What are the indications for lumbar puncture in neonates (≤28 days old)?

Indications for Lumbar Puncture in Neonates

Lumbar puncture in neonates (≤28 days old) should be performed when there is clinical suspicion of meningitis or sepsis with concerning features, but can be safely deferred in asymptomatic neonates with only obstetric risk factors or isolated early respiratory distress in the first 72 hours of life.

Primary Clinical Indications

Perform lumbar puncture immediately in neonates with:

• Signs of severe sepsis including lethargy, hypothermia, hypotonia, poor perfusion, or apnea 1
• Specific neurological signs such as seizures, abnormal posturing, or bulging fontanelle 1, 2, 3
• Intractable vomiting or unexplained fever with concerning clinical features 2
• Clinical deterioration during observation or treatment 1
• Suspected late-onset sepsis (beyond 72 hours of life), as Gram-negative bacilli or fungi in CSF will significantly affect treatment choices 4

When Lumbar Puncture Can Be Safely Deferred

Delay lumbar puncture and perform only if blood cultures are positive in:

• Asymptomatic neonates with only obstetric risk factors for sepsis in the first 72 hours of life 1, 4
• Early-onset respiratory distress alone without other concerning features in the first 72 hours 4

This approach is justified because meningitis is exceedingly rare within the first 72 hours of life, with studies showing zero cases among hundreds of lumbar punctures performed in this timeframe 1. A prospective policy shift demonstrated that performing three times fewer procedures in neonates <72 hours resulted in no diagnosed or missed cases of meningitis 1.

Absolute Contraindications

Do not perform lumbar puncture if any of the following are present:

• Hemodynamic instability or systemic shock requiring stabilization first 5, 6, 7
• Coagulation abnormalities including platelet count <100 × 10⁹/L or abnormal coagulation results 5, 6, 7
• Local skin infection at the lumbar puncture site 5, 6, 7
• Respiratory insufficiency requiring immediate intervention 5
• Suspected meningococcal septicemia with extensive or spreading purpura 5

Critical Neonatal-Specific Considerations

Important differences in neonatal assessment:

• The ESCMID guideline explicitly states that no data are available to guide daily practice on the use of ancillary investigations before lumbar puncture in neonates 5
• Clinical signs of meningitis differ in neonates: nuchal rigidity is often absent, replaced by axial hypotonia, abnormal behavior, or bulging fontanelle 3
• Resistance from spinal ligaments and dura mater are often absent in young children, requiring different technical approach 3

Clinical Algorithm for Decision-Making

Step 1: Assess age and timing of presentation

• If <72 hours old AND asymptomatic with only risk factors → defer LP, obtain blood cultures 1, 4
• If <72 hours old with early respiratory distress alone → defer LP initially 4
• If any age with concerning clinical features → proceed to Step 2 1

Step 2: Evaluate for signs of severe sepsis or neurological involvement

• If present (lethargy, hypotonia, seizures, poor perfusion, apnea) → proceed to Step 3 1, 2
• If absent and low-risk criteria met → may defer LP 8

Step 3: Check for contraindications

• If hemodynamically unstable, coagulopathic, or local infection → stabilize first, do not perform LP 5, 6
• If no contraindications → perform LP immediately 6

Step 4: If LP deferred, monitor closely and perform if:

• Blood cultures become positive 4
• Clinical deterioration occurs 1
• New concerning signs develop 1

Critical Pitfall to Avoid

The most important complication during neonatal lumbar puncture is unrecognized compromise of respiratory status 2. Continuous monitoring of respiratory function is essential, as neonates may not tolerate positioning well and the procedure itself can compromise breathing 4, 2.

The yield of lumbar puncture in asymptomatic neonates <72 hours is virtually zero, with studies showing hundreds of procedures needed to diagnose a single case 1, 4. However, in late-onset sepsis or symptomatic neonates, LP remains crucial as approximately 10% of septic babies with meningitis have negative blood cultures, making LP the only positive diagnostic test 4.