The document is a detailed presentation on meningitis, outlining its causes, types, and diagnostic methods, particularly focused on cerebrospinal fluid (CSF) analysis. It includes information on sample collection, normal CSF findings, and specific tests for distinguishing between bacterial, viral, and tubercular meningitis. Key indicators such as glucose levels, protein content, and various enzymes are discussed to aid diagnosis and assessment of severity.

1. MENINGITIS
Group F, Dept. of Biochemistry
Resource faculty: Raju Kumar Dubey
Presenter: - Mr. Shiv K. Chaudhary

2. Group members
• Mr. Surendra Mahato
• Mr. Umesh Shah
• Mrs. Shivani Bhandhari
• Mr. Anish Sah
• Mr. Suman Pudasaini
• Mr. Rajkumar Shrestha
• Mr. Shiv K. Chaudhary
• Mr. Raju Kumar Sah
• Mrs. Pabitra Thapaliya
• Mr. Nagendra Shris

3. Introduction
• Infectious disease involving mainly the
inflammation of leptomeninges (aracnoid-
piamater)
• If infection spread to brain parenchyma it is
meningoencephalitis
• It may be caused by bacteria, virus, fungi,
parasites

4. • It is characterised by
– Pyrexia
– Headache
– Meningism
– Photophobia
– Kernig’s sign
– Brudunski’s sign

5. Etiological Classification
 Bacterial or pyogenic
 Viral
 Tubercular
 Fungal
 Syphilitic

6. Sample collection
• Sample: Mainly CSF
– CSF is collected by lumbar puncture between L3-
L4 or L4-L5 vertebrae in three tubes
– Tube1- goes to chemistry for Biochemical analysis
(glucose and protein)
– Tube2 – goes for microbiological testing
– Tube3 goes for haematological analysis

9. Normal CSF findings
ANALYTE CONVENTIONAL UNIT
PROTEINS 15-45 mg/dl
– Prealbumin 2-7%
– Albumin 56-76%
– Alpha 1 globulin 2-7%
– Alpha 2 globulin 4-12%
– Beta globulin 8-18%
– Gamma globulin 3-12%
ELECTROLYTES
– Osmolality 280-300 mOsm/L
– Sodium 135-150 mEq/L
– Potassium 2.6-3 mEq/L
– Chloride 115-130 mEq/L
– Carbon dioxide 20-25 mEq/L
– Calcium 2-2.8 mEq/L
– Magnesium 2.4-3 mEq/L
– Lactate 10-22 mg/dL

10. pH
– Lumbar fluid 7.28-7.32
– Cisternal fluid 7.32-7.34
pCO2
– Lumbar fluid 44-50 mm of water
– Cisternal fluid 40-46 mm of water
pO2 40-44 mm of water
Other constituents
– Ammonia 10-35 ug/dL
– Glutamine 5-20 mg/dL
– Creatinine 0.6-1.2 mg/dL
– Glucose 50-80 mg/dL
– Iron 1-2 ug/dL
– Phosphorus 1.2-2 mg/dL
– Total lipid 1-2 mg/dL
– Urea 6-16 mg/dL
– Urate 0.5-3 mg/dL
– Zinc 2-6 ug/dL

11. Estimation of Glucose
 Done by any usual blood glucose method (GOD-
POD)
 Normal value: 50-80 mg /dL
 Normal CSF/plasma glucose ratio varies from 0.3-0.9
 Decrease in CSF glucose is the most pathological
change seen in:
 In bacterial meningitis: 0-15 mg/dl
 In tuberculous meningitis: 15-20 mg/dl
 In viral meningitis: often normal
 Causes of the decrease in CSF glucose is due to:
 Increased anaerobic glycolysis by the leucocytes and
bacteria
 Decrease permeability in chronic cases

12. ESTIMATION OF CSF PROTEINS
• Determination of CSF proteins is usually done by
Turbidimetric methods or occassionaly by colorimetric
methods
• In Turbidimetric method:
– Reagent: 3% Sulphosalicyclic acid (SSA) or Trichloro acetic
acid (TCA)
Procedure :
• 1 ml of the CSF is mixed with 3 ml of SSA/TCA
– mix and allow to stand for 5 minutes
• The turbidity developed is compared with the tubes of std
• Normal value: 15-45 mg/dl

