What is the most appropriate next step in managing a new-onset seizure in a patient with no significant medical history or history of seizure disorder or epilepsy?

Management of New-Onset Seizure in an Adult

Obtain a non-contrast head CT immediately to rule out structural pathology requiring urgent intervention, then discharge home with neurology follow-up if the patient has returned to baseline, has a normal neurological examination, and no high-risk features are present. 1

Initial Imaging Decision

In the emergency department setting with a patient who has returned to baseline mental status and has no focal neurological deficits, non-contrast head CT is the appropriate initial imaging study to rapidly identify structural pathology such as intracranial hemorrhage, stroke, vascular malformation, hydrocephalus, or tumors that may require immediate neurosurgical intervention. 2, 1

• CT is preferred in the acute setting because it can be performed quickly without extensive safety screening and allows ready access to the patient during scanning. 2
• While MRI is superior for detecting epileptogenic lesions (70-80% sensitivity vs. 30% for CT), it is the preferred study for non-emergent evaluation and can be arranged as outpatient follow-up. 2, 1, 3

Laboratory Evaluation

Check serum glucose and sodium levels immediately, as these are the most frequent metabolic abnormalities identified in patients with new-onset seizures and are the only laboratory values that consistently alter acute management. 1

• Additional laboratory tests (CBC, comprehensive metabolic panel) should only be obtained if suggested by specific clinical findings such as vomiting, diarrhea, or dehydration. 1
• Consider toxicology screening if there is any suspicion of drug exposure or substance abuse. 1

Disposition Decision

This patient does NOT require admission based on the clinical presentation described. 1

• The American College of Emergency Physicians recommends that emergency physicians need not admit patients with a first unprovoked seizure who have returned to their clinical baseline in the ED. 1
• Admission should be considered only if: persistent abnormal neurological examination, abnormal investigation results requiring inpatient management, or the patient has not returned to baseline. 1

Why NOT Start Antiepileptic Drugs Now

Do not initiate levetiracetam or other antiepileptic drugs in the emergency department for a single first-time seizure. 1

• Antiepileptic drug treatment reduces 1-2 year recurrence risk but does not affect long-term recurrence rates or remission rates. 1
• Starting treatment for a single seizure exposes patients to medication adverse effects without proven mortality or morbidity benefit. 1
• The recurrence risk for nonalcoholic patients with new-onset seizures is only 9.4% in the early period. 1
• The decision to start antiepileptic therapy should be made by neurology after outpatient evaluation including EEG and potentially MRI. 1

Why NOT Prescribe Lorazepam "As Needed"

Do not provide a prescription for lorazepam or other benzodiazepines for home use "as needed."

• Benzodiazepines are first-line therapy for status epilepticus (prolonged or repetitive seizures), not for isolated seizures. 1
• Most seizures are self-limited and terminate spontaneously within 2-3 minutes. 4
• If a second seizure occurs, the patient should activate emergency medical services rather than self-administer medication.
• The mean time to first seizure recurrence is 121 minutes (median 90 minutes), with more than 85% of early recurrences happening within 6 hours—meaning if recurrence occurs, it will likely happen before the patient could safely leave the ED. 1

Appropriate Discharge Plan

Discharge with the following plan:

• Arrange outpatient neurology follow-up within 1-2 weeks. 1
• Outpatient MRI brain without contrast (preferred over CT for detecting epileptogenic lesions). 2, 1, 3
• Outpatient EEG as part of the neurodiagnostic evaluation. 1
• Provide seizure precautions: no driving per state law (typically 3-6 months seizure-free required), avoid heights, swimming alone, or operating dangerous machinery. 4
• Educate that the decision to start antiepileptic medication will be made by neurology based on recurrence risk factors including EEG findings, MRI results, and clinical features. 1

Common Pitfalls to Avoid

• Failing to obtain CT in the acute setting: Even though this patient has returned to baseline, CT is needed to exclude structural lesions requiring intervention. 1
• Starting antiepileptic drugs prematurely: This exposes patients to medication side effects without proven benefit for a single seizure. 1
• Assuming normal CT excludes all pathology: MRI may still reveal significant epileptogenic lesions in 22% of patients with normal neurologic examinations. 1, 5
• Admitting unnecessarily: Admission is not indicated for patients who have returned to baseline with normal examination and no concerning features. 1