Contraindications for Lumbar Puncture
Lumbar puncture is contraindicated in patients with increased intracranial pressure due to space-occupying lesions, local skin infection at the puncture site, coagulopathy, and hemodynamic instability, as these conditions significantly increase the risk of serious complications including cerebral herniation and hemorrhage 1.
Absolute Contraindications
Increased Intracranial Pressure with Mass Effect
- Evidence of space-occupying lesions causing brain shift
- Signs requiring cranial imaging before LP:
- Focal neurologic deficits (excluding cranial nerve palsies)
- New-onset seizures
- Severely altered mental status (Glasgow Coma Scale score <10)
- Severely immunocompromised state
- Papilledema (direct indicator of raised intracranial pressure) 1
Infection
- Local skin infection at the puncture site 1
- Cellulitis or abscess over the lumbar region
Coagulation Abnormalities
- Uncorrected coagulopathy
- Platelet count <100 × 10⁹/L (standard recommendation)
- INR >1.4
- Prolonged activated partial thromboplastin time (APTT) >39 seconds
- Rapidly falling platelet count 1, 2
Hemodynamic Instability
- Need for hemodynamic stabilization before diagnostic procedures 1
- Severe cardiorespiratory compromise 2
Other Absolute Contraindications
- Clinical suspicion of spinal cord compression 1
- Suspected spinal epidural abscess
Relative Contraindications
Anticoagulation Therapy
- For patients on heparin: adequate reversal with protamine is required before LP
- For patients on warfarin: reversal with vitamin K, prothrombin complex concentrate, or fresh frozen plasma is mandatory 1, 2
- For patients on aspirin monotherapy: can generally proceed with LP when benefit-risk ratio is favorable 2
- P2Y12 inhibitors (clopidogrel, prasugrel, ticagrelor) should be discontinued 5-7 days before the procedure 2
Thrombocytopenia
- Platelet counts between 20-100 × 10⁹/L require risk-benefit assessment
- Consider platelet transfusion for counts <50 × 10⁹/L 1, 3
Important Clinical Considerations
Imaging Before Lumbar Puncture
- Clinical assessment, not cranial CT, should be the primary determinant of LP safety 2
- If clinical contraindications exist, perform CT scan first, then consider LP on case-by-case basis if no radiological contraindications are identified 1
- CT scan may lead to substantial delay in antibiotic treatment in suspected meningitis, which is associated with poor outcomes 1
Procedural Recommendations
- If LP is delayed due to contraindications, the situation should be reviewed every 24 hours 1
- For suspected bacterial meningitis, if LP is delayed, empiric antibiotic treatment should be started immediately after blood cultures are drawn 1
- Lumbar punctures should be performed with needles that meet the standards set by the National Patient Safety Agency 1
- Single-puncture technique is preferable to reduce bleeding risk 2
Pitfalls and Caveats
Delayed Diagnosis: Deferring LP due to contraindications without starting empiric treatment can lead to increased mortality in bacterial meningitis 1
Unnecessary Imaging: Routine CT scanning before LP in all patients without clinical indications leads to treatment delays without providing useful information 1
Antiplatelet Therapy: Low-dose aspirin alone carries a very low risk of bleeding complications and generally does not need to be discontinued, unlike other antiplatelet agents 2, 3
False Reassurance from Normal CT: A normal CT scan does not completely eliminate the risk of herniation, as deterioration after LP has been reported in patients with bacterial meningitis despite normal imaging 1
Traumatic Taps: Higher risk of traumatic lumbar puncture in patients with elevated INR (>1.5) or prolonged APTT (>40 seconds) 3