Encephalitis is inflammation of the brain tissue, most often caused by a virus such as herpes simplex, and less often by an autoimmune reaction. It is a medical emergency: the client may have fever, headache, confusion, behavior changes, and seizures. It is a medical diagnosis, not a nursing diagnosis; the nursing diagnoses used most often are Acute Confusion, Hyperthermia, Risk for Aspiration, and Acute Pain. The nurse watches neurological status closely, reports any decline at once, gives antiviral therapy on time, prevents injury during seizures, and protects the airway.
At a glance
- What it is
- Inflammation of the brain itself. When the meninges are also inflamed it is called meningoencephalitis.
- Main causes
- Viruses (herpes simplex is the most common cause of severe sporadic cases; also varicella-zoster, enteroviruses, and mosquito- or tick-borne viruses such as West Nile), autoimmune encephalitis (for example anti-NMDA receptor), and, less often, bacteria, fungi, or parasites.
- Key signs
- Fever, headache, confusion or behavior change, decreased level of consciousness, seizures, speech or memory problems, and focal weakness.
- Nursing focus
- Frequent neuro checks, on-time IV antiviral therapy as ordered, seizure precautions, fever control, airway protection, and family support.
- Act now
- A falling Glasgow Coma Scale score, a new unequal or sluggish pupil, a seizure, or a change in breathing pattern — call the provider or rapid response team immediately.
Why encephalitis happens
In infectious encephalitis, a virus reaches the brain through the blood or along nerves. Herpes simplex virus (HSV-1 in adults) travels along nerves and typically damages the temporal and frontal lobes, the areas that control memory, behavior, and language. That is why confusion, personality change, word-finding trouble, and seizures are so common.
The infection and the body’s immune response cause swelling (cerebral edema), small areas of bleeding, and death of nerve cells. Because the skull cannot expand, swelling raises intracranial pressure (ICP). Rising ICP lowers blood flow to the brain and, if it keeps rising, can push brain tissue downward (herniation). Fever, seizures, low oxygen, and high carbon dioxide all increase the brain’s demand or blood volume and make swelling worse.
In autoimmune encephalitis, antibodies attack proteins on nerve cells. It can follow an infection, including HSV encephalitis, or be linked to a tumor. It often starts with psychiatric symptoms, memory loss, seizures, or abnormal movements and is treated with immune therapy rather than antivirals.
Early treatment changes the outcome. Antiviral therapy for suspected HSV encephalitis is started as soon as the diagnosis is suspected, without waiting for test results, because delays are linked to more deaths and more lasting brain damage.
How encephalitis is diagnosed
| Test | What it shows | Nursing point |
|---|---|---|
| Lumbar puncture (CSF analysis) | Viral pattern: raised white cells (mostly lymphocytes), raised protein, usually normal glucose. PCR testing for HSV and other viruses | Position the client, monitor the site and neuro status afterward. Imaging may be done first if ICP is suspected |
| MRI of the brain | Swelling or changes in the affected lobes (temporal lobes in HSV) | Screen for metal implants; the client may need sedation or close monitoring |
| EEG | Abnormal electrical activity and seizures, including seizures with no visible movement | Report subtle signs such as staring, twitching, or a sudden drop in responsiveness |
| Blood tests | CBC, electrolytes (especially sodium), kidney function, blood cultures, and antibody tests for autoimmune causes | Kidney function also guides antiviral dosing |
Nursing assessment
Subjective data
- Headache: onset, severity, and whether it is getting worse
- Fever, chills, fatigue, and recent flu-like or cold-sore illness
- Sensitivity to light, nausea, or vomiting
- Family report of confusion, odd behavior, memory loss, or hallucinations
- Unusual smells or tastes, staring spells, or other possible seizures
- Recent travel, mosquito or tick bites, animal exposure, and vaccination history
- Immune status: HIV, chemotherapy, transplant, or steroid use
Objective data
- Level of consciousness and Glasgow Coma Scale (GCS) score, trended over time
- Orientation, attention, speech, and ability to follow commands
- Pupil size, equality, and reaction to light
- Strength and movement of all four limbs; new one-sided weakness
- Seizure activity, including subtle twitching or staring
- Temperature, heart rate, blood pressure, respiratory rate and pattern, and oxygen saturation
- Neck stiffness and light sensitivity (suggest meningeal involvement)
- Cough, gag, and swallow; secretions; lung sounds
- Intake and output, urine output, and kidney function results during antiviral therapy
- Serum sodium as ordered (low sodium from SIADH can worsen brain swelling and cause seizures)
Nursing diagnoses used with encephalitis
- Acute Confusion — sudden changes in attention, thinking, and level of consciousness
- Hyperthermia — fever from infection and inflammation, which raises the brain’s oxygen demand
- Risk for Aspiration — reduced consciousness, seizures, and a weak cough or gag
- Acute Pain — headache, neck stiffness, and light sensitivity
- Decreased Intracranial Adaptive Capacity — when ICP is being monitored and rises with care or stimulation
- Risk for Adult Falls — confusion, weakness, and seizures
- Impaired Verbal Communication and Impaired Memory — damage to language and memory areas
- Anxiety and Interrupted Family Processes — sudden, severe illness and an uncertain recovery
Worked care plans
Four plans in the same ADPIE shape. The scenario is a 58-year-old woman brought in by her husband after two days of fever and headache. This morning she did not recognize him, kept repeating the same questions, and had a seizure in the ambulance that stopped on its own. Temperature is 39.2°C (102.6°F) and her GCS is 13. HSV encephalitis is suspected, and the provider has ordered IV acyclovir, a lumbar puncture, an MRI, and an EEG.
