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

2. 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

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

4. Lumbar puncture Equipment Spinal/lumbar puncture tray Sterile dressing
Sterile gloves
Sterile drape
Antiseptic solution with skin swabs
Lidocaine 1% without epinephrine
Syringe, 10 mL
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

5. 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 L2-L3,L3- L4 or L4-L5 intervertebral spaces (L4 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

6. Lumbar puncture Estimating CSF opening pressure
Normal CSF pressure ~10-20 cmH20 (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 H20

7. Lumbar puncture Samples collection Sterile conditions
Specimens should be taken to the lab promptly
4 sterile tubes
Tube 1 – CrAg, 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.

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

9. 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 H20
Manometer should always be used - pressure cannot be assessed by simply observing the speed with which the CSF drips out of the needle

10. END