What is the recommended management for seizures in encephalitis?

Management of Seizures in Encephalitis

For patients with suspected encephalitis presenting with seizures, immediate treatment with acyclovir (10 mg/kg intravenously every 8 hours in adults and children with normal renal function; 20 mg/kg intravenously every 8 hours in neonates) should be initiated as soon as possible, pending diagnostic results, along with appropriate antiepileptic medications. 1

Initial Management of Seizures

• Patients with seizures in encephalitis require urgent assessment by neurological specialists and should be managed in a setting where clinical neurological review can be obtained within 24 hours of referral 2
• Patients with falling level of consciousness require immediate ICU assessment for airway protection, ventilatory support, and management of raised intracranial pressure 1, 3
• Access to neuroimaging (MRI preferred over CT) and neurophysiology (EEG) is essential for proper diagnosis and management of seizures 1, 2

Acute Seizure Management

• For active seizures or status epilepticus, first-line treatment includes benzodiazepines:
  • Lorazepam 0.1 mg/kg IV over 2-4 minutes 4
  • Midazolam may be used as an alternative, particularly in pre-hospital settings 5
• If seizures persist after benzodiazepine administration, second-line options include:
  • Levetiracetam 20 mg/kg IV over 15 minutes (may be preferred in patients with respiratory compromise or hypotension) 4, 5
  • Fosphenytoin or phenytoin (if fosphenytoin unavailable), though these carry risks of cardiac arrhythmias, hypotension, and tissue injury 5
  • Valproic acid IV as an alternative second-line agent 5

Etiology-Specific Management

• For herpes simplex virus encephalitis:
  • Acyclovir 10 mg/kg IV every 8 hours for 14-21 days in adults and children 1
  • Higher-dose acyclovir (20 mg/kg IV every 8 hours for 21 days) in neonates has shown decreased mortality to 5% 1
  • Consider repeat CSF PCR at the end of therapy if clinical response is inadequate 1
• For varicella-zoster virus encephalitis:
  • Acyclovir 10-15 mg/kg IV three times daily, with or without a short course of corticosteroids 1
  • If vasculitic component is present, stronger case for using corticosteroids 1
• For cytomegalovirus encephalitis:
  • Combination of ganciclovir (5 mg/kg IV every 12 hours) and foscarnet (60 mg/kg IV every 8 hours or 90 mg/kg IV every 12 hours) for 3 weeks 1

Long-Term Antiepileptic Management

• Risk factors for seizure relapse after acute encephalitis include:
  • Multiple seizures during acute phase 6
  • Temporal lobe involvement on imaging 6
  • Status epilepticus during acute phase 6
• For patients with only one seizure and no temporal lobe involvement, antiepileptic drugs may not be strictly necessary beyond the acute phase 6
• For patients with risk factors for seizure recurrence, consider maintenance therapy with:
  • Levetiracetam or sodium valproate for at least 3 months after the acute phase, as this is the peak time for relapse 6
• In autoimmune encephalitis:
  • Seizures often respond better to immunotherapy than to antiepileptic drugs alone 7, 8
  • Long-term antiepileptic treatment may not be needed in encephalitis with antibodies to neuronal extracellular antigens 8
  • Long-term treatment is usually required in encephalitis with antibodies against intracellular antigens 8

Monitoring and Follow-up

• All patients should have access to assessment for rehabilitation, as sequelae of encephalitis may not be immediately apparent at discharge 2
• Monitor for drug interactions between antimicrobials and antiepileptic medications 3
• EEG monitoring is essential in patients with altered mental status to detect subclinical seizures, which occur in approximately 50% of patients with encephalitis-related seizures 7

Special Considerations

• Adjunctive corticosteroids in herpes simplex encephalitis remain controversial; one retrospective study showed better outcomes in patients treated with corticosteroids, but results need confirmation before this can be recommended 1
• For refractory status epilepticus, consider continuous EEG monitoring and escalation to anesthetic agents under ICU care 3
• Seizure prognosis in most forms of encephalitis is generally favorable with appropriate treatment of the underlying cause 7