New-Onset Seizure

complete reference · provoked vs unprovoked · workup · when to start an AED · driving counseling · Full Card

Symptoms / Associated Sx

• A witnessed generalized tonic-clonic event with rhythmic synchronous jerking, lateral tongue-biting, urinary incontinence, and a clear post-ictal period (confusion, somnolence, gradual reorientation over minutes-to-an-hour) is highly suggestive. Focal-onset features (déjà vu, rising epigastric sensation, automatisms, unilateral jerking) localize the focus; a transient post-ictal focal weakness is Todd paralysis. An aura before the event and the slow post-ictal recovery best separate seizure from syncope.

Neg

• Pt denies abrupt loss of consciousness with near-immediate full recovery and no post-ictal confusion — argues against syncope (convulsive syncope can have brief myoclonic jerks but lacks a true post-ictal state; look for a cardiac/vasovagal trigger)

• No clear emotional/situational trigger with asynchronous, side-to-side, waxing-waning movements and closed eyes — argues against psychogenic non-epileptic seizure (PNES: preserved awareness, pelvic thrusting, eye closure with resistance, normal ictal EEG — but PNES and epilepsy can coexist)

• Awareness was lost (not retained) during the motor activity — argues against a movement disorder, rigors, or tremor (those preserve consciousness)

Social History (SHx)

• Alcohol use and the timing of last drink (withdrawal seizures at 6–48h); recreational/illicit drugs and stimulant use or sedative withdrawal; sleep deprivation; AED non-adherence in known epilepsy.

• Prior head trauma, CNS infection, stroke, or birth/developmental history; family history of epilepsy; pregnancy (eclampsia).

Main Etiology

• Provoked (acute symptomatic) — a transient cause: hypo- or hyperglycemia, hyponatremia, hypocalcemia, hypomagnesemia, alcohol or benzodiazepine/barbiturate withdrawal, drug toxicity (cocaine, sympathomimetics, bupropion, tramadol), CNS infection, head trauma, eclampsia, uremia/hepatic failure, hypertensive encephalopathy/PRES.

• Unprovoked: structural lesion (brain tumor, prior stroke or trauma, cortical malformation, mesial temporal sclerosis) or a genetic/idiopathic epilepsy syndrome. New focal seizures in an adult demand structural imaging to exclude a mass.

RF

• Modifiable: alcohol/drug use and withdrawal, sleep deprivation, medication non-adherence, proconvulsant drugs.

• Non-modifiable: prior brain injury/stroke, structural lesions, family history/genetic epilepsy.

Data

• POC glucose and electrolytes — sodium, calcium, magnesium (the reversible metabolic provokers; check and correct first)

• CBC, BUN/Cr, LFTs, urine and serum toxicology, β-hCG (uremia, hepatic failure, intoxication/withdrawal, eclampsia)

• Neuroimaging — non-contrast CT acutely to exclude hemorrhage/mass, then MRI brain (superior for tumors, cortical dysplasia, mesial temporal sclerosis, old infarct — the structural yield)

• EEG (epileptiform discharges raise recurrence risk and support starting an AED; also detects non-convulsive status if the patient isn't waking up)

• Lumbar puncture if fever, immunocompromise, or persistent altered mental status (CNS infection — after imaging)

• Prolactin (limited use), ECG (distinguish convulsive syncope/arrhythmia — long QT, Brugada)

DDx

Syncope (including convulsive) (brief, rapid recovery, cardiac/vasovagal trigger, no true post-ictal state) · psychogenic non-epileptic seizure (situational, asynchronous movements, eye closure, normal ictal EEG) · TIA (negative/loss symptoms, no LOC) · migraine with aura (positive marching visual symptoms, headache) · movement disorder / rigors (awareness retained) · metabolic encephalopathy with myoclonus (diffuse, underlying derangement)

Home Meds

• Reconcile any anticonvulsant (and check levels — a "new" seizure may be subtherapeutic levels in known epilepsy).

• Review and adjust proconvulsant drugs (bupropion, tramadol, certain antibiotics, theophylline) where feasible.

• Correct contributors — antihyperglycemics causing hypoglycemia, drugs causing hyponatremia.

Plan

Consults

• Neurology — classification, EEG/MRI interpretation, AED decision and long-term plan.

