👤 By the CinnaRN Clinical Content Team🕐 Updated 2026-08-23🏷️ Physiological Adaptation🔖 Free to read, print, and share
Also known as: brain inflammation · viral brain infection
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Use this quick-reference guide to spot, treat, and prevent Encephalitis on the NCLEX. Keep it handy during review and on exam day!
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📒 The 1-minute cheat sheet
⚠️ Cause
Viral (HSV), mosquito-borne
Brain tissue inflammation
🩺 Signs
Fever, severe HA, ↓LOC
Seizures, confusion
Focal neuro deficits
✅ Do
Acyclovir if HSV
Monitor ICP, neuro checks
Seizure precautions
🚩 Report
↑ICP: ↓LOC, ↑BP, ↓HR
New seizures, pupil changes
📚 Encephalitis — full study notes
The cheat sheet above is your quick recall card. These notes go deeper — what it is, what to do first, what must be reported, and what to teach.
Encephalitis is inflammation of the brain tissue (parenchyma) most often caused by a viral infection such as herpes simplex virus or arboviruses spread by mosquitoes (e.g., West Nile). Unlike meningitis, which inflames the meninges, encephalitis affects the brain itself, so altered mental status and focal neurologic deficits are prominent. It presents with fever, headache, altered level of consciousness, seizures, and behavioral changes. It is a medical emergency because of the risk of increased intracranial pressure and lasting neurologic damage.
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Key points
Understand these first
Caused mainly by viruses; herpes simplex virus is the most common sporadic cause and arboviruses (West Nile) spread through mosquito bites.
Hallmark is altered mental status (confusion, behavioral changes, decreased level of consciousness) along with fever, headache, seizures, and focal deficits.
Diagnosis relies on lumbar puncture (elevated lymphocytes, normal-to-elevated protein, normal glucose in viral cases), MRI, and PCR of cerebrospinal fluid.
IV acyclovir is started immediately and empirically when herpes simplex encephalitis is suspected, before confirmation, because early treatment reduces mortality.
Major complications include increased intracranial pressure, seizures, syndrome of inappropriate ADH, and permanent cognitive or motor deficits.
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Nursing priorities
What to do, in order
Perform frequent neurologic assessments and monitor for signs of increasing intracranial pressure.
Administer IV acyclovir promptly as ordered and ensure adequate hydration to protect the kidneys.
Institute seizure precautions and maintain a quiet, dimly lit environment to reduce stimulation.
Maintain the head of bed at about 30 degrees with the head midline to promote venous drainage and control ICP.
Monitor fluid balance, electrolytes, and intake/output for SIADH and dehydration.
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Red flags — report now
Escalate immediately
Declining level of consciousness, unequal or sluggish pupils, widening pulse pressure, bradycardia, or irregular respirations (Cushing triad) indicating rising intracranial pressure — notify provider now.
New or prolonged seizure activity (status epilepticus) requiring emergency intervention.
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Labs & values
Numbers to know
CSF in viral encephalitis: elevated lymphocytes, protein normal to mildly elevated, glucose normal
Normal CSF opening pressure: 5 to 15 mmHg (70 to 180 mm H2O)
Serum sodium 135 to 145 mEq/L — monitor for hyponatremia from SIADH
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Patient teaching
What patients must know
Complete the full course of antiviral therapy as prescribed.
Prevent mosquito-borne encephalitis by using insect repellent, wearing protective clothing, and avoiding standing water.
Report recurrent headache, confusion, seizures, or behavioral changes during recovery.
Understand that rehabilitation may be needed for residual cognitive or motor deficits.
Maintain follow-up appointments to monitor recovery and neurologic status.
❓ Encephalitis: NCLEX FAQs
What are the priority nursing interventions for Encephalitis?
Perform frequent neurologic assessments and monitor for signs of increasing intracranial pressure. Administer IV acyclovir promptly as ordered and ensure adequate hydration to protect the kidneys. Institute seizure precautions and maintain a quiet, dimly lit environment to reduce stimulation. Maintain the head of bed at about 30 degrees with the head midline to promote venous drainage and control ICP.
What are the warning signs of Encephalitis a nurse must report?
Declining level of consciousness, unequal or sluggish pupils, widening pulse pressure, bradycardia, or irregular respirations (Cushing triad) indicating rising intracranial pressure — notify provider now. New or prolonged seizure activity (status epilepticus) requiring emergency intervention.
What do I need to know about Encephalitis for the NCLEX?
Caused mainly by viruses; herpes simplex virus is the most common sporadic cause and arboviruses (West Nile) spread through mosquito bites. Hallmark is altered mental status (confusion, behavioral changes, decreased level of consciousness) along with fever, headache, seizures, and focal deficits. Diagnosis relies on lumbar puncture (elevated lymphocytes, normal-to-elevated protein, normal glucose in viral cases), MRI, and PCR of cerebrospinal fluid. IV acyclovir is started immediately and empirically when herpes simplex encephalitis is suspected, before confirmation, because early treatment reduces mortality.
What patient teaching is important for Encephalitis?
Complete the full course of antiviral therapy as prescribed. Prevent mosquito-borne encephalitis by using insect repellent, wearing protective clothing, and avoiding standing water. Report recurrent headache, confusion, seizures, or behavioral changes during recovery. Understand that rehabilitation may be needed for residual cognitive or motor deficits.
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Quick Tip
Caused mainly by viruses; herpes simplex virus is the most common sporadic cause and arboviruses (West Nile) spread through mosquito bites.