Microbiology
The following are the tests used to diagnose the causative organism:
- Gram stain and culture of tissues and aspirates (specimens are taken from the margins of involvement for good yield)
- Blood culture
- Culture of throat and vaginal swabs
- Fungal culture (immunocompromised or trauma patients)
- Enrichment cultures (patients with recent antibiotic use)
Forzen section biopsy
The histologic criteria for diagnosis of nectorizing fasciitis include:[1]
- Necrosis of superficial fascia
- Fibrinous thrombi of arteries and veins
- Polymorphonuclear infiltration of the dermis and fascia
- Angitis with fibrinoid necrosis of arterial and venous walls
- Abscence of muscle
- Presence of microorganisms within the destroyed fascia and dermis
Hematology
The following are complete blood count with differential findings:
- Rapidly falling heamoglobin
- Leucocytosis (>14,000/µL)
- Leucopenia (if associated with STSS)
- Lymphopenia
- Thrombocytopenia
Boichemistry
The biochemistry findings consistent with diagnosis of necrotizing fasciitis include:
- Elevated C-reactive protein
- Elevated serum creatinine kinase
- Hypocalcemia (sign of severity in synergistic NF)
- Hypoalbuminemia
- Hyponatremia (<135mmol/L)
- Elevated serum lactate levels (high serum lactate combined with low sodium levels may be predictive of mortality)
- Arterial blood gas analysis
- Urine analysis
- Elevated Blood urea nitrogen (BUN)
Biopsy
- Deep incisional biopsy (include advancing edge and central necrotic areas)
Laboratory risk indicator for necrotizing fasciitis (LRINEC) scoring system
- LRINEC is a diagnostic scoring system used to distinguish necrotizing fasciitis from other soft tissue infections.[2]
- It was first established by Wong et al in 2004.
- Risk assessment of necrotizing faciitis using LRINEC score:
- Low risk: ≤5
- Intermediate risk: 6-7
- High risk: ≥8
Variable | Score |
---|---|
C- reactive protein (mg/dL)
<150 |
0 |
Total white blood cell count (/mm3)
<15 |
0 |
Hemoglobin (g/dL)
<13.5 |
0 |
Sodium (mmol/L)
≥135 |
0 |
Creatinine (μmol/L)
<141 |
0 |
Glucose (mmol/L)
<10 |
0 |
References
- ↑ Stamenkovic I, Lew PD (1984). "Early recognition of potentially fatal necrotizing fasciitis. The use of frozen-section biopsy". N Engl J Med. 310 (26): 1689–93. doi:10.1056/NEJM198406283102601. PMID 6727947.
- ↑ Wong CH, Khin LW, Heng KS, Tan KC, Low CO (2004). "The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections". Crit Care Med. 32 (7): 1535–41. PMID 15241098.