Lumbar Puncture

Techniques which may help when performing an LP



Diagnostic lumbar puncture is the insertion of a hollow needle into the subarachnoid space of the spinal canal for collection of cerebrospinal fluid (CSF). The procedure may include measurement of CSF pressure; however this measurement is not routine in every Emergency Department.

LP is considered an invasive procedure, and where possible, written consent should be sought from the patient. NSW Health time out should be followed as in all invasive procedures.

Emergency Department indications are clinical suspicion of:
  • CNS infection (meningitis, encephalitis)
  • Subarachnoid Haemorrhage (SAH)


  • Skin infection surrounding the site
  • Evidence of raised intracranial pressure
  • Platelet count less than 50 ×10^9/L
  • INR >1.5
  • Unfractionated Heparin or LMWH in the past 24 hours
  • Known coagulopathy e.g. Haemophila, von Willebrand disease
  • Trauma to lumbar vertebrae
  • Unstable patient/ALOC


  • Failure to obtain CSF
  • Post-lumbar-puncture headache (increased risk with: large bore needle; cutting needle; multiple attempt; excessive CSF removal; dehydration; female patient)
  • Epidural haematoma / local haemorrhage
  • Epidural abscess
  • Transtentorial herniation (view the video 'Lumbar Puncture Procedure and Interpretation' to see a discussion on whether this is the risk we think it is)
  • Back pain

Consent should be documented where possible given it is an invasive procedure. NSW Health time out should be followed as in all invasive procedures.

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