First Apparent Seizure (Adult, 16 Years or Older)
Adult after a possible first seizure who has recovered. Seizure lasting 5 minutes or more, or repeated seizures without recovery: use the status epilepticus pathway.
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NeurologyDiagnostic
First Unprovoked Seizure Evaluation in Adults
First Unprovoked Seizure Evaluation in Adults: First Apparent Seizure (Adult, 16 Years or Older) → First Assessment in All Patients: 12-Lead ECG, Glucos...
Pathway Overview
21 steps
Algorithm Steps
21 total
01Start 02Action First Assessment in All Patients: 12-Lead ECG, Glucose, Bloods
Do before deciding the cause. The 12-lead ECG looks for cardiac mimics that can be fatal.
- 12-lead ECG in every patient: long QT, Brugada pattern, pre-excitation, heart block, HCM
- Capillary glucose now; sodium, calcium, magnesium, urea and creatinine, LFTs, FBC
- Pregnancy test in every woman who could be pregnant
- Eyewitness history; examine for focal signs, head injury, tongue biting
- Toxicology and alcohol or drug history if suspected
- Suspected CNS infection: blood cultures and antibiotics now; CT brain before lumbar puncture after a seizure
03Warning Pregnant Over 20 Weeks or Up to 6 Weeks Postpartum: Treat as Eclampsia
Check pregnancy status in every woman who could be pregnant. Pregnant under 20 weeks: continue, with obstetric and neurology advice. Do not delay urgent CT for a red flag.
- Seizure over 20 weeks pregnant or up to 6 weeks postpartum (most within 48 hours): eclampsia until proven otherwise
- Give IV magnesium sulfate per the eclampsia protocol (SOMANZ 2023, 6.6); treat severe hypertension
- Urgent obstetric review; atypical features: consider venous sinus thrombosis, PRES, stroke
04Decision Epileptic Seizure Likely?
Use the eyewitness account, ECG and examination. Abnormal ECG, collapse on exertion or lying down, palpitations, or family history of sudden death: treat as possible cardiac syncope.
- Syncope, including cardiac arrhythmia (most common mimic)
- Psychogenic non-epileptic seizure
- Migraine with aura
- Transient ischaemic attack, transient global amnesia
- Movement disorders, sleep disorders
- If Yes
05Warning Red Flags: Urgent CT Brain Now
Any red flag: urgent CT brain in the emergency department before discharge.
- New focal deficit, persistent confusion or reduced conscious state, new severe headache
- Head injury, anticoagulant or bleeding disorder, cancer, immunosuppression
- Fever, neck stiffness or rash: treat as CNS infection now (meningitis pathway); do not delay antibiotics for CT or LP
06Decision Acute Symptomatic (Provoked) Seizure?
Provoked means a clear acute cause at the time of the seizure. Only severe metabolic changes count; milder changes: correct them, but continue the unprovoked work-up.
- Metabolic, within 24 hours: glucose under 2.0 or over 25 mmol/L, sodium under 115 mmol/L, total calcium under 1.25 mmol/L, magnesium under 0.33 mmol/L, urea over 35.7 mmol/L, creatinine over 884 µmol/L
- Acute brain insult within 7 days: stroke, head injury, CNS infection, bleed, brain surgery
- Alcohol or sedative withdrawal; drug toxicity
- No acute cause found: unprovoked
- If Yes
07Action Provoked Seizure: Treat the Cause
Treat the acute cause. Long-term antiseizure medication is usually not needed.
- Correct the metabolic cause; treat infection, stroke, bleed or head injury
- Alcohol withdrawal: use the alcohol withdrawal pathway
- Short-term antiseizure medication only on specialist advice during the acute illness
- Risk of later epilepsy is lower than after an unprovoked seizure
08Action Safety and Driving Advice for Every Patient
Do not drive until the licensing authority allows it. Australia: the patient must tell the driver licensing authority (Austroads). Other countries: follow local licensing law.