13. • Albumin and IgG measurement:
Normal CSF/Serum albumin = CSF albumin (mg/dL)
Serum albumin (mg/dL)
– The normal ratio is 1:230
– In meningitis the ratio increases
CSF/serum IgG ratio = CSF IgG (mg/dL)
Serum IgG (mg/dl)
– The normal ratio is 1:390
– In meningitis this ratio increases

14. CSF IgG index = CSF IgG (mg/dL) x serum albumin(g/dL)
serum IgG(g/dL) x CSF albumin(mg/dL)
The reference range for the index is 0.25 to 0.80
The index is elevated when there is increased CNS IgG
production such as in MS
The IgG index is decreased when the integrity of the BBB
is compromised, as in meningitis and tumors

15. Causes of the increase in the protein level
• Either due to Increased permeability of blood CSF barrier and brain CSF
barrier
• Or, Increase in intrathecal immunoglobulins synthesis
 Other CSF proteins:
 Alpha 2 macroglobulins
– significant elevation occurs in bacterial meningitis. So it helps in the rapid
differentiation between bacterial and aseptic meningitis
 C reactive protein (CRP)
 CSF CRP is useful in differentiating the viral meningitis from bacterial
meningitis
 CSF CRP is is more useful screening test for viral vs. bacterial meningitis in
children
 It is increased in bacterial meningitis; more in gram negative than in gram
positive
 Fibronectin
– elevation reported in bacterial meningitis while decreased level is observed
in viral meningitis

16. • Electrophoresis of CSF protein:
– It shows the presence of many different globulins
– When done in cellulose acetate/ or agar gel the
proteins are separated into different fractions
– When expressed as % of total proteins of CSF the
typical findings are

17. Prealbumin 2-7%
Albumin 56-76%
Alpha 1 globulin 2-7%
Alpha 2 globulin 4-12%
Beta globulin 8-18%
Gamma globulin 3-12%

18. • Electrophoretic patterns of CSF show
oligoclonal bands, in the globulin zone
representing antibodies directed against a
variety of antigenic targets

19. Lactate estimation
Normal range= 10-22 mg/dL
• Lactate measurement have been used as the
adjunctive test for differentiating viral from
bacterial meningitis
• In patients with the viral meningitis lactate level is
usually below the 25 mg/dL whereas in bacterial
meningitis its level is above 35 mg/dL
• The sensitivity and specificity are 80 and 90 %
respectively

20. Enzymes
• Adenosine deaminase (ADA):
– Its measurement has been recommended in tuberculous
meningitis
– ADA level >15 U/L is found to be a strong indication of
tuberculous meningitis
– In non tuberculous meningitis < 15U/L
• Creatine kinase (CK):
– Present in high concentration in brain tissues.
– Increase in CK has been observed in meningitis
– A dividing line of 30 U/L has been suggested
• >30 is suggested for tubercular meningitis and
• <30 pyogenic meningitis

21. • Lactate dehydrogenase:
– the sensitivity and specificity 70-85% depending
on the cutoff value. As with lactate LD activity is
also significantly higher in bacterial meningitis
than in aseptic meningitis.
• CSF lysozyme activity is significantly increased
in patients with both bacterial and
tuberculous meningitis.

22. Summary
Features Normal Bacterial Viral Tubercular Fungal
Macrosc
opic
appeara
nce
Clear,
colorless.
Viscosity
similar to
water.
Cloudy and
frankly
purulent.
Cloudy or
slightly
turbid
Clear or slightly
turbid. Forms fibrin
coagulum on
standing(honey comb
appearance)
-----
Opening
pressure
90-180
mm of
water
Elevated.
>180 mm of
water
Elevated.
>250 mm of
water
Elevated.
>300 mm of water.
Variable
Cell
count
0-4
lymphocy
tes/uL
10-10000
neutrophils
/ul
10-100
lymphocytes
/ul
100-1000
lymphocytes /ul
Variable. Mainly
lymphocytes
Proteins 15-45
mg/dL
Markedly
raised.
1-10g/L
Elevated.
45-100
mg/dL
Raised.
30-400 mg/dL
Increased
Glucose 50-80
mg/dl
0-15 mg/dl
or absent
Normal.
Approx. to
50-
80mg/dl3
Decreased. 15-20
mg/dl
Decreased
Lactic
acid
Normal Mild
marked
increased
Normal mild
increase
Mild moderate
increase
Mild moderate
increase.

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