Review Question - QID 217314

This patient presents with an unprovoked, generalized, tonic-clonic seizure (loss of consciousness, extremity convulsions) and is currently back at her neurological baseline. After laboratory studies and urine toxicology studies are sent, the most appropriate next step in management is obtaining head imaging (e.g., MRI) to rule out structural etiologies.

The work-up of a first seizure includes a detailed history of the seizure event as well as medical, family, and social histories to identify seizure characteristics and/or triggers. Triggers include trauma, fever, drugs, stress, intense exercise, and/or intense sensory phenomena (e.g., loud music, flashing lights). A neurological exam should be performed to rule out organic causes such as central nervous system infection or hemorrhage, but is typically unremarkable in epileptic seizures. A rapid point-of-care glucose measurement should be performed and other laboratory studies sent, including electrolytes, complete blood count, renal/liver function tests, and urine toxicology screen. An electrocardiogram should be performed in all patients with loss of consciousness to rule out cardiogenic etiologies. Then, neuroimaging should be performed to rule out structural brain causes. MRI is preferred over computed tomography (CT) scans because of its greater sensitivity. For patients who have returned to their baseline, an EEG can be performed on an outpatient basis. For patients with findings concerning for meningitis and/or encephalitis (e.g., fever, possible infectious source), a lumbar puncture should be done. For patients with a concern for head trauma, a CT scan should be done before MRI to rule out acute hemorrhage.

Jimenez-Villegas et al. reviewed the diagnosis and management of a first unprovoked seizure in pediatric and adult populations. They discuss how some unprovoked seizures may be due to structural brain lesions. They recommend neuroimaging to identify potentially epileptogenic brain lesions in patients with a first unprovoked seizure in order to allow for appropriate management.

Incorrect Answers:
Answer 1: Administration of lorazepam would be appropriate for patients who are actively seizing or who are in status epilepticus, defined as >=5 minutes of continuous seizure or >=2 seizures with incomplete recovery of consciousness in between. This patient is back to her neurological baseline; further work-up should focus on elucidating potential causes.

Answer 2: Electroencephalogram (EEG) would be appropriate for further work-up in this patient but since she is back to neurological baseline, it can be done on an outpatient basis (lower urgency). Neuroimaging takes precedence to rule out structural etiologies. EEG would be a higher priority if there is a concern for status epilepticus where the patient does not return to neurologic baseline.

Answer 3: Lumbar puncture would be appropriate if this patient demonstrated signs of central nervous system infection. For example, fever, neck pain, and/or nuchal rigidity is suggestive of meningitis, which requires a lumbar puncture. In the absence of infectious symptoms, a lumbar puncture would be lower yield.

Answer 4: Magnetic resonance angiography is commonly used to evaluate intracranial vascular pathology in the setting of stroke. It is not typically used in the work-up of unprovoked seizures, in which an MRI provides more direct information about brain structure.

Bullet Summary:
In patients with a first, unprovoked seizure, neuroimaging (e.g., MRI or CT) should be performed after initial laboratory and urine toxicology studies are sent to identify structural brain lesions.