- Private licence (Austroads), first seizure or acute symptomatic seizure: conditional licence may be considered after at least 6 months with no seizures
- Private licence, ASM started: at least 6 months on treatment and no seizures in the last 6 months
- Commercial licence (Austroads): first seizure at least 5 years seizure-free, acute symptomatic seizure at least 12 months, plus EEG criteria, on epilepsy specialist advice
- No swimming or bathing alone (shower, not bath); avoid heights and unguarded machinery
- Avoid sleep deprivation and excess alcohol
- Call an ambulance (000 in Australia) if a seizure lasts 5 minutes or more, repeats without recovery, or causes injury
09Outcome Specialist Follow-up
First seizure clinic or neurologist reviews results and the diagnosis. Second unprovoked seizure more than 24 hours after the first: epilepsy; start ASM.
- Diagnosis uncertain: refer to an epilepsy specialist
- Epilepsy diagnosed: give information on SUDEP and seizure safety
If No10Action Unprovoked: Refer Urgently to First Seizure Clinic
Specialist assessment within 2 weeks. Assess the risk of a second seizure.
- Back to baseline, normal examination and tests: discharge is reasonable with safety and driving advice
- Give information on who to contact if another seizure occurs
- Ask about modifiable risks: sleep loss, alcohol, sepsis, mental health, vascular risk factors
11Action Brain Imaging: MRI Preferred
MRI with an epilepsy protocol, reported by a neuroradiologist.
- MRI brain with epilepsy protocol (NICE: within 6 weeks of referral)
- CT if MRI is unavailable or contraindicated; urgent CT if a red flag is present
- Looks for a structural cause: tumour, stroke, vascular malformation, cortical dysplasia, hippocampal sclerosis
12Action EEG: Supports the Diagnosis, Never Excludes It
Routine awake EEG as soon as possible, ideally within 72 hours.
- Epileptiform abnormality raises the risk of recurrence
- Normal EEG does not exclude epilepsy
- Normal routine EEG and doubt remains: consider sleep-deprived EEG, then ambulatory EEG up to 48 hours
13Decision Any High-Risk Feature for Recurrence?
High-risk features: prior brain insult, epileptiform EEG, significant imaging abnormality, seizure in sleep, or neurological deficit.
- Overall recurrence risk is highest in the first 2 years: 21% to 45% (AAN Level A)
- Prior brain insult, such as stroke or head injury (Level A)
- EEG with epileptiform abnormalities (Level A)
- Significant brain imaging abnormality (Level B)
- Seizure during sleep (nocturnal) (Level B)
- Neurological deficit on examination (NICE)
- If Yes
14Action High-Risk Feature Present: Discuss Starting Treatment
Consider antiseizure medication (ASM) now. Decide together with the patient.
- ILAE 2014: epilepsy can be diagnosed after one unprovoked seizure if the 10-year recurrence risk is at least 60% (specialist decision)
- Immediate ASM lowers the 2-year recurrence risk by about 35% in absolute terms (AAN Level B)
- Discuss driving, work, safety and pregnancy plans
15Decision Start Antiseizure Medication Now?
Shared decision: weigh recurrence risk against side effects and patient preference.
- Immediate ASM lowers recurrence over 2 years (Level B) but may not improve quality of life (Level C)
- It does not improve long-term remission after 3 years (Level B)
- Side effects in 7% to 31%, mostly mild and reversible (Level B)
- Consider occupation, driving, pregnancy plans and patient preference
- If Yes
16Warning Before Starting ASM: Pregnancy Potential, Contraception, Valproate
Valproate: do not start in women or girls who could become pregnant unless other treatments failed or are not tolerated.
- Women who could become pregnant: pregnancy test, contraception plan, folic acid before ASM
- Men on valproate: tell them of the risk to children; contraception during and for 3 months after
- Pregnant or planning pregnancy: specialist and obstetric advice before any ASM
17Action Start ASM Now: Specialist-Led Choice
One drug at a low dose, chosen by seizure type, sex, pregnancy plans and other conditions.
