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Hematology 2 > Lecture 14 Cerebral Spinal Fluid Analysis > Flashcards

Lecture 14 Cerebral Spinal Fluid Analysis Flashcards

1
Q

What is the volume of cerebral spinal fluid in adults and neonates?

A

Adults 80-150 mL
Neonates 10-60 mL

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2
Q

What is the composition of CSF?

A

Glucose
Lactic acid
Na+, K+
Chloride
White Blood Cells
Proteins
Urea
Ca2+, Mg2+
HCO3
and
Oxygen

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3
Q

What is the function of CSF?

A
  1. Mechanical protection - acts as a fluid shock absorber and protects from pressure change
  2. Chemical Protection - buffers the brain providing constant chemical (ionic) environment necessary for proper neuronal signaling
  3. Circulation - medium for exchange of nutrients and waste products between blood and nervous tissue.
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4
Q

Where is CSF produced?

A

Formed by secretion from the choroid plexus of the 4 cerebral ventricles.

CSF formed in lateral ventricles flow into 3rd ventricle.

More CSF added in 3rd ventricle then flows in 4th ventricle.

4th Ventricle contributes more fluid and CSF flow into subarachnoid space surrounding brain and spinal cord.

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5
Q

What is the blood-CSF barrier?

A

Materials must be able to pass through ependymal cells that cover the choroid plexuses forming the Blood-CSF barrier.

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6
Q

How does circulating CSF get reabsorbed?

A

Circulating CSF reabsorbed into blood through arachnoid granulations.

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7
Q

How much fluid is produced for CSF?

A

20 ml/hr or 480ml/day

Formed and reabsorbed at same rate achieving constant pressure.

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8
Q

For what conditions is CSF tested?

A

CSF can be indicator of several conditions:
- Meningitis, Encephalitis
- Subarachnoid, intracerebral hemorrhage
- Diseases such as Multiple Sclerosis
- Leukemia and Lymphoma with CNS involvement.
- Tumour of brain and spinal cord.

Above conditions are capable of causing fever, paralysis, coma, or even death.

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9
Q

How is CSF collected?

A
  1. A lumbar puncture is performed.
  2. Needle inserted and stylet removed.
  3. CSF pressure measured.
  4. If pressure is normal up to 20mL may be collected. If pressure is abnormal no more than 2.0 mL should be removed.
  5. Three consecutive tubes are drawn (in very sterile tubes):
    Tube 1: Chemistry, Serology, Immunology
    Tube 2: Microbiology
    Tube 3: Hematology
    If 4th tube drawn can be used for Microbiology.
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10
Q

For what general reasons is a lumbar puncture performed?

A
  1. To rule out infection
  2. To detect presence of malignant cells
  3. To instill therapy or anesthetics
  4. To inject contrast media (myelogram)

First to reasons involve the lab.

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11
Q

How many samples/containers of CSF should be collected?

A

At least 3 samples shown be drawn if possible.

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12
Q

What does hematology used the CSF fluid for?

A

Visual inspection,
Total cell count and differential cell count.

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13
Q

What conditions is there high pressure in the CSF (laying down position)?

A

Infection
Inflammation
Subarachnoid hemorrhage
Malignant & benign tumor
Venus sinus thrombosis
Space lesion (abscess, tumor)
Congestive Heart failure
Cerebral edema

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14
Q

What conditions is there low pressure in the CSF (laying down position)?

A

Spinal block
Loss of fluid
repeated aspiration
Dehydration
Circulatory collaspe

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15
Q

What does normal CSF look like in the visual inspection?

A

Clear and colourless.

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16
Q

If CSF is bloody what do you do?

A

Examine all three tubes.
1. If bloody colour decreases from tube #1 to #3 probably a “bloody tap”.
2. If colour is same in all 3 tubes it is indicative of cerebral bleed.

Some dr’s will ask for counts on tube#1 and #3.

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17
Q

What does cloudy CSF indicate? What about if it is smokey or dusky?

A

Cloudy: Most likely due to WBC’s but can be bacteria or fat globules.

Smokey or dusky: May be due to slight RBC contamination.