1. Acute Confusion
Problem-focusedSubjective: “Where am I? Why are you keeping me here?” Husband says, “She’s never been like this. She keeps asking the same thing.”
Objective: GCS 13 (eyes open to voice, confused speech, obeys commands). Oriented to name only. Cannot keep attention long enough to answer questions. Pulls at her IV line. Pupils equal and reactive. Moves all limbs equally.
Acute Confusion related to brain inflammation and fever, as evidenced by disorientation to place and time, poor attention, repetitive questioning, and pulling at the IV line.
- Any decline in neurological status is found and reported at once
- Client remains free from injury and keeps her IV line in place
- GCS score and orientation return toward her baseline as treatment works
- Perform neuro checks (GCS, pupils, limb strength, speech) at the frequency ordered, using the same method as the previous nurse for a fair comparison
- Report any drop in GCS score, a new pupil change, or new weakness immediately
- Give IV acyclovir on time as ordered; a late dose delays treatment of a brain infection
- Keep the room quiet with soft lighting, and limit visitors to one or two familiar people
- Reorient her in short, simple sentences; explain each care step before touching her
- Ask her husband to stay and bring familiar items; family presence often calms the client
- Protect the IV site with a cover or sleeve and keep lines out of sight; use restraints only as a last resort and per policy
- Keep the bed low with side rails per seizure precaution policy and the call light in reach
Neuro checks stayed stable at GCS 13–14 over the first 24 hours with no pupil changes. Her IV line stayed in place with her husband at the bedside. By day 4 she was oriented to person and place. Goal partially met; continue plan.
2. Hyperthermia
Problem-focusedSubjective: “I’m so hot.” Husband says she has had a fever for two days and has hardly been drinking.
Objective: Temperature 39.2°C (102.6°F). Heart rate 112, respiratory rate 22. Skin hot and flushed. Dry lips. Dark, concentrated urine.
Hyperthermia related to the inflammatory response to brain infection and reduced fluid intake, as evidenced by a temperature of 39.2°C (102.6°F), tachycardia, tachypnea, and hot, flushed skin.
- Temperature falls toward the normal range within the time the provider expects
- Heart rate and respiratory rate return toward her baseline
- Urine output stays adequate and kidney function stays stable during acyclovir therapy
- Check temperature at the frequency ordered and recheck after each antipyretic dose
- Give antipyretics as ordered, checking the total daily dose from all sources
- Use light bedding, a cool room, and a cooling blanket if ordered; stop cooling if she starts to shiver
- Give IV fluids as ordered and record intake and output; report low urine output
- Monitor kidney function results as ordered, because acyclovir can damage the kidneys, especially when the client is dehydrated
- Report a fever that does not respond to treatment
Temperature fell to 37.8°C (100.0°F) by 24 hours and stayed below 38°C (100.4°F) from day 2. Heart rate was 88. Urine output was adequate and creatinine stayed stable. Goal met; continue to monitor.
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3. Risk for Aspiration
Risk diagnosis- Decreased level of consciousness (GCS 13)
- A seizure before admission, with a risk of more
- Confusion that limits her ability to follow swallowing instructions
- Weak cough when drowsy; swallow screen not yet done
No “as evidenced by” — this names a problem that has not happened yet. Her lungs are clear and oxygen saturation is normal.
Risk for Aspiration related to decreased level of consciousness, seizure activity, and impaired ability to follow swallowing instructions.
- Airway stays open and lungs stay clear throughout the stay
- Client has no aspiration during any seizure
- Client eats only after a swallow screen shows it is safe
- Keep her nothing by mouth until a swallow screen is passed per facility policy; request a speech-language pathology evaluation if she fails
- Keep the head of the bed raised as ordered (often 30 degrees) and her head and neck in line
- Keep working suction and oxygen at the bedside
- During a seizure: stay with her, turn her on her side, do not put anything in her mouth, time the seizure, and give oxygen and medicines as ordered
- Call for help at once if a seizure lasts 5 minutes or longer, or if seizures repeat without recovery between them (status epilepticus)
- Give antiseizure medicines on time as ordered
- Assess lung sounds, oxygen saturation, and temperature for signs of aspiration pneumonia
She had one brief seizure on day 1, was turned on her side, and kept her airway clear. She passed a bedside swallow screen on day 3 and started a soft diet. Lungs stayed clear with no fever from aspiration. Risk not realized; continue plan.
4. Acute Pain
Problem-focusedSubjective: “My head is pounding.” Rates headache 7 out of 10. Asks for the lights to be turned off.
Objective: Grimaces and shields her eyes from light. Holds her neck stiffly. Restless.
