A 23-year-old man is brought to the emergency department by ambulance due to a seizure. According to a witness, the patient fell on the sidewalk while leaving a pub and had rhythmic movements of the extremities for about 2 minutes. He has no history of seizures. In the emergency department, the patient is lethargic and confused but follows simple commands. Temperature is 37.3 C (99.1 F), blood pressure is 122/70 mm Hg, and pulse is 97/min. The pupils are equal and reactive to light. He moves all extremities, and deep tendon reflexes are symmetric. Complete blood count, serum electrolytes, and ECG are normal. A urine toxicology screen is ordered. What is the most appropriate next step in management of this patient?
First-time seizure in adults | |
Etiology |
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Evaluation |
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Indication to start antiepileptic medications |
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EEG = electroencephalography. | |
This patient has had a first-time seizure. Neuroimaging with CT scan or MRI should be performed in patients with a first-time seizure as part of the neurodiagnostic evaluation; the choice of modality depends on the clinical presentation.
CT scan of the head without contrast can rapidly identify acute life-threatening neurologic conditions (eg, epidural or intracranial bleed) that could cause seizure and require urgent intervention. Given this patient's continued altered mental status (lethargic and confused) and recent head trauma (fall) possibly in the setting of heavy alcohol use (leaving a pub), CT scan of the head without contrast is indicated. Other findings that could indicate an acute intracranial process include focal seizure, focal neurologic deficits, or anticoagulation therapy.
In nonemergency or elective situations, MRI is the modality of choice. It is more time-consuming but more sensitive than CT scan in identifying most structural causes of epilepsy (eg, temporal sclerosis, cortical dysplasia, vascular malformations, tumors).
(Choice A) An acute bleed or a large structural abnormality can be identified on a CT scan of the head without contrast. After these are excluded, further neuroimaging would be needed to evaluate for smaller lesions that may be a focus for seizure activity. Compared to MRI of the brain, a CT scan with contrast provides limited information on a structural abnormality or mass lesion and is not routinely obtained in seizure evaluation.
(Choice C) Electroencephalography (EEG) is useful in patients with unprovoked first-time seizure. It helps to stratify patient risk to determine if antiepileptic agents are needed. However, in a patient with a recent fall and continued altered mental status, it is important to rule out brain lesions (eg, intracranial bleeding) with neuroimaging prior to EEG.
(Choice D) Intravenous phenytoin infusion is useful for patients with active seizure or concern for status epilepticus. These are unlikely in this patient who is moving all extremities and following simple commands.
(Choice E) A lumbar puncture should be performed if the patient exhibits manifestations suggestive of acute CNS infection (eg, fever, nuchal rigidity, focal signs). Moreover, a lumbar puncture should be performed only after a space-occupying lesion has been excluded by neuroimaging studies.
Educational objective:
CT scan of the head without contrast is the initial imaging study of choice in patients with first-time seizure to exclude acute neurologic conditions (eg, intracranial or epidural bleed) that might require urgent intervention. MRI is more sensitive than CT scan in identifying most structural causes of epilepsy and is the neuroimaging modality of choice in elective situations.