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18
Q

What is Xanthochromia?

A

Xanthochromia is a very significant finding - referred to as a pink, orange, or yellow discoloration of the CSF.

Indicative of long standing bleed (at least 2 hrs) and results from the breakdown of RBCs.

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19
Q

How does CSF change in colour following a hemorrhage?

A

CSF Fluid
2-12 hours: Pink or orange xanthochromia
12-24 hrs: yellow xanthochromia (disappears slowly over a period of weeks)

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20
Q

What are the microscopic changes (cells) in CSF following a hemorrhage?

A
  1. 2-24 hours red cells, perhaps with crenation, neutrophils, monocytes, and lymphocytes
  2. 12-18 hours monocytes, erythrophagocytosis and lymphocytes
  3. > 48 hours monocytosis with erythrophagocytosis, siderophages and positive Prussian blue stain.
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21
Q

What must be done with bloody or turbid CSF specimens?

A

Must be spun down to detect xanthochromia.

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22
Q

What is another reason for yellow coloration in CSF fluid seen in immature babies and neonates?

A

Bilirubin is able to cross immature blood-brain barrier.

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23
Q

What are causes (conditions) of Xanthochromia?

A
  1. Subarachnoid hemorrhage
  2. Intracerebral hemorrhage
  3. Jaundice
  4. Premature birth
  5. Extremely high protein levels.
  6. Hypercarotenemia
  7. Meningeal melanoma
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24
Q

Within what time frame should a CSF cell count be performed?

A

Cell count is performed with a hemacytometer within 1 hour of collection.

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25
Q

if the count is very high what can be used to dilute the CSF sample?

A

Dacie’s fluid or normal saline which preserves both WBC and RBCs.

26
Q

What would occur if the CSF was diluted with 1% glacial acetic acid?

A

Lyse RBC’s allowing accurate counting of WBCs.

27
Q

What do you have to be careful of when counting CSF?

A

Care must be taken not to mistake RBCs (especially crenated) with lymphocytes.

Cytospun smears are helpful to differentiate.

28
Q

What are normal leukocyte counts for adults and children in CSF?

A

Adults 0 - 5 x 10^6/L
Children’s 0 - 20x10^6/L.

29
Q

Should RBCs be detected in CSF?

A

There should be no RBCs in CSF but when present detection and reporting of RBCs important to deciding whether contamination or in vivo hemorrhage has occurred.

30
Q

What is the importance of the WBC count of CSF?

A

WBC cell count very important indicator of disease.

Very high WBC count associated with bacterial infection (5-20,000) mean of 800.

Moderate high WBC count associated with viral infection (2-2000) mean of 80.

31
Q

How is the CSF Differential prepared?

A

Historically the differential was prepared from centrifuged deposit of fluid, today the cytocentrifuge is used. It provides greater sensitivity and better morphology.

32
Q

What is a normal CSF differential in an adult in terms of % of lymphs, monos and neutrophils?

A

70% lymphs
30% monocytes
2% neutrophils.

If unable to report % due to small numbers, comment on cells seen.

33
Q

What is a normal CSF differential in a neonate in terms of % of lymphs, monos and neutrophils?

A

30% lymphs
70% monocytes
3% neutrophils.

If unable to report % due to small numbers, comment on cells seen.

34
Q

Why is an accurate CSF differential important?

A

CSF Lymphocytosis is associated with different diseases than CSF neutrophilia, than with CSF monocytosis, or CSF Eosinophilia.

35
Q

Why would plasma cells (uncommon in CSF) be seen in CSF?

A

Usually in response to antigenic stimuli if there.

36
Q

Why would basophils be seen in CSF (uncommon)?

A

Response to local immunoallergic response.

37
Q

Besides plasma cells and basophils what other cells are uncommonly seen in CSF?

A
  1. Pia-arachanoid-mesothelial (PAM) (similar in appearance to lymphocyte.
  2. Choroid Plexus cells
  3. Ependymal cells
  4. Cartilage cells
  5. Leukemic, lymphoma, and Tumor cells
38
Q

What is meningitis and encephalitis?

