Seizure
A streamlined, differential-led presentation for rapid clinical review.
Twenty-second review
- Seizures result from abnormal synchronous cortical activity and may be provoked by structural, metabolic, toxic, infectious, withdrawal, or epilepsy-related causes.
- Ongoing seizure, repeated seizure without recovery, pregnancy, trauma, fever with meningism, focal deficit, or prolonged altered state requires urgent escalation.
- Keep syncope or psychogenic nonepileptic event in the differential; overlapping or concurrent illness remains possible.
- For seizure, trends and combinations of findings are more informative than one isolated vital sign.
Compare the clinical patterns
The repeated material is grouped inside each possibility. Open only the condition you need.
Status epilepticusTime-sensitive high-risk possibility
HPI
Clarify first seizure or known disorder; witnessed; duration.
Signs & symptoms
Persistent activity, no recovery, focal deficit, fever, or severe headache.
Focused exam
Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.
Brief pathophysiology
Status epilepticus may cause seizure through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.
Heart rate (bpm)
Often rises transientlyAutonomic activation commonly causes postictal tachycardia.
Oxygen saturation (SpO₂)
May fall transientlyApnea, obstruction, or hypoventilation can lower saturation.
Blood glucose (mmol/L)
Check earlyHypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.
Temperature (°C)
May riseA brief rise may follow seizure; fever raises concern for infection or a provoking illness.
Front-load in the triage report
- Status epilepticus: Persistent activity, no recovery, focal deficit, fever, or severe headache.
- First seizure or known disorder?
- Witnessed?
Intracranial eventTime-sensitive high-risk possibility
HPI
Clarify witnessed; duration; generalized vs focal.
Signs & symptoms
Persistent activity, no recovery, focal deficit, fever, or severe headache.
Focused exam
Compare findings with baseline and collateral history; Protect from injury; assess E/V/M recovery, pupils, focal findings, tongue injury, incontinence, trauma, temperature, and medication adherence.
Brief pathophysiology
Intracranial event may cause seizure through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.
Heart rate (bpm)
Often rises transientlyAutonomic activation commonly causes postictal tachycardia.
Oxygen saturation (SpO₂)
May fall transientlyApnea, obstruction, or hypoventilation can lower saturation.
Blood glucose (mmol/L)
Check earlyHypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.
Temperature (°C)
May riseA brief rise may follow seizure; fever raises concern for infection or a provoking illness.
Front-load in the triage report
- Intracranial event: Persistent activity, no recovery, focal deficit, fever, or severe headache.
- Witnessed?
- Duration?
CNS infectionTime-sensitive high-risk possibility
HPI
Clarify duration; generalized vs focal; multiple seizures.
Signs & symptoms
Persistent activity, no recovery, focal deficit, fever, or severe headache.
Focused exam
Compare findings with baseline and collateral history; Protect from injury; assess E/V/M recovery, pupils, focal findings, tongue injury, incontinence, trauma, temperature, and medication adherence.
Brief pathophysiology
CNS infection may cause seizure through a time-sensitive process capable of rapid physiological deterioration.
What the trend may show
CNS infection may produce fever and systemic illness, but classic findings and abnormal vitals can be absent. Altered mental status, rash, shock, or seizures increase urgency.
Temperature (°C)
Often elevatedFever supports infection; normal temperature does not exclude it.
Heart rate (bpm)
May riseTachycardia may reflect fever, pain, or sepsis.
Blood pressure (mmHg)
May fall with sepsisHypotension suggests systemic involvement or shock.
Blood glucose (mmol/L)
Check earlyGlucose disturbance is an important reversible mimic of altered mentation or seizure.
Front-load in the triage report
- CNS infection: Persistent activity, no recovery, focal deficit, fever, or severe headache.
- Duration?
- Generalized vs focal?
Known epilepsy with breakthrough seizureCommon presentation pattern
HPI
Clarify first seizure or known disorder; witnessed; duration.
Signs & symptoms
Missed medication, sleep loss, illness, or substance use may lower threshold.
Focused exam
Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.
