Abstract
Objective
The Salzburg criteria for nonconvulsive status epilepticus (NCSE) and the American Clinical Neurophysiology Society (ACNS) Standardized Critical Care EEG Terminology 2021 include a diagnostic trial with intravenous antiseizure medications (IV ASMs) to assess EEG and clinical response as a diagnostic criterion for definite NCSE and possible NCSE. However, how to perform this diagnostic test and assessing the EEG and clinical responses have not been operationally defined.
Methods
We performed a Delphi-process involving six experts to standardize the diagnostic administration of IV ASM and propose operational criteria for EEG and clinical response.
Results
Either benzodiazepine or non-benzodiazepine ASMs (non-BZD) can be used as first choice for a diagnostic IV ASM trial. However, non-benzodiazepines should be considered in patients who already have impaired alertness or are at risk of respiratory depression. Levetiracetam, valproate, lacosamide, brivaracetam, or (if the only feasible drug) fosphenytoin or phenobarbital were deemed appropriate for a diagnostic IV trial. The starting dose should be about two thirds to three quarters of the full loading dose recommended for treatment of status epilepticus, with an additional smaller dose if needed. ASMs should be administered during EEG recording under supervision. A monitoring time of at least 10 minutes is recommended. If there is no response, a second trial with another non-BDZ or benzodiazepines may be considered. A positive EEG response is defined as the resolution of the IIC pattern for at least three times the longest previously-observed spontaneous interval of resolution (if any), but minimum of one continuous minute. For a clinical response, physicians should use a standardized examination before and after IV ASM administration. We suggest a definite time-locked improvement in a focal deficit or at least one step improvement on a new dedicated one-domain 10-level NCSE response scale.
Significance
The proposed standardized approach of a diagnostic IV ASM trial further refines the ACNS and Salzburg diagnostic criteria for NCSE.
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