Why encephalitis is an emergency. Encephalitis is inflammation of brain tissue that can progress from fever and headache to seizures, coma, respiratory failure, raised intracranial pressure and permanent neurological disability. Viral, bacterial, parasitic, fungal, autoimmune and post-infectious causes can look similar at first. The EMT must protect the airway, check glucose, stop seizures, recognise meningitis/encephalitis, arrange urgent hospital care and avoid delays for a complete diagnostic work-up.
1. Learning objectives
- Define encephalitis and distinguish it from meningitis, encephalopathy and seizure-related confusion.
- Recognise common infectious, autoimmune, toxic and metabolic causes.
- Perform a safe ABCDE and neurological assessment, including glucose and seizure status.
- Identify raised intracranial pressure, impending herniation and respiratory failure.
- Explain urgent testing, lumbar-puncture precautions, empiric therapy and supportive care.
- Plan nursing monitoring, rehabilitation, infection prevention and family education.
2. Definition and pathophysiology
Encephalitis is inflammation of the brain parenchyma causing neurological dysfunction. Meningoencephalitis affects both brain tissue and meninges. Encephalopathy is broader brain dysfunction from systemic or metabolic causes and may occur without inflammation. Brain swelling, inflammatory injury, seizures, impaired consciousness and disruption of cerebral perfusion can cause secondary neuronal damage.
In Uganda and other tropical settings, the differential includes herpes simplex virus, varicella-zoster, arboviruses, enteroviruses, measles, HIV-related infections, bacterial meningitis with brain involvement, cerebral malaria, tuberculosis, cryptococcosis, autoimmune encephalitis, toxins, hypoglycaemia, electrolyte disturbance and post-infectious disease.
Do not wait for classic neck stiffness. A patient with fever plus new confusion, personality change, seizure, focal deficit or reduced consciousness needs urgent evaluation even when the neck is supple.
3. Causes and clinical clues
| Cause/group | Clues | Emergency implications |
|---|---|---|
| HSV-1/HSV-2 encephalitis | Fever, headache, confusion, seizures, personality/language change, focal deficits; temporal-lobe features | Empiric IV acyclovir is time-critical when suspected, with renal monitoring. |
| VZV and other viruses | Rash, cranial neuropathy, ataxia, immunosuppression or recent viral illness | Isolation when indicated and specialist antiviral pathway. |
| Arboviral encephalitis | Seasonal/vector exposure, fever, tremor, weakness, movement disorder or flaccid paralysis | Supportive critical care and vector/public-health notification. |
| Bacterial meningoencephalitis | Fever, meningism, shock, purpura, rapid deterioration or focal infection | Immediate empiric antibacterial therapy; droplet precautions for suspected meningococcal disease. |
| Cerebral malaria | Endemic exposure, coma, seizures, hypoglycaemia, anaemia or jaundice | Urgent malaria testing and parenteral antimalarial pathway. |
| TB/fungal/parasitic disease | Subacute illness, weight loss, HIV/immunosuppression, cranial neuropathies | Specialist testing and prolonged therapy; raised ICP may make LP unsafe. |
| Autoimmune/paraneoplastic encephalitis | Psychiatric change, memory loss, dyskinesia, autonomic instability or seizures without infection source | Exclude infection first; specialist immunotherapy and seizure management. |
| Toxic/metabolic encephalopathy | Hypoglycaemia, sodium abnormality, poisoning, liver/renal failure, heat illness or drug effect | Correct reversible cause while continuing neurological assessment. |
4. Recognition and red flags
Urgent resuscitation/red flags: GCS falling, repeated or ongoing seizure, focal weakness, unequal pupils, papilloedema, Cushing response, severe headache with vomiting, abnormal posturing, respiratory irregularity, hypoxia, shock, hypoglycaemia, purpura, pregnancy, immunocompromise, recent neurosurgery or a rapidly progressive course.
- Fever or recent infection plus altered mental status is a high-risk combination.
- Seizures may be subtle: eye deviation, facial twitching, automatisms, unexplained agitation or failure to regain baseline consciousness.
- Normal blood pressure or temperature does not exclude severe intracranial disease.
5. History taking
- Time and sequence of fever, headache, vomiting, confusion, behaviour change, seizures and focal weakness.
- Witness description: onset, duration, movements, eye position, cyanosis, incontinence, injury and recovery after a seizure.
- Recent infections, rash, ear/sinus infection, animal/mosquito/tick exposure, travel, vaccines and sick contacts.
- HIV status, TB exposure, immunosuppression, cancer, pregnancy and recent medications or toxins.
- Diabetes, renal/liver disease, epilepsy, sickle cell disease, malaria exposure and antimalarial use.
- Recent neurosurgery, head trauma, lumbar puncture, injection drug use or invasive procedure.
6. ABCDE and neurological assessment
A – Airway
- Assess gag/cough, secretions, vomiting, tongue obstruction and aspiration. Use jaw thrust/positioning, suction and airway adjuncts as trained; prepare an experienced airway team for GCS decline.
