A lumbar puncture is a procedure where a needle is inserted into the lumbar subarachnoid space to collect cerebrospinal fluid the clear fluid surrounding the brain and spinal cord. CSF analysis reveals infections, bleeding, inflammation, and pressure abnormalities that blood tests and imaging can’t detect. Primarily a diagnostic tool. Occasionally, therapeutic draining of CSF to reduce pressure in NPH or idiopathic intracranial hypertension.
According to Dr. Gurneet Singh Sawhney, a neurosurgeon in mumbai, “A lumbar puncture is one of the most informative investigations in neurology. A CT scan tells you about structure; an LP tells you about what’s happening in the fluid that surrounds it, and sometimes the diagnosis is only in the fluid.”
Severe headache, suspected meningitis, unexplained neurological symptoms requiring CSF analysis?
When Is a Lumbar Puncture Indicated?
LP is contraindicated when raised ICP is present without imaging to confirm the cause; herniation risk from a sudden pressure gradient change is real. Brain imaging comes before LP in any presentation where raised ICP is possible. This safety check follows Mumbai evaluations for brain surgery and uses the same pre-procedural assessment used in Mumbai evaluations.
What Does a Lumbar Puncture Involve and What Can Go Wrong?
For the clinical context where LP is most urgently needed to separate a catastrophic diagnosis from a benign one, see thunderclap headache.
What Does CSF Analysis Actually Show?
The normal pressure hydrocephalus tap test is one specific application of this broader CSF assessment capability.
Frequently Asked Questions
Is a lumbar puncture painful?
Local anaesthetic is used. Most patients feel pressure rather than pain during insertion. Post-procedural headache is the more common issue.
Can a lumbar puncture be done if CT shows raised intracranial pressure?
No LP in the presence of raised ICP carries herniation risk. Brain imaging is mandatory first to confirm it’s safe to proceed.
How long does a lumbar puncture take?
The procedure itself takes ten to twenty minutes. Post-procedural observation varies by clinical context.
What is xanthochromia and why does it matter?
Yellow discolouration of CSF from haemoglobin breakdown products. Confirms subarachnoid haemorrhage when CT is negative but symptoms are typical.
References
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