Abstracts

Rationale: Rapid identification of stroke mimics is a critical part of the evaluation of patients presenting with acute focal neurological deficits. Ictal/post-ictal deficits (IPIDs) regularly masquerade as acute stroke but their prevalence and characteristics are not well defined. Brain Volume perfusion CT (VPCT), an important tool in the acute stroke care pathway and early EEG monitoring may help in the early diagnostic of IPIDs. Thus, we aimed at describing the prevalence of IPIDs, their clinical characteristics and associated VPCT and emergent EEG findings in a retrospective cohort of patients with acute-onset focal neurological deficits.

Methods: Patients with IPIDs, defined as acute onset focal neurogical deficits associated to EEG slowing without brain imaging evidence for ischemic lesion, were retrospectively identified from our stroke unit registry of patients admitted for suspected stroke alert between January 2015 and September 2020 at the CUB-Hôpital Erasme, Brussels, Belgium. Only patients who had VPCT and spot EEG or continuous monitoring (cEEG) within 72 hours of symptoms onset were included. Semiology, clinical characteristics, VPCT and EEG results, as well as brain MRI when available were systematically reviewed.

Results: Out of 3727 patients who presented with suspected stroke, 111 were diagnosed with IPDs (3%) of which 35 met inclusion criteria. Past history of seizures was present in 5 out the 35 subjects. Their median National Institute of Health Stroke Scale (NIHSS) on admission was 9 (range 2-29) with, as main symptoms, confusion in 29/35, hemi-motor syndrome in 24/35 and hemi-neglect in 24/35 of the subjects. Mean and median duration of IPDs were 66 hours and 24 hours, respectively. VPCT disclosed an hyperperfusion pattern congruent with the symptoms in 7/35 of cases, an hypoperfusion pattern congruent with the symptoms in 20/35, incongruent patterns in 5/35 and was within normal limit in 3 out of 35 patients. Twenty-nine patients had an MRI with a diffusion sequence (DWI-MRI) of which none disclosed an acute ischemic lesion. Twenty-three patients underwent cEEG. Seizures were seen in 9 (39%) patients (8 focal and 1 generalized), of which 6 met criteria for non-convulsive status epilepticus (NCSE). Focal slowing was observed in 21 lateralized periodic discharges in 6 and sporadic inter-ictal discharges in 4. Twelve patients had spot EEG, which showed focal slowing in 11and sporadic inter-ictal discharges in 1.

Conclusions: IPIDs are rare stroke-mimics representing 3% of acute focal neurological deficits. Signs are often severe and last over 24 hours in half of the cases. Acute VPCT displays congruent lateralized hyperperfusion patterns in only 20% of cases but the yield of emergent EEG monitoring is higher, showing findings congruent with clinical manifestations in >90% cases, including 40% cases with ongoing subclinical seizures. Combination of VPCT and CEEG could help better identify and treat IPIDs.

Funding: Please list any funding that was received in support of this abstract.: No fundings.