What is the management of meningitis in a patient taking Lamictal (lamotrigine)?

Management of Lamotrigine-Associated Meningitis

If meningitis is suspected in a patient taking lamotrigine, the medication should be immediately discontinued and not reintroduced due to the risk of rapid recurrence with more severe symptoms upon rechallenge. 1

Initial Assessment and Management

Immediate Actions

• Stabilize airway, breathing, and circulation
• Obtain blood cultures within 1 hour of arrival at hospital 2
• Assess Glasgow Coma Scale (GCS) score 2
• Perform lumbar puncture (LP) within 1 hour if safe to do so 2, 3
• Start empiric antimicrobial therapy immediately after LP is performed (or after blood cultures if LP is delayed) 2, 3

Diagnostic Workup

• Complete blood count with differential
• CSF analysis (cell count, protein, glucose, Gram stain, culture)
• Note: CSF profiles in lamotrigine-associated meningitis may show features of both bacterial and viral meningitis 1
• Document recent medication history, specifically lamotrigine use and timing

Treatment Protocol

Empiric Antimicrobial Therapy

For adults <60 years:

• Cefotaxime 2g IV every 6 hours OR
• Ceftriaxone 2g IV every 12 hours 2

For adults ≥60 years:

• Cefotaxime 2g IV every 6 hours OR
• Ceftriaxone 2g IV every 12 hours PLUS
• Amoxicillin 2g IV every 4 hours 2

Adjunctive Therapy

• Dexamethasone 10mg IV every 6 hours, started before or with first antimicrobial dose 2, 3
• Continue dexamethasone for 4 days if pneumococcal meningitis is confirmed 2
• Stop dexamethasone if another cause of meningitis is confirmed 2

Lamotrigine-Specific Considerations

Recognition of Lamotrigine-Associated Aseptic Meningitis

• Typically occurs within 1-2 weeks of starting lamotrigine 4, 5
• Presents with fever, headache, neck stiffness similar to bacterial meningitis 6
• Rapid recurrence of symptoms upon rechallenge (median time to onset: 60 minutes) 1

Management of Lamotrigine-Associated Meningitis

1. Immediately discontinue lamotrigine 6, 4, 1
2. Provide supportive care:
   • Antipyretics for fever
   • Analgesics for headache
   • Maintain euvolemia (avoid fluid restriction) 3
3. Continue empiric antimicrobial therapy until cultures are negative and clinical improvement is observed
4. Do not reintroduce lamotrigine due to high risk of recurrence (nearly 40% of cases report positive rechallenge) 1

Intensive Care Considerations

ICU Admission Criteria

• GCS <12
• Persistent seizures
• Evidence of severe sepsis or shock
• Hypoxia
• Signs of raised intracranial pressure 2, 3

Critical Care Management

• Consider intubation for patients with GCS <12 2, 3
• Maintain mean arterial pressure ≥65 mmHg 3
• Monitor for clinical deterioration 3

Follow-up and Prevention

• Monitor for resolution of symptoms after lamotrigine discontinuation
• Consider alternative anticonvulsant therapy (e.g., levetiracetam) which has not been linked with aseptic meningitis 5
• Educate patient about avoiding lamotrigine in the future
• Document lamotrigine-associated meningitis in patient's allergy profile

Common Pitfalls and Caveats

• Failure to recognize lamotrigine as a potential cause of aseptic meningitis can lead to unnecessary prolonged antimicrobial therapy
• Lamotrigine-associated meningitis is likely underrecognized 4
• Rechallenge with lamotrigine can cause rapid recurrence of symptoms, often more severe than the initial presentation 6, 4, 1
• CSF findings may mimic both bacterial and viral meningitis, leading to diagnostic confusion 1
• Lamotrigine-associated meningitis should be included in the differential diagnosis of culture-negative meningitis 1