Definitions of the strength of the recommendations (A, B, C, U) and classification of the evidence (Class I through Class IV) are provided at the end of the "Major Recommendations" field.
Electroencephalography (EEG)
Should an EEG be routinely ordered in an adult presenting with an apparent unprovoked first seizure?
Conclusion
For adults presenting with an apparent unprovoked first seizure, analysis of the evidence from 1 Class I and 10 Class II studies indicates that the EEG is probably helpful. It has a substantial yield with about 29% of EEGs demonstrating significant abnormalities, and these abnormalities predict the risk for seizure recurrence. In addition, EEG is regarded as a standard for the initial classification of seizures since it forms a basis for the "clinical and electroencephalographic classification of epileptic seizures."
Recommendations
- The EEG (routine) should be considered as part of the neurodiagnostic evaluation of the adult with an apparent unprovoked first seizure because it has a substantial yield (Level B).
- The EEG (routine) should be considered as part of the neurodiagnostic evaluation of the adult with an apparent unprovoked first seizure because it has value in determining the risk for seizure recurrence (Level B).
Neuroimaging Studies
Should a brain imaging study (computed tomography [CT] or magnetic resonance imaging [MR]) be routinely ordered in an adult presenting with an apparent unprovoked first seizure?
Conclusion
For adults presenting initially with an apparent unprovoked first seizure, the evidence from seven Class II studies indicates that a brain imaging study, either a CT or MRI, is probably useful. It has a significant yield of about 10%, which may lead to the diagnosis of disorders such as a brain tumor, stroke, cysticercosis, or other structural lesions, and may have some value in determining the risk for seizure recurrence.
Recommendation
Brain imaging using CT or MRI should be considered as part of the neurodiagnostic evaluation of adults presenting with an apparent unprovoked first seizure (Level B).
Laboratory Studies
Should blood counts, blood glucose, and electrolyte panels be routinely ordered in an adult with an apparent unprovoked first seizure?
Conclusion
Data from two Class II and four Class III studies showed that in adults presenting with an apparent unprovoked first seizure, although some abnormal laboratory results are reported, there is not sufficient evidence to support or refute recommending routine testing of blood glucose, blood counts, or electrolyte panels. The necessity for such studies should be guided by specific clinical circumstances based on the history, physical, and neurologic examination.
Recommendation
In the adult initially presenting with an apparent unprovoked first seizure, blood glucose, blood counts, and electrolyte panels (particularly sodium) may be helpful in specific clinical circumstances, but there are insufficient data to support or refute routine recommendation of any of these laboratory tests (Level U).
Should a lumbar puncture be routinely performed in an adult presenting with an apparent unprovoked first seizure?
Conclusion
Data from two Class III studies revealed significant abnormalities in up to 8% of a mixed group of patients presenting to an emergency department with a first seizure. However, the studies selectively performed lumbar punctures based on clinical findings and included patients who did not meet our inclusion criteria, such as those with acute symptomatic causes for their seizures or who had not returned to their normal baseline function.
Recommendation
In the adult initially presenting with an apparent unprovoked first seizure, lumbar puncture may be helpful in specific clinical circumstances, such as patients who are febrile, but there are insufficient data to support or refute recommending routine lumbar puncture (Level U).
Should toxicologic screening be routinely ordered in an adult presenting with an apparent unprovoked first seizure?
Conclusion
In two Class III studies considering the value of toxicology screening in adult patients presenting with a seizure, some patients with apparent unprovoked first seizure were included, but neither study investigated the use of routine toxicology screening for such patients.
Recommendation
In the adult presenting with an apparent unprovoked seizure, toxicology screening may be helpful in specific clinical circumstances, but there are insufficient data to support or refute a routine recommendation for toxicology screening (Level U).
Definitions:
AAN Classification of Evidence for Rating of Screening Articles
Class I: A statistical, population-based sample of patients studied at a uniform point in time (usually early) during the course of the condition. All patients undergo the intervention of interest. The outcome, if not objective, is determined in an evaluation that is masked to the patients' clinical presentations.
Class II: A statistical, non-referral-clinic-based sample of patients studied at a uniform point in time (usually early) during the course of the condition. Most patients undergo the intervention of interest. The outcome, if not objective, is determined in an evaluation that is masked to the patients' clinical presentations.
Class III: A sample of patients studied during the course of the condition. Some patients undergo the intervention of interest. The outcome, if not objective, is determined in an evaluation by someone other than the treating physician.
Class IV: Expert opinion, case reports, or any study not meeting criteria for Class I to III.
Classification of Recommendations
A = Established as effective, ineffective, or harmful (or established as useful/predictive or not useful/predictive) for the given condition in the specified population. (Level A rating requires at least two consistent Class I studies.*)
B = Probably effective, ineffective, or harmful (or probably useful/predictive or not useful/ predictive) for the given condition in the specified population. (Level B rating requires at least one Class I study or at least two consistent Class II studies.)
C = Possibly effective, ineffective, or harmful (or possibly useful/predictive or not useful/ predictive) for the given condition in the specified population. (Level C rating requires at least one Class II study or two consistent Class III studies.)
U = Data inadequate or conflicting; given current knowledge, treatment (test, predictor) is unproven. (Studies not meeting criteria for Class I–Class III).
*In exceptional cases, one convincing Class I study may suffice for an "A" recommendation if 1) all criteria are met, 2) the magnitude of effect is large (relative rate improved outcome >5 and the lower limit of the confidence interval is >2).