B – Breathing
- Check respiratory rate, SpO₂, effort and pattern. Central hypoventilation, aspiration, seizures or raised ICP can cause respiratory failure; give oxygen for hypoxaemia.
C – Circulation
- Check pulse, blood pressure, capillary refill, temperature and urine output. Treat shock cautiously with isotonic fluid and investigate sepsis, bleeding and dehydration.
- Obtain IV access and blood samples only when safe; do not delay time-critical therapy.
D – Disability
- Record GCS/AVPU, pupils, limb power, speech, facial symmetry, sensation and glucose. Repeat after seizure treatment or any deterioration.
E – Exposure
- Look for rash, petechiae, trauma, needle marks, ear/mastoid infection, shingles, bites and signs of systemic infection while protecting dignity and warmth.
7. Seizure and airway emergencies
- Protect from injury, clear nearby objects and time the seizure; do not restrain or put anything in the mouth.
- Place in a safe lateral position when possible, suction secretions with PPE and give oxygen.
- Check glucose as soon as feasible and treat hypoglycaemia under protocol.
- For ongoing convulsive status, give a protocol-selected benzodiazepine and escalate for second-line therapy/airway support.
- After the seizure, reassess GCS, pupils, breathing, temperature, glucose, focal signs and injuries.
- Persistent coma after a seizure is not automatically “post-ictal”; consider ongoing non-convulsive seizure, encephalitis, malaria, hypoxia, toxic/metabolic causes or raised ICP.
8. Raised intracranial pressure and herniation
- Warning signs include deteriorating consciousness, repeated vomiting, worsening headache, unequal or sluggish pupils, new focal deficit, abnormal posturing, bradycardia with hypertension and irregular breathing.
- Keep the head midline and elevate about 30 degrees if perfusion permits; avoid neck compression, hypoxia, hypotension, fever and unnecessary stimulation.
- Maintain oxygenation and normoglycaemia; treat seizures promptly.
- Urgently involve anaesthesia/critical care/neurosurgery. Do not perform lumbar puncture when there are signs of mass effect, severe reduced consciousness, focal deficit, papilloedema, uncontrolled seizure or cardiorespiratory instability until senior review.
- Hyperventilation is not routine; use only as a temporary specialist-directed rescue for impending herniation.
9. Investigations and lumbar-puncture safety
| Test | Purpose | Safety/interpretation |
|---|---|---|
| Glucose, FBC, electrolytes, renal/liver tests, malaria test | Find reversible/metabolic causes, cerebral malaria and organ dysfunction | Correct abnormalities promptly; a negative malaria test does not exclude encephalitis. |
| Blood cultures | Identify bacterial, fungal or bloodstream infection | Collect before antibiotics only if it will not delay treatment. |
| CT/MRI brain | Mass lesion, oedema, haemorrhage, stroke, abscess or temporal-lobe changes | Imaging does not replace empiric therapy; stabilise first. |
| Lumbar puncture and CSF | Cells, protein, glucose, Gram stain/culture, PCR and targeted tests | Perform promptly when safe; defer for raised ICP, unstable airway/breathing/circulation, focal mass-effect signs or severe coagulopathy. |
| EEG | Non-convulsive seizures, encephalopathy pattern and prognosis | Do not delay treatment of clinical status epilepticus while waiting. |
| Targeted PCR/serology | HSV/VZV, arbovirus, HIV, TB, autoimmune and other causes | Choose tests by epidemiology, syndrome and specialist advice. |
10. Immediate hospital management
- Admit to a monitored area; use isolation precautions appropriate to the suspected pathogen.
- Stabilise airway, breathing and circulation; avoid hypoxia, hypotension, hypoglycaemia and hyperthermia.
- Start empiric IV acyclovir promptly when HSV encephalitis is clinically suspected, with renal-dose and hydration monitoring; do not wait for CSF PCR.
- If bacterial meningitis/meningoencephalitis is possible, give empiric IV antibacterial therapy and corticosteroid according to local/WHO protocol, ideally after blood cultures and LP only when safe.
- Treat severe malaria immediately through the parenteral artesunate pathway when indicated.
- Manage seizures, electrolyte abnormalities, fever, pain, agitation and aspiration risk.
- Consult infectious diseases, neurology, critical care, paediatrics/obstetrics and public health as appropriate.
11. Supportive and critical-care management
- Use continuous pulse oximetry and frequent neurological observations; document GCS and pupil trend.
- Provide enteral nutrition when airway is protected; manage aspiration and pressure-injury risk.
- Use isotonic fluids for shock or dehydration but avoid fluid overload in raised ICP, renal failure or cardiac disease.
- Control fever with paracetamol and safe environmental measures; investigate the cause rather than masking deterioration.
- Prevent venous thromboembolism and stress ulcers according to critical-care protocol, balancing bleeding risk.
- Monitor sodium closely; rapid correction of severe dysnatremia can worsen neurological injury.
