CSF examination :

يارب اجعل العمل خالصا لوجهك، نوجه إلى أنه يوجد بوست آخر جامع أكثر من هذا للأطباء العاملين بمجال التحاليل

What's CSF :

Cerebrospinal fluid (CSF) is a clear, watery fluid that surrounds the brain and the spinal cord.

CSF production, circulation, and clearance :

The CSF is produced by the choroid plexus

The fluid will move from the lateral ventricle to ➡ the third and then to the ➡ fourth ventricle, then the fluid moves out into ➡ the subarachnoid space and/or the central canal of the spinal cord.

Finally, ➡ CSF gets drained into the superior sagittal venous sinus through the arachnoid villi.

Around 500 ml is produced each day, with around 150 _ 250 ml being present in the body at any one time.

Function of CSF :

1_ Buoyancy

2_ protectin

3_ Homeostasis

4_ clearing waste

5_ Nutrition.

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When required :

امتى بيطلب التحليل

_ Altered sensorium

_ Coma

_ Unconscious patient

_ Suspected meningitis

_ trauma to the brain or spinal cord

_ Mood swings, depression, confusion, hallucinations, or seizures

_ Infants may be increasingly irritable, cry when they are held, have body stiffness, refuse food,...

فوائد التحليل

CSF testing may reveal more directly the cause of CNS conditions.

The following are some examples:

1_ Meningitis and encephalitis

2_ Autoimmune diseases such as Guillain-Barré syndrome or multiple sclerosis

3_ Cancers of the CNS or cancers that have spread to the CNS, such as leukemia

4_ Alzheimer's disease, an irreversible form of dementia.

5_ bleeding around the brain.

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Test Preparation :

You will be instructed to empty your bladder and bowels before sample collection. It will be necessary to lie still in a curled-up fetal position during the collection and to lie flat and still for some time after the collection.

سيُطلب منك تفريغ المثانة والأمعاء قبل جمع العينة. وسيكون من الضروري الاستلقاء في وضع الجنين الملتوي أثناء التجميع والاستلقاء بشكل مسطح وثابت لفترة زمنية بعد التجميع.

May sitting position.

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Collection of CSF :

في الغالب

Lumbar puncture needle is inserted between the 3rd and 4th lumbar vertebrae, within 2% procaine.

The pressure should be measured by manometer then 3-4 ml are allowed to drip into sterile plain tubes

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Collection and stability :

نجمع 12 مل في 4 عينات

1_ Biochemistry➡ glucose, protein,...

2_ Hematology ( cell count)

3_ Microbiology➡ Gram stain, culture & sensitivity

4_ cytology, Serology or PCR,... etc

Sample stability :

RBCs and WBCs have limited stability so #timing is critical for WBCs to diagnose meningitis or leukemic involvement

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Gross examination :

1_ Appearance and color :

Normal ➡ clear, watery, colorless liquid

Any color is abnormal

_ Reddish ➡

traumatic tap

الأنبوبة الأولي حمراء ويقل تدريجيا في الأنابيب التالية.

intracranial bleeding

كل الأنابيب حمراء

_ Yellow color (xanthochromia) ➡

Previous hemorrhage

نتيجة تكسير كرات الدم الحمراء وظهور البيلوربين

Grossly increased protein

_ Green CSF ➡ may also sometimes be seen with bilirubin or infection.

2_ Turbidity :

Normal is clear

Turbidity may be Infection of CSF / meningitis

3_ Fibrin clot :

Webbed fibrin clot in TB

traumatic fibrin clot

4_ Specific gravity :

Normal 1. 006 _1. 008

5_ pressure :

Normal ➡ 50_175 mm H2O

_ Increased CSF pressure ➡ obstruct the flow of CSF, such as tumors, infection, (hydrocephalus)

_ Decreased pressure ➡ dehydration, shock, leakage,...

Viscosity :

Normal CSF is watery

CSF that is thicker may be seen in people with certain types of cancers or meningitis.

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Chemical examination :

1 _ CSF glucose :

Done as serum by glucose oxidase method

CSF glucose (fasting state) ➡ 40_80 mg/dl

Decreased in glucose indicate Meningitis

Very low glucose seen in bacterial meningitis

Slightly low glucose seen in viral and TB meningitis

Dr

17:04

2_ CSF protein :

Normal level 15_45 mg/dl

Can't be detected by biurets method, it can be detected by :

the dye-binding method as pyrogallol red / coomassie brilliant blue

Increased CSF protein occurs in :

Infection ( meningitis)

CSF obstruction by tumor trauma, inflammation

Guillain Barre syndrome, multiple sclerosis ➡ ⬆ IgG

About 95% of cases of multiple sclerosis patients have positive findings of increased CSF / serum Ig concentration ratio and #oligoclonal band on electrophoretic separation of CSF.

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Hematology examination :

Do cell count of the CSF by cell counter (hemacytometer)

If cells are increased make a smear and see the nature of the cell present

علشان نعمل

Differential WBCs count

Normal CSF cytology :

1_ RBCs ➡ absent

2_ WBCs ➡ 0_5 /μL

Newborn up to 30/μL

Type of WBCs ➡ lymphocyte

60_80% ➡ lymphocyte

30%. ➡ Monocyte

2%. ➡ Others

RBCs

If present you should tell us if it's crenated or not as crenated RBCs may be seen in subarachnoid hemorrhage

Traumatic tap has normal RBCs

WBCs :

Increased cell: infection

Neutrophils ➡ bacterial meningitis

Lymphocyte ➡ viral, TB, fungal, syphilitic, or aseptic meningitis

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