Brief pathophysiology
Known epilepsy with breakthrough seizure may explain the presenting symptoms through a common clinical mechanism, while serial assessment checks for complications or an alternate cause.
What the trend may show
Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.
Heart rate (bpm)
Often rises transientlyAutonomic activation commonly causes postictal tachycardia.
Oxygen saturation (SpO₂)
May fall transientlyApnea, obstruction, or hypoventilation can lower saturation.
Blood glucose (mmol/L)
Check earlyHypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.
Temperature (°C)
May riseA brief rise may follow seizure; fever raises concern for infection or a provoking illness.
Front-load in the triage report
- Missed medication, sleep loss, illness, or substance use may lower threshold.
- First seizure or known disorder?
- Witnessed?
SyncopeImportant alternative presentation
HPI
Clarify first seizure or known disorder; witnessed; duration.
Signs & symptoms
Event description and recovery pattern help, but avoid certainty from one feature.
Focused exam
Record GCS components, pupils, speech, gaze, motor symmetry, sensation, coordination, and gait when safe; Compare findings with baseline and collateral history.
Brief pathophysiology
Syncope can resemble seizure through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.
Heart rate (bpm)
Often rises transientlyAutonomic activation commonly causes postictal tachycardia.
Oxygen saturation (SpO₂)
May fall transientlyApnea, obstruction, or hypoventilation can lower saturation.
Blood glucose (mmol/L)
Check earlyHypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.
Temperature (°C)
May riseA brief rise may follow seizure; fever raises concern for infection or a provoking illness.
Front-load in the triage report
- Event description and recovery pattern help, but avoid certainty from one feature.
- First seizure or known disorder?
- Witnessed?
Psychogenic nonepileptic eventImportant alternative presentation
HPI
Clarify witnessed; duration; generalized vs focal.
Signs & symptoms
Event description and recovery pattern help, but avoid certainty from one feature.
Focused exam
Compare findings with baseline and collateral history; Protect from injury; assess E/V/M recovery, pupils, focal findings, tongue injury, incontinence, trauma, temperature, and medication adherence.
Brief pathophysiology
Psychogenic nonepileptic event can resemble seizure through overlapping symptoms or referred physiology despite a different primary mechanism.
What the trend may show
Transient tachycardia and hypoxemia can follow a generalized seizure. Persistent abnormality, fever, recurrent activity, or failure to recover should prompt a search for the cause and complications.
Heart rate (bpm)
Often rises transientlyAutonomic activation commonly causes postictal tachycardia.
Oxygen saturation (SpO₂)
May fall transientlyApnea, obstruction, or hypoventilation can lower saturation.
Blood glucose (mmol/L)
Check earlyHypoglycemia can provoke or mimic seizure; hyperglycemia may be a stress response.
Temperature (°C)
May riseA brief rise may follow seizure; fever raises concern for infection or a provoking illness.
Front-load in the triage report
- Event description and recovery pattern help, but avoid certainty from one feature.
- Witnessed?
- Duration?
Findings that should escalate concern
- Ongoing seizure, repeated seizure without recovery, pregnancy, trauma, fever with meningism, focal deficit, or prolonged altered state requires urgent escalation.
- Status epilepticus, intracranial event, or CNS infection: Persistent activity, no recovery, focal deficit, fever, or severe headache.
Medication recognition
Continue the clinical pathway
Clinical and academic sources
Curated clinical guidance and peer-reviewed evidence supporting this presentation. Current BCEHS guidance, medical direction, and local policy remain authoritative for practice.
BCEHS Handbook — specific CPGs
Supporting clinical and academic evidence
- CEDIS Presenting Complaint List updateCanadian Association of Emergency Physicians
Presenting-complaint terminology and categorization context. It does not establish a prehospital “top 100” ranking.
- WHO Medical Emergency ChecklistWorld Health Organization
A structured emergency assessment framework intended to reduce missed life-threatening conditions.
- Emergency management of epileptic seizures: a consensus statementEmergencias · 2020
Emergency seizure assessment, reversible causes, status epilepticus recognition, and initial management.