• Critical Care
• Neuroimaging

• Critical Care
• Neuroimaging
• Emergency Medicine

Up to 5% of individuals in the United States will experience a nonfebrile seizure during their lifetime. Yet, the accurate diagnosis of seizure can be challenging for emergency department (ED) physicians. Jordan Bonomo, MD, University of Cincinnati Medical Center, Cincinnati, Ohio, USA, discussed the American College of Emergency Physicians' (ACEP) 2014 update regarding the evaluation and management of adult patients presenting to the ED with seizures [Huff JS et al. Ann Emerg Med. 2014].

In this update of the 2004 clinical policy, seizure definitions were modified. For example, status epilepticus (SE) was defined as clinical or electroencephalographic (EEG) seizure activity for > 5 minutes, continuously or recurrently, without full recovery between events. SE is categorized as convulsive, nonconvulsive, or refractory. Dr Bonomo pointed out that most seizures do not meet these criteria because seizure activity lasts < 5 minutes.

The 2014 policy provides level B recommendations that all patients presenting with seizure should be evaluated with blood glucose and sodium levels. In addition, all women should be tested for pregnancy, and immunocompromised patients should undergo lumbar puncture. Although the policy does not provide level A recommendations regarding the use of computed tomography (CT) imaging, cranial CT imaging should be performed on all patients who present with their first-ever seizure. In addition, neurologic experts recommend that magnetic resonance imaging (MRI) should be conducted on first seizure presentation, because up to 15% of patients with a normal CT will demonstrate a suspect lesion on MRI.

Because up to 15% of patients with acute ischemic stroke (AIS) will present with seizure at the onset of the AIS, it is important to determine if a witnessed seizure is an AIS mimic. The only protocol that can accurately screen for AIS is MRI with diffusion-weighted imaging (DWI). In one study, DWI-only MRI was rapid, and the odds ratio of positive DWI findings in patients with > 1 symptoms was 9.4 (95% CI, 3.8 to 23.5) [Eichel R et al. J Neurol Sci. 2013]. There were no false positives related to seizure reported. The purpose of MRI imaging in patients presenting with seizure is to identify the underlying source of the seizure, such as a malignancy, vascular pathology, or structural issues.

When a patient presents with seizure, it is important that pharmacologic control is achieved [Huff JS et al. Ann Emerg Med. 2014]. The speed of termination is important because development of SE is associated with poorer prognosis. Patients presenting with seizure are admitted to the hospital depending on their risk of seizure recurrence, and the morbidity and mortality associated with recurrence. Patients should be discharged from the ED only if they have a normal (or baseline) neurologic exam.

Initiation of antiepileptic drug (AED) treatment in the ED does not affect long-term outcomes in patients presenting with their first seizure; therefore, the 2014 ACEP policy does not recommend that patients with first-time seizure receive an AED in the ED (Table 1).

In patients who present with seizure in the context of subtherapeutic AED levels, a loading dose should be administered. To determine the loading dose, the current corrected serum level should be subtracted from the goal serum level and multiplied by the dosing weight in kilograms. A loading dose of phenytoin can be administered either intravenously (IV) or orally; however, IV phenytoin can be loaded faster so that the patient can be discharged from the ED quicker [Swadron SP et al. Acad Emerg Med. 2004].

A patient presenting with SE who continues to experience seizures after receiving benzodiazepine, IV phenytoin, fosphenytoin, or valproate may be administered (level B recommendation), or IV levetiracetam, propofol, or barbiturates may be administered (level C recommendation) [Huff JS et al. Ann Emerg Med. 2014]. In such cases, systolic blood pressure and mean arterial pressure should be maintained at > 90 and > 70, respectively. In addition, the Neurocritical Care Society's (NCS) guidelines for the evaluation and management of SE recommend that these patients quickly receive continuous infusion of midazolam or propofol [Brophy GM et al. Neurocrit Care. 2012].

In all patients who are suspected to have nonconvulsive SE, as well as any patient who underwent hypothermia therapy after cardiac arrest, continuous EEG (cEEG) should be performed [Huff JS et al. Ann Emerg Med. 2014]. In one study, up to 33% of patients who received hypothermic therapy for cardiac arrest experienced seizures, which was associated with a greater rate of mortality [Knight WA et al. Epilepsy Res. 2013]. However, it is unknown whether seizure control decreases mortality in these patients. In patients with suspected nonconvulsive SE, the NCS guidelines recommend that cEEG should be initiated within 1 hour of event onset and continued for at least 48 hours [Brophy GM et al. Neurocrit Care. 2012].

In conclusion, Dr Bonomo highlighted that all patients presenting with a first-ever seizure should undergo CT, and potentially MRI, imaging, whereas patients with suspected nonconvulsive SE should be monitored by cEEG. In addition, he pointed out that an appropriate loading dose of phenytoin in patients with subtherapeutic levels is dependent on albumin. Treatment of refractory seizures should be quickly escalated, and propofol may be needed.

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