What is the initial workup for a patient presenting with a possible seizure?

Initial Workup for a Patient Presenting with a Possible Seizure

The initial workup for a patient presenting with a possible seizure should include neuroimaging of the brain, basic laboratory tests, and an electroencephalogram (EEG), with brain imaging being particularly important for first-time seizures. 1

Immediate Assessment

• Assess vital signs and ensure patient safety with attention to airway, breathing, and circulation 1
• Maintain NPO status until swallowing assessment is completed to prevent aspiration, especially in patients who have had multiple seizures 2
• Evaluate Glasgow Coma Scale (GCS) score, as a GCS <15 is associated with higher risk of early seizure recurrence 1
• Document time of seizure onset, duration, and characteristics (focal vs. generalized, motor activity, post-ictal state) 1

Laboratory Studies

• Obtain basic metabolic panel to identify common metabolic causes of seizures:
  • Serum glucose (both hypoglycemia and hyperglycemia can trigger seizures) 3
  • Serum sodium (hyponatremia is a common cause of provoked seizures) 4
  • Calcium and magnesium levels (abnormalities may lower seizure threshold) 3
  • BUN and creatinine (renal dysfunction may affect seizure threshold) 4
• Check antiepileptic drug levels in patients on these medications 3
• Consider toxicology screening if substance use is suspected 4

Neuroimaging

• Perform neuroimaging of the brain in the ED for patients with a first-time seizure (Level B recommendation) 1
• MRI is preferred over CT except when acute intracranial bleeding is suspected 5
• Urgent neuroimaging is particularly indicated when:
  • History of acute head trauma 1
  • History of malignancy or immunocompromise 1
  • Persistent headache 1
  • Anticoagulation therapy 1
  • New focal neurologic deficits 1
  • Age older than 40 years 1
  • Focal seizure onset before generalization 1
  • Fever (suggesting possible CNS infection) 1

Electroencephalography (EEG)

• EEG is recommended for all patients presenting with a first seizure 5
• EEG can help differentiate seizure from non-seizure events and identify epileptiform abnormalities 6
• Consider emergent EEG if non-convulsive status epilepticus is suspected in patients with persistent altered mental status 4

Risk Assessment for Seizure Recurrence

• Early seizure recurrence is common, with mean time to first recurrence of 121 minutes (median 90 minutes) 1
• Risk factors for early seizure recurrence include:
  • Age ≥40 years 1
  • Alcoholism (alcoholic patients with history of seizures have highest recurrence rate at 25.2%) 1
  • Hyperglycemia 1
  • GCS score <15 1
  • History of CNS injury (stroke, trauma, tumor) 1

Disposition Decision-Making

• Patients with a first unprovoked seizure who have returned to clinical baseline may not require admission (Level C recommendation) 1
• Consider admission for:
  • Patients with abnormal neuroimaging findings 1
  • Patients with persistent neurologic deficits 1
  • Patients with provoked seizures where the underlying cause requires treatment 1
  • Patients with high risk of early recurrence (alcoholics, abnormal GCS) 1
• Deferred outpatient neuroimaging may be used when reliable follow-up is available (Level B recommendation) 1

Common Pitfalls to Avoid

• Failing to identify and treat underlying medical causes of seizures, such as electrolyte abnormalities, hypoglycemia, or drug toxicity 4
• Allowing oral intake too early before proper swallowing assessment, which can lead to aspiration pneumonia 2
• Overlooking non-convulsive status epilepticus in patients with persistent altered mental status 4
• Initiating long-term antiepileptic medications in the ED for patients with a first unprovoked seizure without evidence of brain disease or injury (Level C recommendation) 1
• Discharging patients without appropriate driving precautions and follow-up arrangements 5