Authors :
Presenting Author: Zachary Duarte, MD – University of Pittsburgh Medical Center, Erie
Tara Pirnia, PhD – University of Pittsburgh Medical Center
Shruti Iyer, MD – University of Pittsburgh Medical Center
Gabriela Pucci, MD – University of Pittsburgh Medical Center
Katie McFarlane, MS – University of Pittsburgh Neurology
Alex Israel, MD – University of Pittsburgh Medical Center
Carolina Cuello-Oderiz, MD – University of Pittsburgh Medical Center
Joseph Ta, MD – University of Pittsburgh Medical Center
Danielle Carns, PsyD – University of Pittsburgh Medical Center
Wesley Kerr, MD, PhD – University of Pittsburgh Department of Neurology
Rationale:
Functional seizures (FS) are paroxysmal neurological symptoms commonly associated with acute and chronic biopsychosocial stressors. The International League Against Epilepsy (ILAE) minimum certainty criteria for the diagnosis of FS emphasizes observation of the typical seizure(s) with video-EEG, video without EEG, or EEG without video (LaFrance et al. Epilepsia 2013). Recently, subspecialists in non-seizure functional neurological disorder (FND) have emphasized the importance of diagnosis based on positive signs because FND is not a diagnosis of exclusion. To evaluate those diagnostic principles in FS, we evaluated the rate of revision of an initial diagnosis of FS after observation of typical seizure(s) with and without positive signs.Methods:
Adult patients with an initial diagnosis of FS were identified at the University of Pittsburgh Medical Center. Indicators of an initial diagnosis of FS included referral to the multidisciplinary functional seizure clinic, discharge from the EMU after ictal observation of “nonepileptic events,” or an ICD-10 code for FS (F44.5). Based on subsequent clinical records, we evaluated the rate with which the diagnosis of FS was felt to be less likely. In particular, we evaluated if diagnostic revision occurred less in seizures observed with or without positive diagnostic signs for FS.Results:
549 patients (78% female, median age 34 years [interquartile range 24-46]) had an initial diagnosis of FS, of which 84% (460) continued to have an ILAE-defined “Clinically Established” or “Documented” certainty of FS throughout a median of 1.8 years of follow up. No patients with observed seizure(s) with positive diagnostic signs were later felt to be less likely to have FS. All 89 (16%) patients who, upon further evaluation, were felt to be less likely to have FS, had a diagnosis of FS based on observed scalp EEG negative seizure(s) without positive signs. A certain diagnosis of a non-functional seizure etiology was identified in 42 (47% of 89, 7.6% of 549), including epilepsy (22%, 20/89), dysautonomia (6%, 5/89), migraine (4%, 4/89), primary cardiac (3%, 3/89), other neurological conditions (4%, 4/89), primary psychiatric (2%, 2/89), sleep disorders (2%, 2/89), persistent postural-perceptual dizziness (1/89), and factitious disorder (1/89).Conclusions:
FS should not be considered a diagnosis of exclusion because the initial diagnosis of FS was revised with further information in 16% of patients, all of whose observed seizure(s) did not have positive signs. The most common conditions misdiagnosed as FS were epilepsy, dysautonomia, migraine, and primary cardiac conditions. Based on these results, we propose that the ILAE certainty criteria should be revised to emphasize observation of typical seizure(s) with positive diagnostic signs. That revision of the ILAE criteria could improve the certainty of the highest certainty category of “Documented” by excluding conditions misdiagnosed as FS, while also improving the care and reducing the perceived or real dismissal of patients with non-functional events without scalp EEG correlate. Funding:
NINDS NIH (K23NS135134), and Susan Spencer Scholarship from the AAN, AES, Epilepsy Foundation, and American Brain Foundation.