Questions and Answers
Most CSF originates in the _____ _____
choroid plexus
What is the definition of choroid plexus?
A highly vascular portion of the lining of the ventricles that secretes cerebrospinal fluid.
What are the three main functions of cerebrospinal fluid?
The protein level of normal CSF is dramatically _____ than that of plasma.
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In an adult, ____ WBC/µL is considered normal.
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Children will have slightly higher cell counts. Up to __ WBC/µL is within normal limits for newborns.
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Lymphocytes account for ___% of these cells.
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What is the approximate volume of spinal fluid in an adult?
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A CSF sample is obtained by a physician usually via?
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Hematologic analysis of CSF samples should be performed within _____ of fluid aspiration.
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What may indicate the presence of a thin membrane or 'scum' on the surface of the CSF specimen?
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CSF samples from patients who have suffered a subarachnoid hemorrhage (SAH) may have a _____ supernatant when the sample is centrifuged within one hour following collection.
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The term used to describe the colored supernatant is?
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What is xanthochromia the result of?
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_____ could also cause the CSF to be xanthochromic.
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What is the Neubauer counting chamber formula used for?
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What are the CSF counting guidelines?
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When do you count the 4 corner squares for WBCs?
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The nucleated cells seen in normal adult CSF are predominantly?
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What does pleocytosis refer to?
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_____ are indications that an SAH had occurred sometime prior to collection of the CSF sample.
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The formation of hemosiderin deposits and hematoidin crystals occurs approximately __ hours following a subarachnoid hemorrhage.
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The hemosiderin deposits, hematoidin crystals, and siderophages may be present in the CSF for _____.
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Bone marrow contamination of CSF:
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Blast cells may be seen in the spinal fluid when cell proliferation in _____ spreads to the central nervous system.
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Which of the following are characteristics of malignant cells?
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Where does most cerebrospinal fluid (CSF) originate?
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Study Notes
Cerebrospinal Fluid (CSF) Overview
- Most CSF originates in the choroid plexus, a network of blood vessels in the ventricles.
- Choroid plexus plays a crucial role in the secretion of cerebrospinal fluid.
Functions of CSF
- Protects the brain and spinal cord from mechanical trauma.
- Supplies essential nutrients to nervous system tissues.
- Removes metabolic waste products.
Analyte Reference Intervals
- Reference intervals for analytes differ between CSF and plasma; normal CSF protein levels are significantly lower than those in plasma.
Normal Cell Counts in CSF
- In adults, a normal CSF white blood cell (WBC) count is between 0 to 5 WBC/µL.
- Newborns may have counts up to 30 WBC/µL, which is also considered normal.
- Lymphocytes typically account for 60-100% of the nucleated cells present in CSF.
CSF Volume and Collection
- The approximate volume of CSF in an adult is between 90-150 mL.
- CSF samples are commonly obtained via lumbar puncture (usually at L3-4).
Hematologic Analysis Timing
- Hematologic analysis of CSF should be conducted within one hour following aspiration to maintain cell stability, as both RBCs and WBCs can rapidly lyse in the hypotonic CSF.
CSF Characteristics
- Clots may create a thin membrane called pellicle, made of fibrinogen and WBCs.
- CSF from patients with subarachnoid hemorrhage (SAH) can present a pink- to yellow-tinged supernatant after centrifugation.
- This colored supernatant is referred to as xanthochromia, resulting from RBC breakdown products.
Causes of Xanthochromia
- Xanthochromia can also occur due to high serum bilirubin levels.
Counting Cells in CSF
- Use a Neubauer counting chamber for nucleated cell counts in diluted CSF samples.
- For WBC counts, assess four corner squares when diluted cell counts range between 10 and 100.
Nucleated Cells in Adult CSF
- Normal adult CSF contains predominantly lymphocytes and monocyte/macrophages.
Pleocytosis and SAH Indications
- Pleocytosis refers to an increased number of cells in CSF.
- Presence of macrophages (erythrophages) that have ingested RBCs, or hemosiderin-laden cells (siderophages), indicates prior subarachnoid hemorrhage.
Temporal Aspects of Hemorrhage Indicators
- Hemosiderin deposits and hematoidin crystals appear around 18 hours post-SAH, remaining detectable for several months.
Bone Marrow Contamination
- Bone marrow contamination in CSF can show immature myeloid and erythroid cells, which do not reflect the patient's peripheral blood status.
Malignant Cells in CSF
- Acute leukemia or lymphoma may result in the presence of blast cells in the spinal fluid.
- Characteristics of malignant cells include:
- Giant cells and multinucleation.
- Cellular crowding with irregular nuclear shapes.
- High nuclear to cytoplasmic ratio and vacuolation in cytoplasm and nucleus.
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Description
Test your knowledge about cerebrospinal fluid with this quiz. Learn about its origins, functions, and the importance of the choroid plexus in CSF production. Perfect for students studying neuroanatomy and physiology.
