BEWARE THE SRPIDs: STIMULUS-RESPONSIVE PSEUDO-ICTAL DISCHARGES ARE A COMMON AND IMPORTANT EEG PATTERN IN CRITICALLY ILL PATIENTS
Abstract number :
3.103
Submission category :
Year :
2002
Submission ID :
349
Source :
www.aesnet.org
Presentation date :
12/7/2002 12:00:00 AM
Published date :
Dec 1, 2002, 06:00 AM
Authors :
Lawrence J. Hirsch, Jan Claassen, Ronald G. Emerson. Dept. of Neurology, Comprehensive Epilepsy Center, Columbia University, New York, NY
RATIONALE: To describe an EEG pattern frequently encountered in ICU patients undergoing continuous EEG monitoring (cEEG).
METHODS: We reviewed clinical and EEG details of all patients with SRPIDs on cEEG between 7/1/2001 and 4/1/2002 (9 months). SRPIDs were defined as periodic, rhythmic or ictal-appearing discharges that were consistently induced or suppressed by alerting stimuli such as suctioning or sternal rub.
RESULTS: We identified 33 patients with SRPIDs (approximately 20% of all patients undergoing cEEG). Digital video was recorded in addition to EEG in 24 patients.
EEG features: specific patterns seen included periodic [dsquote]epileptiform[dsquote] discharges (N=21 patients: 9 lateralized (PLEDs), 11 generalized (GPEDs), 3 triphasic waves; some had more than one periodic pattern); rhythmic patterns with evolution with or without intermixed spikes fulfilling criteria for ictal discharges (N=18; 13 unilateral, 7 bilateral; some with both); or high voltage frontally-dominant rhythmic delta (FIRDA; N=14; 7 with at least one other SRPID pattern as well). All 33 patients had SRPIDs induced by stimulation; two also showed suppression of SRPIDs by stimulation at other times.
Clinical features: 8 patients had prior epilepsy, and 24 had an acute brain injury (including 8 SAH, 4 ICH, 3 trauma, 2 CNS infection, 2 infarct). Half (16/33) of the patients had definite seizures during the acute illness (in addition to SRPIDs), and half (17/33) did not. Ten patients had previous clinically obvious seizures. Eight patients had subclinical or very subtle seizures on video (unnoticed by staff/family); only 1 of these 8 had clinical seizures as well. Status epilepticus had been present in 11 patients: nonconvulsive in 3, convulsive in 4, and both in 4.
CONCLUSIONS: Periodic or ictal-appearing EEG patterns are commonly elicited by stimulation in critically ill ICU patients. Recording video, documenting patient stimulation on the EEG record, or repetitively examining patients during cEEG is necessary to recognize this pattern, avoid misinterpretation, and differentiate SRPIDs from spontaneous seizures. Further research is necessary to determine the pathophysiologic, prognostic and therapeutic significance of SRPIDs.