Necrotizing fasciitis laboratory findings: Difference between revisions
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==Overview== | ==Overview== | ||
Laboratory findings consistent with the diagnosis of necrotizing fasciitis include positive blood and tissue culture, elevated inflammatory markers, [[ | Laboratory findings consistent with the diagnosis of necrotizing fasciitis include positive blood and tissue culture, elevated inflammatory markers, [[leukocytosis]] and elevated [[serum creatinine]]. LRINEC is a diagnostic scoring system used to distinguish necrotizing fasciitis from other [[soft tissue]] infections. | ||
==Laboratory Findings== | ==Laboratory Findings== | ||
| Line 17: | Line 17: | ||
*Enrichment cultures (patients with recent [[antibiotic]] use) | *Enrichment cultures (patients with recent [[antibiotic]] use) | ||
=== | ===Biochemistry=== | ||
The biochemistry findings consistent with diagnosis of necrotizing fasciitis include: | The biochemistry findings consistent with diagnosis of necrotizing fasciitis include: | ||
*Elevated [[C-reactive protein]] | *Elevated [[C-reactive protein]] | ||
| Line 27: | Line 27: | ||
*[[Arterial blood gas]] ([[ABG]]) analysis | *[[Arterial blood gas]] ([[ABG]]) analysis | ||
*Urine analysis | *Urine analysis | ||
*Elevated [[ | *Elevated [[blood urea nitrogen]] ([[BUN]]) | ||
===Hematology=== | ===Hematology=== | ||
The following are complete blood count with differential findings: | The following are complete blood count with differential findings: | ||
:*Rapidly falling [[hemoglobin]] | :*Rapidly falling [[hemoglobin]] | ||
:*[[ | :*[[Leukocytosis]] (>14,000/µL) | ||
:*[[ | :*[[Leukopenia]] (if associated with [[STSS]]) | ||
:*[[Lymphopenia]] | :*[[Lymphopenia]] | ||
:*[[Thrombocytopenia]] | :*[[Thrombocytopenia]] | ||
| Line 39: | Line 39: | ||
===Laboratory risk indicator for necrotizing fasciitis (LRINEC) scoring system=== | ===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.<ref name="pmid15241098">{{cite journal| author=Wong CH, Khin LW, Heng KS, Tan KC, Low CO| title=The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. | journal=Crit Care Med | year= 2004 | volume= 32 | issue= 7 | pages= 1535-41 | pmid=15241098 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15241098 }} </ref> | *LRINEC is a diagnostic scoring system used to distinguish necrotizing fasciitis from other soft tissue infections.<ref name="pmid15241098">{{cite journal| author=Wong CH, Khin LW, Heng KS, Tan KC, Low CO| title=The LRINEC (Laboratory Risk Indicator for Necrotizing Fasciitis) score: a tool for distinguishing necrotizing fasciitis from other soft tissue infections. | journal=Crit Care Med | year= 2004 | volume= 32 | issue= 7 | pages= 1535-41 | pmid=15241098 | doi= | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15241098 }} </ref> | ||
*Risk assessment of necrotizing faciitis using LRINEC score: | *Risk assessment of necrotizing faciitis using LRINEC score: | ||
:*Low risk: ≤5 | :*Low risk: ≤5 | ||
| Line 124: | Line 123: | ||
Other diagnostic studies of necrotizing fasciitis include:<ref name="pmid15332062">{{cite journal| author=Wang TL, Hung CR| title=Role of tissue oxygen saturation monitoring in diagnosing necrotizing fasciitis of the lower limbs. | journal=Ann Emerg Med | year= 2004 | volume= 44 | issue= 3 | pages= 222-8 | pmid=15332062 | doi=10.1016/S0196064404003038 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15332062 }} </ref> | Other diagnostic studies of necrotizing fasciitis include:<ref name="pmid15332062">{{cite journal| author=Wang TL, Hung CR| title=Role of tissue oxygen saturation monitoring in diagnosing necrotizing fasciitis of the lower limbs. | journal=Ann Emerg Med | year= 2004 | volume= 44 | issue= 3 | pages= 222-8 | pmid=15332062 | doi=10.1016/S0196064404003038 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15332062 }} </ref> | ||
*Tissue oxygen saturation monitoring: | *Tissue oxygen saturation monitoring: | ||
:* | :*Occurs at the bedside. | ||
:* | :*Is a noninvasive method to continuously monitor extremities at risk and avoid delayed diagnosis | ||
:*Tissue oxygen saturation is measured using near-infrared [[spectroscopy]]. | :**Tissue oxygen saturation is measured using near-infrared [[spectroscopy]]. | ||
:*In patients with necrotizing faciitis, oxygen saturation are often diminished in the lower extremities and return to normal after [[fasciotomy]]. | :*In patients with necrotizing faciitis, oxygen saturation are often diminished in the lower extremities and return to normal after [[fasciotomy]]. | ||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
Revision as of 20:34, 21 November 2016
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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 consistent with the diagnosis of necrotizing fasciitis include positive blood and tissue culture, elevated inflammatory markers, leukocytosis and elevated serum creatinine. LRINEC is a diagnostic scoring system used to distinguish necrotizing fasciitis from other soft tissue infections.
Laboratory Findings
Laboratory tests consistent with diagnosis of necrotizing fasciitis include:[1]
Microbiology
The following are the tests used to diagnose the causative organism:
- Gram stain and culture of tissues and aspirates
- Blood culture
- Culture of throat and vaginal swabs
- Fungal culture (immunocompromised or trauma patients)
- Enrichment cultures (patients with recent antibiotic use)
Biochemistry
The biochemistry findings consistent with diagnosis of necrotizing fasciitis include:
- Elevated C-reactive protein
- Elevated serum creatine 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 (ABG) analysis
- Urine analysis
- Elevated blood urea nitrogen (BUN)
Hematology
The following are complete blood count with differential findings:
- Rapidly falling hemoglobin
- Leukocytosis (>14,000/µL)
- Leukopenia (if associated with STSS)
- Lymphopenia
- Thrombocytopenia
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]
- 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 |
Tissue oxygen saturation
Other diagnostic studies of necrotizing fasciitis include:[3]
- Tissue oxygen saturation monitoring:
- Occurs at the bedside.
- Is a noninvasive method to continuously monitor extremities at risk and avoid delayed diagnosis
- Tissue oxygen saturation is measured using near-infrared spectroscopy.
- In patients with necrotizing faciitis, oxygen saturation are often diminished in the lower extremities and return to normal after fasciotomy.
References
- ↑ Puvanendran R, Huey JC, Pasupathy S (2009). "Necrotizing fasciitis". Can Fam Physician. 55 (10): 981–7. PMC 2762295. PMID 19826154.
- ↑ 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.
- ↑ Wang TL, Hung CR (2004). "Role of tissue oxygen saturation monitoring in diagnosing necrotizing fasciitis of the lower limbs". Ann Emerg Med. 44 (3): 222–8. doi:10.1016/S0196064404003038. PMID 15332062.