What is the recommended workup and treatment for a patient with a first-time seizure?

First-Time Seizure Workup and Management

For patients with a first-time seizure, neuroimaging of the brain should be performed in the emergency department when feasible, with laboratory testing including serum glucose and sodium levels at minimum. 1, 2

Initial Assessment and Diagnostic Workup

Laboratory Testing

• Determine serum glucose and sodium levels for all patients with first-time seizures, as these are the most common metabolic abnormalities associated with seizures 1, 3
• Obtain a pregnancy test for all women of childbearing age 1, 3
• For immunocompromised patients, perform a lumbar puncture after head CT scan 1, 3
• Consider toxicology screening if drug exposure or substance abuse is suspected 2, 3
• In patients with suspected alcohol-related seizures, check magnesium levels 3

Neuroimaging

• When feasible, perform neuroimaging of the brain in the ED on patients with a first-time seizure 1
• CT head is appropriate for emergency evaluation to rapidly identify structural pathology such as intracranial hemorrhage, stroke, or tumors 1, 2
• MRI is the preferred imaging modality for new-onset seizures when not in an emergent situation 2, 4
• Deferred outpatient neuroimaging may be considered when reliable follow-up is available 1

Electroencephalography (EEG)

• EEG is recommended as part of the neurodiagnostic evaluation of a patient with an apparent first unprovoked seizure 2, 5
• EEG helps determine the risk of recurrence and need for long-term treatment 5

Disposition Decisions

When to Activate EMS/When to Admit

• Activate EMS for first-time seizures, seizures lasting >5 minutes, multiple seizures without return to baseline between them, seizures occurring in water, seizures with traumatic injuries or difficulty breathing, seizures in pregnant individuals, or if the patient doesn't return to baseline within 5-10 minutes after seizure activity stops 1
• Consider admission if any of the following are present: persistent abnormal neurologic examination, abnormal investigation results, or if the patient has not returned to baseline 2
• Emergency physicians need not admit patients with a first unprovoked seizure who have returned to their clinical baseline in the ED 2

Risk of Recurrence

• The mean time to first seizure recurrence is 121 minutes (median 90 minutes) with more than 85% of early seizures recurring within 6 hours 2
• Nonalcoholic patients with new-onset seizures have the lowest early seizure recurrence rate (9.4%) 2

Treatment Considerations

First Aid During a Seizure

• Help the person to the ground, place them on their side in the recovery position, and clear the area around them to minimize risk of injury 1
• Stay with the person having a seizure 1
• Do not restrain the person or put anything in their mouth 1

Medication Management

• Treatment with antiepileptic medications reduces the one- to two-year risk of recurrent seizures but does not reduce the long-term risk of recurrence and does not affect remission rates 4
• If antiepileptic drugs are indicated, options include:
  • Levetiracetam: Initial dose of 500 mg twice daily, can be increased by 1000 mg/day every 2 weeks to a maximum of 3000 mg/day 6
  • Valproic acid: Initial dose of 10-15 mg/kg/day, increased by 5-10 mg/kg/week to achieve optimal clinical response, typically below 60 mg/kg/day 7

Common Pitfalls to Avoid

• Failing to identify metabolic abnormalities such as hypoglycemia or hyponatremia that may be causing the seizure 2, 3
• Missing structural lesions by not performing appropriate neuroimaging 2
• Restraining the person or putting objects in their mouth during a seizure 1
• Administering antipyretics for febrile seizures in children, as they are not effective for stopping a seizure or preventing subsequent febrile seizures 1
• Treating provoked seizures with antiepileptic drugs when only relief of the provoking factor is needed 8

Special Considerations

• Lumbar puncture should be performed when there is concern about possible meningitis or encephalitis 2, 9
• Immunocompromised patients require more extensive evaluation, including lumbar puncture, due to higher rates of CNS infections presenting with seizures 1, 3
• A seizure diagnosis severely limits a patient's driving privileges, although laws vary by state 4