CSF Analysis

What are the three layers of the meninges?

Dura mater, arachnoid mater, pia mater

What are the functions of CSF?

- Supplies nutrients to nerve tissue

- Removes metabolic waste

- Mechanical barrier to cushion the brain and spinal cord against trauma

The choroid plexuses are clusters of ______ hanging from the roof of each ventricle in the brain.

capillaries

The blood brain barrier is a highly selective membrane that only allows what substances through?

Water, glucose, amino acids, CO2, chloride

What kinds of things are found in CSF?

Sodium, chloride, potassium, CO2, calcium, magnesium, lactate, pre-albumin, albumin, ammonia, creatinine, glucose, iron, phosphorus, lipids, urea, globulins

Most CSF is formed by the ventricular ______ cells.

choroid plexus

A minority of CSF is formed by other sites and the ependymal lining of the ______ and ______.

ventricles, subarachnoid space

CSF volume in adults

90-150mL

CSF volume in neonates

10-60mL

CSF is replaced by the body 3-4 times a day to create intracranial ______.

pressure

Choroid plexus cells

Can also be more strung out

The blood brain barrier is composed of the ______ and ______.

choroid plexus, capillary endothelium

Where is a lumbar puncture performed?

Between the 3/4th or 4/5th lumbar vertebrae

(In the spinal subarachnoid space)

Intracranial pressure determines the ______ of CSF that can be safely removed.

amount

When intracranial pressure is normal, no more than ______mL of CSF should be removed.

20mL

What are some diseases that warrant CSF collection?

- Meningeal infection (Meningitis, Encephalitis, Syphilis)

- Hemorrhages

- CNS malignancy

- Leukemias and lymphomas

- MS

______ is a tell-tale sign of meningitis.

Brudzinski's neck sign

What departments do the 4 CSF collection tubes go to?

Tube 1: Chemistry

Tube 2: Microbiology

Tube 3: Hematology

Tube 4: Immunology/Serology (if collected)

Alternate order (to compare cell counts):

Tube 1: Hematology

Tube 2: Chemistry

Tube 3: Microbiology

Tube 4: Hematology

Normal CSF is ______ and ______.

clear, colorless

Cloudy CSF can indicate ...

- Pleocytosis (many WBCs)

- Many RBCs

- Microorganisms

- Increased protein or fat

Xanthochromia indicates the presence of ______ degradation products.

RBC

Pink CSF indicates slight amounts of ______.

oxyhemoglobin

Orange CSF indicates heavy ______.

hemolysis

Yellow CSF indicates the conversion of oxyhemoglobin to ______.

unconjugated bilirubin

What are some other causes of xanthochromia?

- Elevated serum bilirubin

- Carotene

- Increased protein concentrations

- Melanoma

- Premature neonates (immature liver)

Xanthochromia indicative of hemorrhage will have ______ color distribution in all CSF tubes.

even

A traumatic tap will show a ______ in color of CSF between tubes.

gradient (tube 1 is the darkest color)

Hemorrhage will not cause the CSF to ______ within the tube, but traumatic tap will due to the presence of fibrinogen from plasma.

clot

Normal adult protein range in CSF

15-45mg/dL

Normal neonate protein range in CSF

15-100mg/dL

What are the types of protein in the CSF?

- Prealbumin

- Albumin

- Beta-2-microglobulin

- Myelin Basic Protein (MBP)

- C-Reactive Protein (CRP)

Increased MBP in CSF is seen in ______ and is a predictive marker in patients with serious ______ injuries.

MS, head

Increase CRP in CSF indicates ______.

inflammation

Elevated protein levels in CSF can indicate ...

- Damage to BBB

- Decreased clearance of normal protein from fluid

- Meningitis, degeneration of neural tissue

- Hemorrhage, Ig production within CNS

When electrophoresis is performed, ______ will be seen in CSF samples from MS patients.

oligoclonal bands

What substances are assessed from the CSF chemistry tube?

- Glucose

- Enzymes

- Lactate

- CSF/Serum Albumin Index

- IgG Index

Healthy CSF glucose range

45-80mg/dL

(Fasting specimen)

CSF glucose is ______% that of plasma glucose.

60-70%

Increased CSF glucose can be seen with ______ and ______.

hyperglycemia, traumatic taps

Decreased CSF glucose can be seen with ...

