Seizure (first, single, or provoked)
A first or provoked seizure requires a focused history to distinguish it from syncope or a nonepileptic event, urgent glucose and electrolyte testing, brain MRI, and outpatient EEG; an unprovoked seizure with normal imaging and EEG usually does not require antiepileptic drug therapy, since epilepsy is defined only after a second unprovoked seizure or a high-risk first one.
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What this article covers
- Overview
Definition: a seizure is a single paroxysmal episode of abnormal, excessive neuronal electrical activity producing a transient change in behavior, movement, sensation, or awareness; this article…
- Epidemiology
Common presentation: a first seizure is a frequent acute neurologic presentation across all ages, with a bimodal peak in early childhood and older adults.
- Risk factors
Family history of seizures, especially in a first-degree relative, raises the likelihood of recurrence.
- Pathophysiology
Hypersynchronous neuronal discharge: a seizure results from excessive, synchronous electrical discharge in cortical neurons, arising focally or, in generalized-onset seizures, across both hemispheres simultaneously.
- Clinical features
Positive ictal symptoms: jerking, clonic movements, tonic stiffening, automatisms (lip smacking, hand fumbling), and positive sensory phenomena (tingling, visual flashes) suggest a seizure, unlike…
- Differential diagnosis
Epilepsy: distinguished by prior similar unprovoked episodes, or a current event meeting the recurrence-risk threshold that defines epilepsy after only one seizure; managed with chronic drug therapy, not the observation-first approach here.
- Diagnosis
First, establish that the event was a seizure by history: a detailed history from the patient and witnesses distinguishes a true seizure from syncope, a psychogenic event, or another mimic before further workup.
- Management
First, treat any identified provoking cause directly: for hypoglycemia give dextrose 50% (D50W) 25 g IV push once, repeated if glucose remains below 70 mg/dL; correct other electrolytes, taper for…
- Complications
Injury during the seizure: falls, fractures, tongue or oral trauma, and burns, particularly during a hazardous activity.
- Prognosis
Provoked seizures generally have a good prognosis once the cause is corrected, with a low risk of future unprovoked seizures absent an epilepsy risk factor.
- Prevention
Correct and avoid known provoking factors: treat metabolic derangements, avoid or taper medications that lower the seizure threshold, moderate alcohol intake, and maintain adequate sleep.
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Epilepsy is a disease of recurrent unprovoked seizures, defined as two unprovoked seizures more than 24 hours apart or one unprovoked seizure with at least a 60% recurrence risk; treatment is guided by seizure type, with levetiracetam or lamotrigine preferred first-line for most adults.
- Status epilepticus
Status epilepticus is a generalized tonic-clonic seizure lasting more than 5 minutes, or repeated seizures without return to baseline, and is a neurologic emergency. Treatment is a timed escalation: IV benzodiazepine first, then an IV antiepileptic drug, then anesthetic coma with continuous EEG if convulsions persist.
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Functional seizures (psychogenic nonepileptic seizures/events, PNES) are paroxysmal episodes resembling epileptic seizures but caused by a functional disturbance of the nervous system rather than abnormal cortical electrical discharge. Diagnosis requires video-EEG capturing a typical event with no ictal correlate; management is multidisciplinary, centered on diagnosis disclosure and psychotherapy, not antiseizure drugs.
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