Bacterial meningitis laboratory findings

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Aysha Anwar, M.B.B.S [2]

Overview

Lab findings

Labortary tests which may help identify the bacterial meningitis include non specific tests and specific diagnostic tests.

Non specific tests

Non specific tests include blood tests such as complete blood count, liver function tests, renal function tests, biochemistry, and coagulation profile.^[1]^[2]^[3]

**Laboratory findings**
Test	Findings
Complete blood count	Decreased hemoglobin Decreased hematocrit Elevated CRP
White blood cell count	Elevated or decreased leukocyte count(severe infection) with a left shift^[4]
Biochemistry	Hypoglycemia Elevated creatinine Elevated ALT, AST Possible hyponatremia^[5] Acidosis: High lactate; Low bicarbonate (shock)
Coagulation	Thrombocytopenia-poor prognosis^[4] Increased D-Dimers, Increased PT/APTT-DIC
Blood culture	Positive in 50 to 90 percent of patients ^[1]^[2] Two sets of blood cultures needed before antimicrobials

Specific tests

Specific diagnostic tests include lumbar puncture with CSF examination and CSF culture. CSF examination findings in bacterial meningitis are as follows:


Cerebrospinal fluid level	Normal level	Bacterial meningitis^[6]
Cells/ul	< 5	>300
Cells	Lymphos:Monos 7:3	Gran. > Lymph
Total protein (mg/dl)	45-60	Typically 100-500
Glucose ratio (CSF/plasma)^[7]	> 0.5	< 0.3
Lactate (mmols/l)^[8]	< 2.1	> 2.1
Others	ICP:6-12 (cm H2O)	CSF gram stain, CSF culture, CSF bacterial antigen

References

↑ ^1.0 ^1.1 Geiseler PJ, Nelson KE, Levin S, Reddi KT, Moses VK (1980). "Community-acquired purulent meningitis: a review of 1,316 cases during the antibiotic era, 1954-1976". Rev Infect Dis. 2 (5): 725–45. PMID 6763303.
↑ ^2.0 ^2.1 Talan DA, Hoffman JR, Yoshikawa TT, Overturf GD (1988). "Role of empiric parenteral antibiotics prior to lumbar puncture in suspected bacterial meningitis: state of the art". Rev Infect Dis. 10 (2): 365–76. PMID 3287565.
↑ Kanegaye JT, Soliemanzadeh P, Bradley JS (2001). "Lumbar puncture in pediatric bacterial meningitis: defining the time interval for recovery of cerebrospinal fluid pathogens after parenteral antibiotic pretreatment". Pediatrics. 108 (5): 1169–74. PMID 11694698.
↑ ^4.0 ^4.1 Kaplan SL (1999). "Clinical presentations, diagnosis, and prognostic factors of bacterial meningitis". Infect Dis Clin North Am. 13 (3): 579–94, vi–vii. PMID 10470556.
↑ Brouwer MC, van de Beek D, Heckenberg SG, Spanjaard L, de Gans J (2007). "Hyponatraemia in adults with community-acquired bacterial meningitis". QJM. 100 (1): 37–40. doi:10.1093/qjmed/hcl131. PMID 17178734.
↑ Negrini B, Kelleher KJ, Wald ER (2000). "Cerebrospinal fluid findings in aseptic versus bacterial meningitis". Pediatrics. 105 (2): 316–9. PMID 10654948.
↑ Chow E, Troy SB (2014). "The differential diagnosis of hypoglycorrhachia in adult patients". Am J Med Sci. 348 (3): 186–90. doi:10.1097/MAJ.0000000000000217. PMC 4065645. PMID 24326618.
↑ Leen WG, Willemsen MA, Wevers RA, Verbeek MM (2012). "Cerebrospinal fluid glucose and lactate: age-specific reference values and implications for clinical practice". PLoS One. 7 (8): e42745. doi:10.1371/journal.pone.0042745. PMC 3412827. PMID 22880096.

Template:WikiDoc Sources

[pmid6763303-1] 1.0 ^1.1 Geiseler PJ, Nelson KE, Levin S, Reddi KT, Moses VK (1980). "Community-acquired purulent meningitis: a review of 1,316 cases during the antibiotic era, 1954-1976". Rev Infect Dis. 2 (5): 725–45. PMID 6763303.

[pmid3287565-2] 2.0 ^2.1 Talan DA, Hoffman JR, Yoshikawa TT, Overturf GD (1988). "Role of empiric parenteral antibiotics prior to lumbar puncture in suspected bacterial meningitis: state of the art". Rev Infect Dis. 10 (2): 365–76. PMID 3287565.

[pmid11694698-3] Kanegaye JT, Soliemanzadeh P, Bradley JS (2001). "Lumbar puncture in pediatric bacterial meningitis: defining the time interval for recovery of cerebrospinal fluid pathogens after parenteral antibiotic pretreatment". Pediatrics. 108 (5): 1169–74. PMID 11694698.

[pmid10470556-4] 4.0 ^4.1 Kaplan SL (1999). "Clinical presentations, diagnosis, and prognostic factors of bacterial meningitis". Infect Dis Clin North Am. 13 (3): 579–94, vi–vii. PMID 10470556.

[pmid17178734-5] Brouwer MC, van de Beek D, Heckenberg SG, Spanjaard L, de Gans J (2007). "Hyponatraemia in adults with community-acquired bacterial meningitis". QJM. 100 (1): 37–40. doi:10.1093/qjmed/hcl131. PMID 17178734.

[pmid10654948-6] Negrini B, Kelleher KJ, Wald ER (2000). "Cerebrospinal fluid findings in aseptic versus bacterial meningitis". Pediatrics. 105 (2): 316–9. PMID 10654948.

[pmid24326618-7] Chow E, Troy SB (2014). "The differential diagnosis of hypoglycorrhachia in adult patients". Am J Med Sci. 348 (3): 186–90. doi:10.1097/MAJ.0000000000000217. PMC 4065645. PMID 24326618.

[pmid22880096-8] Leen WG, Willemsen MA, Wevers RA, Verbeek MM (2012). "Cerebrospinal fluid glucose and lactate: age-specific reference values and implications for clinical practice". PLoS One. 7 (8): e42745. doi:10.1371/journal.pone.0042745. PMC 3412827. PMID 22880096.

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