18 November 2008
Speaker: Dr SINN Ting Ting, Maria (Associate Consultant (ICU), Tseung Kwan O Hospital, Hong Kong)
Chairman: Dr LEE Wai Chuen (Associate Consultant (A&IC), Tuen Mun Hospital)
A lady with limbic encephalitis with complex partial status epilepticus was presented.
Non-convulsive status epilepticus (NCSE) constitutes 25-50% of all cases of status epilepticus. Unlike generalized convulsive status epilepticus, currently there is no universal definition for NCSE yet. The difficulties are mainly related to the subtle clinical manifestations; it is hard to differentiate these manifestations from normal behavior or other non-epileptic medical disorders. Diagnosis cannot be relied simply on EEG criteria because particularly in comatose patients, the EEG can show a variety of rhythmic or periodic patterns and some of which are of unclear significance. A positive electroclinical response to anti-convulsant treatment may be helpful in the diagnostic process, but absence of response does not exclude the diagnosis. There is an ongoing debate regarding the duration of an episode before a diagnosis of NCSE can be made. Most epidemiological studies used a duration of 30 minutes though this is completely arbitrary.
Concerning the treatment of NCSE, one has to realize that it is a heterogeneous disease with multiple subtypes. NCSE can be broadly divided into focal and generalized types. Under focal NCSE, it can be further divided into simple partial, complex partial NCSE, and status epilepticus in coma. Under generalized NCSE, it can be divided into typical absence, atypical absence and late onset absence NCSE. In general, as most clinical forms of NCSE, with the exception of SE in coma, are not associated with acute systemic and chronic neurological complications, and aggressive pharmacological treatment seems to have a greater risk on morbidity and mortality than continuing non-convulsive seizure, a less aggressive pharmacological management is suggested. Therefore, when treating someone who continues to ‘convulse’ after benzodiazepines and phenytoin, instead of going directly to intubation and administering intravenous anaesthetics (midazolam, propofol or barbiturates) as in generalized convulsive SE, one may try other second-line anti-convulsants (valproic acid or phenobarbital), or even the newer anti-convulsants like topiramate and levetiracetam. Decison of whether proceeding to general anaesthesia if all of the above fail should be tailored for each patient.
The prognosis of NCSE is good, except for those SE in coma.
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