A first unprovoked convulsive seizure is a common neurologic presentation in the ED. The clinician faces the challenge of determining if the patient with a single seizure is predisposed to epilepsy, which is defined as 2 or more unprovoked seizures, and if an antiepileptic drug should be initiated to reduce the probability of recurrence. Approximately 40% to 50% of patients will experience recurrence after their first unprovoked seizure.2 A recent practice parameter issued by the American Academy of Neurology and American Epilepsy Society recommends that an EEG and a neuroimaging procedure (computed tomography [CT] or MRI of the head) be obtained in the diagnostic evaluation of an adult with a first unprovoked seizure.2 EEG is performed to assess for electrical abnormalities of the cortex of the brain such as spikes or sharp waves, which, if present, may be consistent with the diagnosis of epilepsy. In addition, abnormalities may suggest if the epilepsy syndrome is partial or generalized and thus guide the selection of an appropriate antiepileptic drug. MRI is superior to CT for identifying epileptogenic lesions.2 A higher risk of seizure recurrence after a first unprovoked seizure is associated with an abnormal neurologic examination, presence of a structural abnormality on neuroimaging, or abnormality on EEG. If 1 or more of these risk factors are present, the clinician may be more likely to recommend an antiepileptic drug. However, in the absence of risk factors, other factors may need to be taken into account. For example, a patient on anticoagulation might be at particularly high risk of significant injury if a seizure were to recur, and the clinician may lean towards treating this individual even if MRI and EEG were normal. There are insufficient data to support obtaining a neuron-specific enolase level (an enzyme released into the CSF when neural tissue is injured) in the routine evaluation of an adult presenting with an apparent first unprovoked seizure. A lumbar puncture is not necessary unless there is suspicion for an infectious or inflammatory process involving the central nervous system. This is unlikely in the case patient since consciousness was rapidly regained with resolution of the seizure.
- Obtain an EEG and a neuroimaging study.
2. Krumholz A, Wiebe S, Gronseth G, et al. Practice parameter: evaluating an apparent unprovoked first seizure in adults (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology and the American Epilepsy Society. Neurology 2007;69:
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