Periodic lateralized epileptiform discharges after complex partial status epilepticus associated with increased focal cerebral blood flow.

Department of Neurology, Medical College of Ohio, Toledo 43617, USA.
Journal of Clinical Neurophysiology (Impact Factor: 1.45). 12/2001; 18(6):565-9. DOI: 10.1097/00004691-200111000-00007
Source: PubMed

ABSTRACT Periodic lateralized epileptiform discharges (PLEDs) are typically associated with encephalitis, cerebral abscess, cerebral infarct, and status epilepticus. There is considerable debate as to whether this pattern is ictal or interictal when seen in association with status epilepticus. We present a patient with complex partial status epilepticus who developed PLEDs and remained comatose despite optimal drug therapy. Technetium 99m single-photon emission computed tomography (SPECT) showed hyperperfusion that resolved with further aggressive antiepileptic drug therapy, indicating that this pattern may indeed be ictal. Further studies are needed to define the significance of PLEDs in patients with status epilepticus. The role of SPECT in differentiating PLEDs as an interictal or ictal pattern also requires further study.

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    ABSTRACT: The goal of this report is to review periodic lateralized epileptiform discharges (PLEDs), particularly their associated symptoms, the possibility that the pattern represents a focal status epilepticus, and finally the usefulness of antiepileptic drugs (AEDs). The associated symptoms often include an "altered state of consciousness" or "confusional state," but also more specific symptoms have been noted, such as nystagmus retractorius, cortical blindness, depression, apraxia, amnesia, hemianopsia, hemiparesis, gaze preference or deviation, dysphasia, and speech impediment. PLEDs have often been referred to as an ictal pattern, and many investigators have viewed the condition an example of subclinical status epilepticus. The intense hypermetabolism and increased blood flow revealed by PET and SPECT scans have been considered to support the ictal nature of this waveform. Although the pattern is difficult to treat, the AEDs that have been reported as successful include carbamazepine, midazolam, pentobarbital, sodium valproate, and felbamate. As only subtle symptoms are, at times, present and therefore may be missed and the pattern is known to be difficult to treat, epileptologists who view the PLED pattern as only an EEG curiosity and decide against treatment may wish to reevaluate the electroclinical evidence related to this interesting and significant pattern.
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    ABSTRACT: Periodic lateralized epileptiform discharges are associated with a variety of acute neurological disorders such as stroke, encephalitis and intracerebral hemorrhage. This particular EEG pattern may also be seen in association with status epilepticus. There is a debate in the neurology literature whether this pattern represents ongoing seizure activity or is an interictal pattern. Researchers are now beginning to utilize functional imaging studies such as SPECT to help differentiate whether this EEG pattern is ictal or interictal. This chapter provides an overview of the current state of literature regarding this topic.
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