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Lumbar puncture: Difference between revisions

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Cerebrospinal fluid can be assessed in the evaluation of many neurological conditions. CSF is mostly obtained by '''lumbar puncture''' (LP). The CSF pressure can also be measured during lumbar puncture.
<section begin="clinical biochemistry" />'''Lumbar puncture''' (LP) is the procedure in which one can obtain and analyse cerebrospinal fluid. Cerebrospinal fluid can be assessed in the evaluation of many neurological conditions. The CSF pressure can also be measured during lumbar puncture.


== Indications ==
== Indications ==
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** [[Pseudotumour cerebri]]
** [[Pseudotumour cerebri]]
* Intrathecal administration of drugs
* Intrathecal administration of drugs
 
<section end="clinical biochemistry" />
== Procedure of lumbar puncture ==
== Procedure of lumbar puncture ==
Performing lumbar puncture while there is increased <abbr>ICP</abbr> can cause [[cerebral herniation]], and so ruling out increased [[ICP]] is important before performing LP. This can be performed by ophthalmoscopy (by looking for papilloedema) or by head [[CT]].
Performing lumbar puncture while there is increased <abbr>ICP</abbr> can cause [[cerebral herniation]], and so ruling out increased [[ICP]] is important before performing LP. This can be performed by ophthalmoscopy (by looking for papilloedema) or by head [[CT]].
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* [[Thrombocytopaenia]] < 40 000
* [[Thrombocytopaenia]] < 40 000
* [[Anticoagulation]] (should be stopped a few days before)
* [[Anticoagulation]] (should be stopped a few days before)
 
<section begin="clinical biochemistry" />
== Normal values of CSF ==
== Interpretation ==
Compared to plasma, the CSF has less protein and very few cells. The electrolyte composition is also different, but this isn't of clinical relevance.
{| class="wikitable"
{| class="wikitable"
!Parameter
!Parameter
!Normal range
!Normal range
![[Bacterial meningitis]]
![[Viral meningitis]]
![[Multiple sclerosis]]
|-
|-
|Pressure
!Pressure
|8 – 20 cmH2O
|8 – 20 cmH2O
|Elevated
|Normal
|Normal
|-
|-
|Appearance
!Appearance
|Like water
|Clear, like water
|Turbid
|Clear
|Clear
|-
|-
|WBCs
!RBCs
|<5 cells/µL
|A few
|Normal
|Normal
|Normal
|-
|-
|Protein
!WBCs
|<0,5 g/L
|< 5 cells/µL
|Elevated (mostly [[granulocytes]])
|Elevated (mostly [[lymphocytes]])
|Elevated (mostly lymphocytes)
|-
|-
|Glucose
!Protein
|>60-70% of blood glucose
|< 0,5 g/L
|Elevated
|Normal
|Normal
|-
!Glucose
|> 60-70% of blood glucose
|Decreased
|Normal
|Normal
|-
!Oligoclonal bands (on electrophoresis)
|Absent
|Absent
|Absent
|Present
|}
|}
Microbiological examinations (culture, PCR), immunoglobulins, as well as measurement of certain biomarkers, like those of dementia or prion disease, can also be measured in CSF.
Microbiological examinations (culture, PCR), immunoglobulins, as well as measurement of certain biomarkers, like those of dementia or prion disease, can also be measured in CSF.
 
<section end="clinical biochemistry" />
== Complications ==
== Complications ==


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* Infection
* Infection


<noinclude>‎[[Category:Neurology]]</noinclude>
<noinclude>‎[[Category:Neurology]]
</noinclude>