Lumbar puncture Dr Neil Stone Centre for Global

Lumbar puncture Dr. Neil Stone Centre for Global Health, Institute of Infection and Immunity St. George’s, University of London

Intended learning outcomes To be aware of the indications and contra-indications for lumbar puncture To be aware of the equipment required for performing a lumbar puncture To understand how cerebrospinal fluid pressures are measured To be aware of the possible complications lumbar puncture

Lumbar puncture Indications Contra-indications • Diagnostic • Infected skin over the needle entry site • CSF sample for Cr. Ag, culture, protein, glucose, cell count • Therapeutic • To reduce intracranial hypertension in cryptococcal meningitis • Suspected cerebral space occupying lesions • Brain abscess • Coagulopathy

Lumbar puncture Equipment • Sterile dressing • Sterile gloves • Sterile drape • Antiseptic solution with skin swabs • Lidocaine 1% without epinephrine • Syringe, 10 m. L • Needles, 20 and 25 gauge • Spinal needles, 20 and 22 gauge • Manometer with three-way stopcock • Four plastic test tubes, numbered 1 -4, with caps Spinal/lumbar puncture tray

Lumbar puncture Procedure • Explain the procedure to the patient or attendant and get informed consent. • Asepsis should be observed during the procedure. • Use local anaesthetic agents to anaesthetise the skin. • Access the subarachnoid space through L 2 -L 3, L 3 L 4 or L 4 -L 5 intervertebral spaces (L 4 can be located between the iliac crests) • Perform manometry. • Collect at least 10 drops of CSF in each of the 4 test tubes. • Apply sterile dressing at the site of the puncture • Place patient in supine position. • Draw serum glucose to compare CSF glucose

Lumbar puncture Estimating CSF opening pressure • Normal CSF pressure ~10 -20 cm. H 20 (recumbent) • Patient must be in lateral recumbent position. • After CSF is returned from the needle, attach the manometer through the stopcock. • Note the height of the fluid when it stops rising. • Keep the patients leg straight to avoid getting false elevated CSF pressure. • Recheck the pressure at the end of the procedure (closing pressure) – aim for <20 cm H 20

Lumbar puncture Samples collection • Sterile conditions • Specimens should be taken to the lab promptly • 4 sterile tubes • • Tube 1 – Cr. Ag, protein and glucose levels Tube 2 –India ink, Gram stain, C&S Tube 3 - Cell count and differential Tube 4 – “Special” or repeat tests CSF collection tubes. Image courtesy of Gil Z Shlamovitz, MD.

Lumbar puncture Possible complications Post-spinal headache • Post–spinal puncture headache (20 -70%) • Leakage of CSF from puncture site. • Bloody tap • Onset is usually 24 -48 hours post- • Dry tap procedure • Infection • Self-limiting (<7 days). • Haemorrhage • Improves in the supine position • Dysesthesia • Treat with simple analgesics and caffeine. • Post–dural puncture cerebral herniation

Recommendations • Improve access to lumbar puncture equipment including manometers • Provide adequate training in the technique to health care workers • Perform therapeutic lumbar punctures as often as needed during CM therapy aiming to keep pressure below 20 cm H 20 • Manometer should always be used - pressure cannot be assessed by simply observing the speed with which the CSF drips out of the needle

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