What is the management approach for a patient with viral encephalitis to prevent complications such as stroke or cerebral edema?

Management of Viral Encephalitis to Prevent Stroke and Cerebral Edema

Patients with viral encephalitis require urgent ICU assessment for airway protection, ventilatory support, management of raised intracranial pressure, optimization of cerebral perfusion pressure, and correction of electrolyte imbalances to prevent complications such as stroke and cerebral edema. 1, 2

Initial Assessment and Stabilization

• Immediate neurological consultation: All patients with suspected viral encephalitis should have access to neurological specialist opinion within 24 hours 1
• Airway management: Patients with declining consciousness require immediate intubation to protect airway 1, 2
• Monitoring: Close monitoring in neurological ward, high dependency unit, or intensive care unit based on severity 1

Diagnostic Workup to Guide Management

Neuroimaging

• MRI is preferred: Should be performed within 24 hours of admission, certainly within 48 hours 1
  • More sensitive than CT for early detection of viral encephalitis changes (90% vs 25% sensitivity) 1
  • Diffusion-weighted imaging is especially sensitive for early changes 1
• CT scan if MRI unavailable: Useful to exclude structural causes of raised intracranial pressure or alternative diagnoses 1
  • Important to rule out brain shift before lumbar puncture 1

Lumbar Puncture

• Perform LP unless contraindicated by clinical signs of raised intracranial pressure 1
• Contraindications to immediate LP include:
  • New seizures
  • Focal neurological signs
  • Moderate to severe impairment of consciousness (GCS ≤10)
  • Papilledema 1

EEG

• Not routinely required in all cases but indicated for:
  • Patients with mildly altered behavior to distinguish psychiatric from organic causes
  • Suspected subtle motor or non-convulsive seizures 1

Specific Management Based on Viral Etiology

Herpes Simplex Virus (HSV) Encephalitis

• Acyclovir: Start immediately at 10 mg/kg IV three times daily (for adults) 3
• Duration: Typically 14-21 days 3

Varicella-Zoster Virus (VZV) Encephalitis

• Acyclovir: 10-15 mg/kg IV three times daily 1
• Consider corticosteroids: Particularly if there is evidence of vasculopathy (stroke) 1

Enterovirus Encephalitis

• No specific treatment routinely recommended
• In severe cases, consider:
  • Pleconaril (if available)
  • Intravenous immunoglobulin 1

Management of Cerebral Edema and Raised Intracranial Pressure

• Elevation of head: Keep head elevated at 30 degrees
• Maintain adequate cerebral perfusion pressure: Target CPP >60 mmHg
• Avoid hyperthermia: Maintain normothermia
• Manage seizures: Prompt treatment of seizures to prevent further increases in ICP
• Osmotic therapy: Mannitol or hypertonic saline for acute increases in ICP
• Consider corticosteroids: Controversial but may be beneficial in patients with marked cerebral edema, brain shift, or raised intracranial pressure 1
• Surgical decompression: Consider in cases of impending uncal herniation or increased ICP refractory to medical management 3

Prevention of Stroke in Viral Encephalitis

• Recognize stroke mimics: HSV encephalitis can present with focal neurological deficits resembling stroke 4, 5
• Monitor for vasculopathy: Particularly with VZV encephalitis which can cause large vessel vasculopathy 1
• Maintain euvolemia: Avoid dehydration which can increase risk of thrombosis
• Optimize blood pressure: Maintain adequate cerebral perfusion pressure

Follow-up Care

• Do not discharge patients without a definite or suspected diagnosis 1
• Arrange outpatient follow-up and plans for ongoing therapy and rehabilitation 1
• All patients should have access to assessment for rehabilitation 1

Pitfalls and Caveats

• Viral encephalitis can mimic stroke, especially HSV encephalitis with unilateral brain lesions 4, 5
• Unselected CT scanning before LP can cause unnecessary delays in diagnosis and treatment 1
• Clinical assessment rather than CT scanning should determine the safety of performing LP 1
• Deterioration in consciousness level after LP has been reported in patients with bacterial meningitis despite normal CT, though this appears less common in viral encephalitis 1

By following this structured approach to management, complications such as stroke and cerebral edema can be minimized in patients with viral encephalitis.