- Focal seizures: lamotrigine or levetiracetam first line (NICE NG217)
- Generalised tonic-clonic: lamotrigine, levetiracetam or valproate (valproate limits above)
- Levetiracetam: watch mood, aggression and suicidal thoughts; lower dose in renal impairment
- Lamotrigine: slow titration to reduce serious rash (SJS/TEN); slower titration if on valproate; oestrogen contraceptives lower levels
- Enzyme inducers (carbamazepine, phenytoin, topiramate) reduce hormonal contraceptive effect
- Check for suicidal thoughts and mood change with any ASM
- Path rejoins step 08Shared downstream outcome
If No18Action No ASM Now: Observation
Watchful waiting with safety advice and specialist follow-up.
- Urgent review if another seizure occurs
- Review EEG and MRI results with the specialist
- Treatment can start later if risk or preference changes
- Path rejoins step 08Shared downstream outcome
If No19Action No High-Risk Feature: Observation Is Reasonable
Risk is lower, but recurrence is still possible, mostly in the first year.
- Normal EEG and MRI, no prior brain insult, normal examination
- Treatment is still an option if the person finds the risk unacceptable (NICE)
- Close specialist follow-up
- Path rejoins step 15Shared downstream outcome
If No20Action Not an Epileptic Seizure: Manage the Mimic
Find and manage the other cause. Do not start antiseizure medication.
- Abnormal ECG or features of cardiac syncope: urgent cardiac assessment (see syncope pathway)
- Suspected psychogenic non-epileptic seizure: refer to neurology for diagnosis
- Still uncertain: refer urgently to a first seizure clinic (appointment within 2 weeks)
21End Alternative Diagnosis Pathway
Continue care for the alternative diagnosis.
Guideline Source
Evidence-based guideline: Management of an unprovoked first seizure in adults - AAN/AES (Krumholz 2015; reaffirmed 10 Feb 2024), with NICE NG217 Epilepsies (2022, updated 2026)
Clinical Safety Information
Clinical Decision Support — Not a Substitute for Clinical Judgment
Individual patient factors may require deviation from these recommendations.
Known Limitations
- Adults only (16 years or older); not for children, status epilepticus or ongoing seizures
- Pregnancy over 20 weeks or postpartum is treated as eclampsia; drug choice and dosing need specialist and product information
- Driving rules differ by country and licence class; Australian rules follow Austroads
- Provoked (acute symptomatic) seizures need treatment of the cause
Contraindicated Populations
Children under 16 yearsStatus epilepticus or ongoing seizures (use status epilepticus pathway)Pregnancy over 20 weeks or postpartum (eclampsia pathway)Known epilepsy with a typical seizure
Applicable Regions
AUUSEUglobal
AU: Driving: Austroads Assessing Fitness to Drive, seizures and epilepsy chapter; the patient must tell the driver licensing authority. Emergency: call 000.
EU: ILAE 2014 practical definition of epilepsy and NICE NG217 are concordant
US: AAN/AES 2015 guideline reaffirmed 10 Feb 2024
Version 2Next review: 2027-09-30
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Related Resources
Frequently Asked Questions
What is the First Unprovoked Seizure Evaluation in Adults?
The First Unprovoked Seizure Evaluation in Adults is a diagnostic clinical algorithm for Neurology. It provides a structured decision tree to guide clinical decision-making, based on Evidence-based guideline: Management of an unprovoked first seizure in adults - AAN/AES (Krumholz 2015; reaffirmed 10 Feb 2024), with NICE NG217 Epilepsies (2022, updated 2026).
What guideline is the First Unprovoked Seizure Evaluation in Adults based on?
This algorithm is based on Evidence-based guideline: Management of an unprovoked first seizure in adults - AAN/AES (Krumholz 2015; reaffirmed 10 Feb 2024), with NICE NG217 Epilepsies (2022, updated 2026) (DOI: 10.1212/WNL.0000000000001487).
What are the limitations of the First Unprovoked Seizure Evaluation in Adults?
Known limitations include: Adults only (16 years or older); not for children, status epilepticus or ongoing seizures; Pregnancy over 20 weeks or postpartum is treated as eclampsia; drug choice and dosing need specialist and product information; Driving rules differ by country and licence class; Australian rules follow Austroads; Provoked (acute symptomatic) seizures need treatment of the cause. Individual patient factors may require deviation from these recommendations.
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