What diagnostic studies are indicated for a patient with a history of seizures presenting to the Emergency Department (ED) with recurrent seizures?

From the Guidelines

For a patient presenting to the emergency department with recurrent seizures and a history of seizures, I would order a comprehensive diagnostic workup, prioritizing tests that can quickly identify potentially life-threatening causes of seizure recurrence, such as acute intracranial pathology or metabolic derangements, as recommended by the most recent clinical policy from the American College of Emergency Physicians (ACEP) 1.

Initial Evaluation

Initially, I would obtain basic laboratory studies including:

• Complete blood count
• Comprehensive metabolic panel (with glucose, sodium, calcium, magnesium levels)
• Anticonvulsant drug levels if the patient is on medication therapy Toxicology screening should be performed to identify potential substance use.

Neuroimaging and Electroencephalogram

An electroencephalogram (EEG) is essential to evaluate for seizure activity and epileptiform discharges. Brain imaging with CT scan should be done immediately to rule out acute intracranial pathology, followed by MRI if available as it provides better visualization of structural abnormalities like hippocampal sclerosis, cortical dysplasia, or tumors, as suggested by previous studies 1.

Additional Tests

Lumbar puncture may be necessary if meningitis or encephalitis is suspected, particularly if the patient has fever or altered mental status. These tests help identify the cause of seizure recurrence, which could include medication non-compliance, metabolic derangements, structural brain changes, infection, or progression of underlying epilepsy.

Importance of Prompt Evaluation

Addressing these factors promptly is crucial for seizure control and preventing status epilepticus, which carries significant morbidity and mortality risks, highlighting the need for a comprehensive and timely diagnostic workup in the emergency department setting, as emphasized by the latest clinical policy 1.

From the Research

Diagnostic Studies for Recurrent Seizures

The following diagnostic studies can be ordered for a patient with a history of seizures presenting to the emergency department (ED) with recently recurrent seizures:

• Electroencephalography (EEG) to evaluate seizure activity and determine the type of seizure 2, 3
• Neuroimaging, such as magnetic resonance imaging (MRI) or computed tomography (CT), to identify any structural brain abnormalities or lesions that may be causing the seizures 2, 4
• Laboratory tests, including:
  • Sodium and glucose levels to check for any electrolyte imbalances or metabolic disorders that may be contributing to the seizures 2
  • Prolactin testing to help differentiate between epileptic and non-epileptic seizures 5
  • Creatine kinase (CK) levels to check for any muscle damage or rhabdomyolysis that may have occurred during the seizure 5
  • Metabolic markers, such as ammonia and lactate, to check for any underlying metabolic disorders that may be contributing to the seizures 5
  • Electrolytes, creatinine, liver, and renal function tests to check for any underlying conditions that may be contributing to the seizures 5

Indications for Diagnostic Studies

The decision to order diagnostic studies should be based on the patient's clinical presentation and history. The following factors may indicate the need for diagnostic studies:

• Acute head trauma 4
• Prolonged alteration of consciousness 4
• Focal neurologic examination at presentation 4
• History of malignancy or other underlying medical conditions that may be contributing to the seizures 2, 6
• Unknown cause of seizures or new-onset seizures 2, 6