- Bacterial meningitis

- Damage to BBB

- TB meningitis

Healthy lactate dehydrogenase CSF range

0-25U/L

(10% of plasma level)

Increased lactate dehydrogenase is associated with ...

- Malignancy

- Bacterial and viral meningitis

- Neonatal CNS hemorrhage

- Epilepsy

- Stroke

CK-BB is released in the brain 6 hours after injury and can be used to estimate the extent of ______.

brain damage

Over 35mg/dL lactate in CSF is caused by ______.

bacterial meningitis

25-35mg/dL lactate in CSF is caused by ______.

tubercular/fungal meningitis

Xanthochromic CSF will have falsely ______ lactate.

elevated

(Lactate and LDH are found in RBCs)

CSF albumin is ______ times lower than serum.

500x

Abnormal albumin in CSF indicates disruption of the ______.

BBB

CSF/Serum Albumin Index Equation

Index = Albumin(CSF)/Albumin(Serum)

A normal CSF/Serum Albumin Index is under ______, which indicates an intact BBB.

9

IgG Index Equation

IgG Index = IgG(CSF)/IgG(Serum)//Albumin Index

Normal IgG Index Range

0.25-0.7

IgG index above 0.7 indicates IgG is produced in the ______ with ______ BBB.

CSF, intact

IgG index below 0.25 indicates IgG crossing from the blood through a ______ BBB.

damaged

The microbiology CSF tube undergoes ______ and ______.

gram stain, culture

(bacterial, fungal; specimen is centrifuged to concentrate)

Premature neonate Acute Meningitis causative bacteria

GNR

Infant Acute Meningitis causative bacteria

L. monocytogenes

S. agalactiae

S. pnuemoniae

H. influenzae

Children Acute Meningitis causative bacteria

N. meningitidis

S. pnuemoniae

H. influenzae

Adolescent Acute Meningitis causative bacteria

N. meningitidis

Adult Acute Meningitis causative bacteria

S. pnuemoniae

Elderly Acute Meningitis causative bacteria

GNR

Chronic Meningitis causative bacteria

M. tuberculosis (and other nontuberculous mycobacteria)

T. pallidum

B. burgdorferi

B. recurrentis

Leptospira

Cryptococcus neoformans India ink stain (CSF)

Shows capsule and budding yeast

Gram stain on Cryptococcus neoformans produces a ______ pattern.

starburst

The hematology CSF tube is used for ...

Cell counts, differentials

Healthy adult cell count range

0-10 mononuclear cells/mm^3

Healthy neonate cell count range

0-30 mononuclear cells/mm^3

In order to perform a CSF cell count, RBCs are lysed using ______.

acetic acid

The WBCs are stained with ______ and counted.

methylene blue

In order to produce a differential CSF count, ______ is used to concentrate the cells.

cytocentrifugation

A ______ additive is added to increase cell yield.

protein (albumin)

Cells are ______, forcing into a monolayer on the slide.

flat/stretched

If possible a differential count on CSF should include the counting and classification of ______ cells.

100

Children have more ______ than adults.

monocytes

Healthy WBC ranges in adults

Lymphocytes: 60%

Monocytes: 30%

Neutrophils: 2%

Healthy WBC ranges in children

Lymphocytes: 20%

Monocytes: 70%

Neutrophils: 4%

Neutrophils (PMNs) are found primarily in ______.

bacterial meningitis

Eosinophils in CSF are observed with ______ and ______ infections.

parasitic, fungal

Eosinophils can also be increased with an improperly placed/malfunctioning ______.

shunt

Macrophages are increased in CSF with ...

- Viral and tubercular meningitis

- Hemorrhage

Hemorrhage will show what two things in/near the macrophages in CSF?

Hemosiderin and hematin

(From phagocytized and degraded RBCs)

nRBCs are increased in CSF with ...

- BM contamination

- Capillary structures in epithelial cells from traumatic taps

Neutrophils with ______ nuclei may resemble nRBC.

pyknotic

What are some abnormal cells seen in CSF with leukemias/lymphomas?

- Blasts (acute leukemia)

- Plasma cells (MM)

- Atypical lymphocytes (possible viral infection)

Tumor cells in CSF

VDRL can be used to diagnose ______, accompanied by a positive confirmatory test.

Neurosyphilis (tertiary)