- Escalate for invasive ventilation, vasopressor support, intracranial-pressure management or transfer to ICU.
12. Nursing care plan
| Problem | Interventions | Outcome/alert |
|---|---|---|
| Reduced consciousness/airway risk | Side positioning, suction, airway observations, aspiration precautions, GCS/pupil checks | Airway protected; immediate escalation for falling GCS or irregular breathing |
| Seizure risk | Padded surroundings, oxygen/suction ready, seizure chart, medication timing and recovery assessment | Seizure stops and patient returns toward baseline |
| Raised ICP | Head midline/elevated, quiet environment, prevent hypoxia/hypotension/fever, frequent neuro observations | No new pupil asymmetry, posturing or deterioration |
| Infection transmission | Hand hygiene, droplet/contact precautions when indicated, safe specimen and waste handling | No staff or patient cross-infection |
| Immobility/nutrition | Pressure-area care, passive movement, feeding/swallow review and fluid balance | Skin intact, adequate nutrition and no aspiration |
| Family distress | Simple explanations, updates, consent/confidentiality and rehabilitation planning | Family understands warning signs and follow-up |
13. Infection prevention and public-health issues
- Use droplet precautions for suspected meningococcal disease until the appropriate period after effective antibiotics; use pathogen-specific precautions for VHF, measles, varicella or other transmissible causes.
- Use standard precautions for blood, CSF, vomit, urine and respiratory secretions; handle sharps safely.
- Notify public health for suspected vaccine-preventable disease, VHF, meningococcal clusters or unusual encephalitis.
- Consider mosquito/tick control and vaccination advice where arboviral or vaccine-preventable causes are suspected.
14. Recovery, rehabilitation and prevention
- Assess memory, speech, swallowing, mood, behaviour, movement, hearing and vision before discharge.
- Arrange physiotherapy, occupational therapy, speech/swallow therapy, neuropsychology and seizure follow-up as needed.
- Teach family seizure first aid, medication adherence, driving/work restrictions and return precautions.
- Complete vaccination, mosquito protection, HIV/TB care and exposure prevention according to the cause.
- Monitor for post-encephalitic epilepsy, cognitive impairment, fatigue, depression, sleep disturbance and focal deficits.
15. Clinical scenarios
Scenario 1 – Fever and confusion. A 24-year-old develops fever, personality change, aphasia and a focal seizure. The EMT protects the airway, gives oxygen, checks glucose, treats the seizure under protocol, obtains urgent IV access and alerts the clinician that HSV encephalitis is possible. CT/LP and empiric therapy are organised in parallel; acyclovir is not delayed while waiting for CSF.
Scenario 2 – Suspected meningitis with shock. A patient has fever, neck stiffness, purpuric rash, hypotension and confusion. The team uses droplet precautions, ABCDE resuscitation, blood cultures, urgent empiric antibacterial therapy and senior/critical-care referral. Lumbar puncture is deferred until the patient is stable and contraindications are reviewed.
Scenario 3 – Post-seizure coma. A child remains unresponsive 20 minutes after a seizure. The EMT rechecks glucose, oxygenation, temperature, pupils and seizure activity rather than assuming a normal post-ictal state. Persistent non-convulsive status, cerebral malaria, meningitis and raised ICP remain possible.
16. Common errors
- Waiting for neck stiffness before considering encephalitis.
- Calling persistent coma “post-ictal” without checking glucose and ongoing seizures.
- Delaying acyclovir or antibiotics for imaging/LP when clinical suspicion is high.
- Performing LP in a patient with raised ICP, shock, severe coagulopathy or a deteriorating airway.
- Ignoring cerebral malaria and hypoglycaemia in endemic settings.
- Giving excessive fluids or allowing fever, hypoxia, hypotension and hyponatraemia to persist.
- Failing to plan rehabilitation and family education after survival.
17. Quick revision questions
- What clinical features make encephalitis likely?
- List four infectious and three non-infectious causes.
- What are the first actions during an active seizure?
- When should lumbar puncture be deferred?
- Why is empiric acyclovir time-critical?
- How can cerebral malaria be distinguished and treated urgently?
- What findings suggest raised ICP or impending herniation?
- Which observations should nursing staff trend?
- When are droplet or other transmission-based precautions needed?
- What rehabilitation needs must be assessed before discharge?
18. Key takeaways
BRAIN SAFE:
Breathing and airway first | Recognise fever plus altered mentation | Antivirals/antibiotics early when indicated | Investigate glucose, malaria, CSF and imaging safely
Seizures treated and timed | Avoid unsafe LP | Fight hypoxia, hypotension and fever | Escalate to critical care and rehabilitation
Breathing and airway first | Recognise fever plus altered mentation | Antivirals/antibiotics early when indicated | Investigate glucose, malaria, CSF and imaging safely
Seizures treated and timed | Avoid unsafe LP | Fight hypoxia, hypotension and fever | Escalate to critical care and rehabilitation