Acute Pain related to brain and meningeal inflammation, as evidenced by a reported headache of 7 out of 10, light sensitivity, grimacing, and guarding of the neck.
- Client reports pain at or below her stated comfort goal within the time expected for the treatment given
- Client rests quietly without grimacing
- Pain treatment does not mask changes in neurological status
- Assess pain with a number scale when she can use one, and a behavioral pain tool when she cannot
- Give analgesics as ordered; report a headache that is suddenly worse, which can signal rising ICP
- Do a neuro check before giving sedating medicines, and reassess afterward, so a change in consciousness is not blamed on the drug
- Dim the lights, reduce noise, and cluster care to allow rest
- Position for comfort with the head of the bed raised as ordered
- Reassess pain after each intervention at the time your facility’s policy requires
Headache fell to 3 out of 10 within an hour of treatment and stayed at 2–3 out of 10 by day 3. She rested with the lights dimmed. Neuro checks stayed stable. Goal met; continue plan.
Interventions and rationales
Client and family teaching
- Recovery from encephalitis can take months; tiredness, memory problems, mood changes, and trouble concentrating are common
- Take antiseizure medicines exactly as prescribed and do not stop them suddenly
- Do not drive until your provider says it is safe; driving rules after a seizure vary by state
- Keep follow-up visits with neurology and rehabilitation services
- Call your provider or emergency services for a new seizure, a severe headache, new confusion, or a fever that returns
- Prevent mosquito and tick bites with insect repellent, long sleeves, and checking for ticks after outdoor activity
- Keep vaccinations up to date, including measles, mumps, rubella, and varicella, and travel vaccines when advised
- Ask about support groups and counseling for survivors and families; personality and memory changes can be hard for everyone
- Use reminders, lists, and a set daily routine to help with memory at home
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A client with herpes simplex encephalitis is receiving IV acyclovir. Which finding should the nurse report to the provider first?
Why A. A falling GCS score with a new pupil change suggests rising intracranial pressure and possible herniation, which needs immediate action. A low-grade temperature that is coming down, a headache that is improving, and stable kidney function show the plan is working. Prep also explains why each wrong option looks reasonable.
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Frequently asked questions
What is the nursing diagnosis for encephalitis?
Encephalitis is a medical diagnosis, so it goes in the “related to” part. Common nursing diagnoses are Acute Confusion, Hyperthermia, Risk for Aspiration, Acute Pain, Decreased Intracranial Adaptive Capacity, and Risk for Adult Falls.
What is the nursing priority for a client with encephalitis?
Airway and neurological status come first: protect the airway, watch closely for a falling level of consciousness or pupil changes, manage seizures, and give antiviral therapy on time.
What is the difference between encephalitis and meningitis?
Meningitis is inflammation of the membranes that cover the brain and spinal cord; it typically causes headache, fever, and a stiff neck. Encephalitis is inflammation of the brain itself, so confusion, behavior change, and seizures are more prominent. The two can occur together.
Why is acyclovir started before test results come back?
Herpes simplex encephalitis is the most common treatable cause of severe viral encephalitis, and delays in treatment worsen outcomes. Acyclovir is started as soon as encephalitis is suspected and stopped later if tests rule out HSV.
What does the nurse monitor during IV acyclovir therapy?
Kidney function, urine output, and hydration, because acyclovir can cause kidney injury. Also watch the IV site and neurological status. The dose is set by the provider and adjusted for weight and kidney function.
Is encephalitis contagious?
Encephalitis itself is not usually spread from person to person, but some of the viruses that cause it can be. Mosquito- and tick-borne viruses spread through bites. Follow your facility’s isolation policy until the cause is known.
References
- Herdman, T. H., Kamitsuru, S., & Lopes, C. T. (Eds.). NANDA International Nursing Diagnoses: Definitions and Classification, 2024–2026. Thieme.
- Tunkel, A. R., et al. The management of encephalitis: clinical practice guidelines by the Infectious Diseases Society of America. Clinical Infectious Diseases, 2008;47(3):303–327.
- Venkatesan, A., et al. Case definitions, diagnostic algorithms, and priorities in encephalitis: consensus statement of the International Encephalitis Consortium. Clinical Infectious Diseases, 2013;57(8):1114–1128.
- Ellul, M., & Solomon, T. Acute encephalitis – diagnosis and management. Clinical Medicine, 2018;18(2):155–159.
- Graus, F., et al. A clinical approach to diagnosis of autoimmune encephalitis. The Lancet Neurology, 2016;15(4):391–404.
- Harding, M. M., Kwong, J., & Hagler, D. Lewis’s Medical-Surgical Nursing: Assessment and Management of Clinical Problems, 12th ed. Elsevier, 2023.
Neuro check frequency and escalation triggers, head-of-bed angle, temperature and oxygen targets, antiviral and antiseizure drugs and doses, infusion times, fluid orders, sodium monitoring, isolation precautions, and swallow screening methods vary by client, by provider, and by facility. Follow the provider’s written orders and your own institution’s policies. This page supports study and does not replace course instruction or clinical judgment.