A

Common usage refers to an infectious process of brain and surrounding meninges.

Condition can be grave. Without treatment mortality is high. 60-90% and some infections as high as 100%.

39
Q

Do meningitis and encephalitis require reporting to Public Health?

A

Potential for outbreak necessitates reporting of positives to Public Health and submitting samples for epidemiologic analysis.

Explains the need for timely and accurate diagnosis.

40
Q

What are the two most important CSF chemistry tests and the other two that are sometimes called up for?

A
  1. Two most important tests are for protein and glucose.
  2. Lactate and chloride sometimes called for.

Lactate is an end product of glucose metabolism.

41
Q

What other rare tests can be called for on CSF?

A
  1. Protein Patterns and oligoclonal banding.
    2.Glutamine
  2. CK-BB.
  3. D-Dimer
  4. Tumor Markers.
42
Q

What is the significance of protein in CSF?

A

One of the most sensitive indicators of pathology within the CNS.

43
Q

What are the newborn and adult normal ranges of CSF protein?

A

Newborn: up to 1.5 g/L
Adult: 0.18 to 0.58 g/L reached by 6-12 months of age.

44
Q

What conditions are the greatest increases of CSF protein seen in?

A

Bacterial meningitis (avg. of 418 g/L) and followed by Cerebral hemorrhage (avg. of 270 g/L).

45
Q

How can you test and report protein if sample is bloody?

A
  1. Make correction of 0.01 g/L to be subtracted for every 1000 RBCs. Note: Can only be done if protein and RBC count performed on same tube Or..
  2. Spin sample to remove RBCs (what Harvey’s says he did in his lab practice days).
46
Q

How does glucose enter the CSF?

A

Through diffusion and active transport.

Changes in blood reflected in CSF at least 30 mins later.

47
Q

What is the normal value for glucose in the CSF?

A

Normal value is 60-70% of plasma therefore plasma glucose should always be performed 2-4 hrs prior to CSF measurement.

48
Q

What does increased CSF reflect?

A

Hyperglycemia; no known pathological condition other than diabetes showing increased values.

Result of plasma elevations.

Confirm it means “increased CSF glucose”.

49
Q

What does decreased values of CSF reflect?

A

Decreased values reflect infections, classically bacterial, hypoglycemia.

50
Q

What cells are seen in CSF with a decrease in CSF glucose?

A
  1. Increased WBC and neutrophils –>bacterial meningitis.
  2. Increased WC and lymphocytes –> tubercular or fungal meningitis.
51
Q

What condition is seen with normal glucose but increased lymphocytes?

A

Viral meningitis.

52
Q

Why is lactate measured from CSF? What do high levels suggest?

A

Lactate represents end products of glucose metabolism; high levels suggest bacterial infection and rule out viral.

53
Q

Why is chloride measured in CSF?

A

Useful in diagnosis of tuberculosis meningitis.

54
Q

Why is glutamine measured in CSF?

A

Glutamine is a product of ammonia + alpha-ketoglutarate. In severe liver disease excess of ammonia can cause coma. Also increased in Reye’s syndrome.

55
Q

What can protein patterns in CSF measured by electrophoresis for example indicate?

A

Electrophoresis can be used to measure specific CSF proteins. E.g. increased IgG and numerous oligoclonal bands seen in multiple sclerosis.

56
Q

What can measuring CK-BB detect? Optimal time?

A

Detects brain injury.
Optimum time of detection is 24-72 hours.

Good indicator of prognosis.

57
Q

Why is D-Dimer measured in CSF?

A

Increased in subarachnoid hemorrhage; normal in bloody tap.

58
Q

Why are tumor markers measured in CSF?

A

Can be used to detect and identify tumor cells from the meninges and brain.

59
Q

How can bacterial meningitis be treated?

A

Treated with antibiotics.
T.B. treated with T.B. drugs.

60
Q

How can viral meningitis be treated?

A

Generally not treated (support the patient). Severe cases given anti-viral medications.
Meningoencephalitis from herpes simplex treated with high dose IV acyclovir.

Hematology 2 (23 decks)

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