Guidelines for Performing Lumbar Puncture

1. Pre‑procedure Assessment

Absolute contraindications – Do not perform a lumbar puncture in patients with any of the following: a drop in Glasgow Coma Scale > 2 points, focal neurological signs (e.g., unequal or non‑reactive pupils), papilledema, systemic shock or hemodynamic instability, coagulopathy (platelet count < 100 × 10⁹/L or INR ≥ 1.5 unless anticoagulation is reversed), or a local infection at the intended puncture site. 1
Anticoagulation reversal – Prior to puncture, reverse anticoagulants as follows: heparin with protamine; warfarin with vitamin K, prothrombin‑complex concentrate, or fresh‑frozen plasma; and any other coagulation disorder with appropriate replacement therapy. 1
Neuro‑imaging decision – Clinical assessment, not routine head CT, should determine the safety of lumbar puncture. Perform a cranial CT only when clinical features raise suspicion for intracranial hypertension. 1

Atraumatic (pencil‑point) needles – Use 22‑gauge or finer (preferably ≥ 24 g) atraumatic needles (Sprotte or Whitacre) that comply with National Patient Safety Agency standards. These needles reduce post‑procedure complications:
- Post‑lumbar‑puncture headache ↓ from 98/1000 to 39/1000 (‑59 cases per 1000 procedures).
- Need for epidural blood patch ↓ from 24/1000 to 12/1000.
- Auditory disturbances ↓ from 53/1000 to 13/1000.
- Nerve‑root irritation ↓ from 126/1000 to 89/1000.

Lateral decubitus position – Place the patient in the lateral recumbent position for accurate opening‑pressure measurement; the seated position is associated with a higher risk of post‑procedure headache. 3
Insertion technique – Perform rigorous skin antisepsis and local anesthesia. Insert the needle with the bevel parallel to dural fibers (pointing laterally). Keep the stylet in place until the needle tip has entered the subarachnoid space, then remove the stylet before withdrawing the needle to lessen headache incidence.
CSF collection method – Allow CSF to flow passively (no active aspiration) to reduce complications. Do not collect more than 30 mL of CSF in a single procedure. 3

Normal opening pressure – < 200 mm H₂O in the lateral decubitus position. 4
Elevated opening pressure (≥ 250 mm H₂O) – Drain sufficient CSF to lower the pressure by at least 50 % or to < 200 mm H₂O. Collect a minimum of 10 mL to avoid repeat procedures, but never exceed 30 mL. 4

Mandatory tests:
- Cell count with differential.
- Glucose concentration (compared with simultaneous serum glucose).
- Protein concentration.
- Gram stain and culture when infection is suspected.

Skill level over specialty – The technical training of the operator determines adverse‑event risk. Nurses and physicians with comparable training exhibit similar complication rates (odds ratio 0.98; 95 % CI 0.23–4.26; p = 0.98). 3

First‑line – Percutaneous lumbar drainage to achieve a 50 % pressure reduction.
If pressure remains ≥ 250 mm H₂O – Perform daily lumbar punctures initially to maintain normal pressure.
Severe elevation (≥ 400 mm H₂O) or need for frequent taps – Consider placement of a lumbar drain.
Failure of lumbar measures or progressive neurological decline – Proceed to ventriculoperitoneal shunting.
Pharmacologic adjuncts – Corticosteroids, acetazolamide, and mannitol have no demonstrated benefit in cryptococcal meningitis and should not be used. 4

The presence of moderate to severe impairment of consciousness or a fall in GCS of >2 is a contraindication to immediate lumbar puncture, as it may indicate increased intracranial pressure 5, 6
Focal neurological signs, including unequal, dilated or poorly responsive pupils, are a contraindication to immediate lumbar puncture, as they may indicate a space-occupying lesion or other neurological condition 5, 7
Papilloedema, a direct indicator of raised intracranial pressure, is a contraindication to immediate lumbar puncture 5, 7
Systemic shock or clinically unstable patients should not undergo immediate lumbar puncture, as it may worsen their condition 5, 8
Local infection at the lumbar puncture site is a contraindication to immediate lumbar puncture, as it may introduce bacteria into the cerebrospinal fluid 5, 8
Coagulation results outside normal range, including platelet count <100 × 10⁹/L, are a contraindication to immediate lumbar puncture, as they may increase the risk of bleeding 5, 8
Anticoagulant therapy is a contraindication to immediate lumbar puncture, as it may increase the risk of bleeding 5, 8

Clinical assessment, rather than cranial CT, should be the primary determinant of whether it is safe to perform a lumbar puncture in patients with suspected CNS infections 9, 10
If no clinical contraindications are present, immediate lumbar puncture can be performed 9, 10
If clinical contraindications are present, a CT scan should be performed as soon as possible to assess for raised intracranial pressure or other complications 9, 10
If the CT scan shows significant brain shift, tight basal cisterns, or raised ICP, lumbar puncture should be deferred 9, 8
For patients on anticoagulant therapy, reversal with protamine, vitamin K, or fresh frozen plasma may be necessary before lumbar puncture 9, 10

The use of atraumatic needles that meet National Patient Safety Agency standards can help minimize the risk of complications during lumbar puncture 9, 10
Collecting sufficient cerebrospinal fluid (at least 10 ml) can help avoid repeat procedures and ensure accurate diagnosis 9, 10
In patients with HSV encephalitis, repeat lumbar puncture may be valuable if clinical suspicion persists, as approximately 5-10% may have normal initial CSF findings 11
Relying solely on CT to rule out raised intracranial pressure is not recommended, as it may not accurately detect all cases of increased pressure 9, 12