• Neurosurgery — if a resectable structural lesion is found.

• ICU — for status epilepticus, airway compromise, or non-convulsive status on EEG; OB if eclampsia suspected.

Correct provokers

• Treat reversible causes immediately: dextrose (D50) for hypoglycemia (give thiamine 100–500 mg IV first if alcohol/malnutrition possible), hypertonic saline cautiously for symptomatic hyponatremia, IV calcium and magnesium for deficiencies, treat infection, manage eclampsia with magnesium. A purely provoked seizure usually does not require long-term AED — fix the cause.

AED decision (first unprovoked)

• Start an AED after a single unprovoked seizure only when recurrence risk is high — epileptiform abnormality on EEG, a structural lesion on imaging, an abnormal neuro exam, or a nocturnal seizure (these roughly double the ~2-year recurrence risk; AHS/AAN guidance). Otherwise it is reasonable to defer and treat after a second seizure.

• First-line options: levetiracetam (Keppra) 500–1000 mg PO BID (titrate; watch for irritability/mood effects), or lamotrigine (Lamictal, slow titration), or lacosamide (Vimpat). Choose by comorbidity, interactions, and (in people who can become pregnant) teratogenicity — avoid valproate (Depakote) where pregnancy is possible.

Acute / recurrent seizure

• If actively seizing or recurring: lorazepam (Ativan) 4 mg IV (repeat once) for abortive control, then a loading AED — levetiracetam (Keppra) 60 mg/kg IV, fosphenytoin (Cerebyx) 20 mg PE/kg, or valproate (Depacon) 40 mg/kg (see status epilepticus card for the full algorithm).

Always

• PT / OT eval if injury from the event or functional concern.

• Trend: resolution of post-ictal confusion (persistent altered mental status → EEG for non-convulsive status); EEG and MRI results; AED level if started; electrolytes/glucose.

• Escalation triggers: seizure ≥5 minutes or recurrent without recovery → status epilepticus pathway, ICU · failure to return to baseline → EEG to exclude NCSE, ICU · airway compromise → intubate.

• Discharge checklist: AED with dose/titration plan if started (and level monitoring) · driving restriction counseling per state law (document) · safety precautions — no swimming/bathing alone, avoid heights/operating dangerous machinery, sleep hygiene, alcohol avoidance · neurology follow-up with outpatient EEG/MRI if not completed · seizure first-aid education for family · return precautions (recurrent or prolonged seizure → 911).

Red Flags — ICU / Urgent

• Status epilepticus (≥5 min continuous, or repeated seizures without recovery) → benzodiazepine + loading AED, ICU.
• Failure to wake up post-ictally → non-convulsive status epilepticus until EEG proves otherwise.
• Fever + seizure + altered mental status → CNS infection; LP and empiric antimicrobials/acyclovir.
• Focal new-onset seizure in an adult → image for a mass; new structural lesion needs urgent workup.
• Pregnant with seizure + hypertension → eclampsia; magnesium, urgent OB.

Senior IM Resident Pearls

• The first question is provoked or unprovoked. A seizure caused by hypoglycemia, hyponatremia, or withdrawal is treated by fixing the cause — it is not epilepsy and usually needs no chronic AED. Don't commit someone to lifelong medication for a metabolic event.
• Check the sugar and the sodium before anything fancy. The highest-yield, most reversible causes are metabolic and at the bedside in minutes.
• Thiamine before glucose in anyone who might be alcohol-dependent or malnourished — a dextrose bolus can precipitate Wernicke.
• Start an AED after a first unprovoked seizure only if recurrence risk is high: epileptiform EEG, structural lesion, abnormal exam, or nocturnal onset. Absent those, deferring is guideline-supported and avoids overtreatment.
• If they don't wake up, get an EEG. Non-convulsive status epilepticus is a classic miss in the "slow to recover" post-ictal patient.
• A new focal seizure in an adult is a brain tumor until imaged. Don't anchor on alcohol — get the MRI.
• Driving counseling is not optional. Document the restriction per your state's law at discharge; it's a medicolegal and safety issue.
• Common mistake: calling every shaking spell a seizure. Convulsive syncope and PNES are common mimics — the history (trigger, recovery speed, post-ictal state) and EEG sort them out.