Table 3. Details of patients for which the early suspected etiology using the SEEIT was incorrect.

Pt	Age	Gender	Previous seizures	Etiology generated using the SEEIT	Final etiology	Case description	Explanation
1	54	F	No	Cryptogenic	Brain glioma	Small temporal glioma was missed in the  CT performed in ED, but seen on MRI  later. Of note, because seizures were  focal, the tool advised an MRI	Etiology missed on CT
2	76	M	No	Cryptogenic/  encephalitis?	Brain glioma	Because of new-onset refractory epilepsy  with normal CT and normal CSF analysis,  SEEIT evoked a cryptogenic SE or  encephalitis in early phase/autoimmune  process. The later MRI revealed a glioma	Etiology missed on CT
3	40	F	Yes	Drug related  (ciprofloxacin)	Known epilepsy  without  provocative  factors	Patient with known epilepsy experienced  SE in the context of ciprofloxacin  prescribed for UTI without systemic  involvement. The discharge summary  did not retain ciprofloxacin as  provocative factor	Disagreement on  causality judgment of  minor precipitants
4	57	F	No	Meningoencephalitis  (infectious)	Carcinomatous  leptomeningitis	SE after lumbar surgery for vertebral  metastasis (breast cancer). CSF  showed a pleocytosis (115 whitecells/  mm3). Infectious meningitis was  proposed by the SEEIT. Further CSF  analysis revealed metastatic cells	CSF data  misinterpreted
5	21	F	No	Meningoencephalitis  (infectious)	NMDA  encephalitis	Presented with refractory SE and  mild CSF pleocytosis. Possible CNS  infectious was retained using the  SEEIT. Further analysis didnot  find any infectious agent and revealed  NMDA antibodies	Failure to identify  a complex disease in  the emergency  setting
6	72	M	No	Remote ischemic  stroke	Lymphomatous  meningitis	Known for Waldenstrom disease. Initial  imaging showed an old previously  asymptomatic stroke retained as  responsible using the SEEIT. LP done  because of unexpected evolution revealed  lymphomatous meningitis	Remote brain  pathology  incorrectly retained
7	19	F	Yes	Known epilepsy  without  provocative  factors	Cryptogenic	History revealed a couple febrile seizures  during childhood and no other  explanation. Because of the long time  before recurrence of seizure, she was not  considered as having epilepsy before the  SE episode and thus considered as  cryptogenic	Disagreement on  causality judgment  of minor  precipitants
8	71	F	No	Drug related  (clozapine)	Posterior  reversible  encephalopathy  syndrome  (PRES)	In the context of severe anxiety for 3 days,  clozapine was prescribed and increased.  Then the patient presented with altered  mental status and visual hallucinations.  Focal SE was diagnosed after EEG. Initial  imaging was nonconclusive. The etiology  retained using the SEEIT was related to  the clozapine. Later MRI revealed a PRES	Etiology missed on CT
9	67	F	No	Meningoencephalitis  (infectious)	Cryptogenic	Refractory SE and fever at the presentation.  Despite a mild pleocytosis, the CSF remained  sterile. The pleocytosis was attributed to  seizures	CSF data  misinterpreted
10	75	M	No	Cryptogenic	HSV-1  encephalitis	Because of fever and new onset SE, the  SEEIT suggested a CSF analysis, which was  normal (four white cells). Later, PCR came  back positive for HSV-1. LP was  performed early (ca. 36 h after onset), so  the SEEIT warned against “false” normal  CSF in early phase of an encephalitis	CSF data  misinterpreted
11	46	F	Yes	Sepsis	Possible posterior  reversible  encephalopathy  syndrome  (PRES)	SE in the context of sepsis (pulmonary  origin) and known epilepsy. So, using the  SEEIT, sepsis was considered as a  provocative factor. Later MRI was  consistent with a PRES. However, it was  not excluded for certain that the MRI  changes were due to seizures	Etiology missed on CT
12	40	F	Yes	Sepsis	Known epilepsy  without  provocative  factors	SE in the context of fever, systemic  inflammatory response syndrome (SIRS)  and known epilepsy. So, using the SEEIT,  sepsis was considered as a provocative  factor. The complete evaluation did not  find any infectious source. The SIRS was  attributed to the SE itself	SIRS incorrectly  suspected
13	54	F	No	Acute ischemic  stroke	Brain abscess due  to Bacillus cereus  endocarditis	Patient known for acute myeloid leukemia.  Initial CT showed a probable new  ischemic stroke. Subsequent MRI revealed  an abscess. Endocarditis was subsequently  found	Etiology missed on CT
14	60	M	No	Cryptogenic	Alcohol  withdrawal	Alcohol withdrawal was denied during  initial assessment	Incomplete history  information
15	79	M	No	Dementia	Chronic  lymphocytic  leukemia with  CNS infiltration	Known for advanced dementia and chronic  lymphocytic leukemia. Initial imaging was  nonconclusive. MRI was performed 4 days  later and showed focal lesions likely due  to infiltrative lymphoma	Remote brain  pathology incorrectly  retained
16	69	F	No	Toxic-metabolic  (in the context of  a known CNS B  lymphoma)	Microangiopathic  hemolytic  anemia	Initial laboratory testing showed renal and  liver impairments of unknown origin. The  extensive evaluation revealed a  microangiopathic hemolytic anemia	Failure to identify a  complex disease in  the emergency  setting
17	71	M	No	Meningoencephalitis  (infectious)	Diffuse large  B-cell  lymphoma with  CNS  infiltration	Presented with SE preceded by  rapid cognitive decline. CSF showed  pleocytosis (728 white cells/mm3). CNS  infection was suspected. Extensive  evaluation did not find any etiology.  A malignant edema leaded to  herniation. Autopsy showed  a diffuse CNS infiltration by  large B-cell lymphoma	CSF data  misinterpreted
18	36	M	No	Brain lesion of  unclear origin	Cerebral  toxoplasmosis	Known for HIV. The evaluation in the  emergency department identified a newly  diagnosed mass without clear precision.  The complete evaluation revealed a  cerebral toxoplasmosis	Failure to identify a  complex disease in  the emergency  setting
19	76	M	No	Cryptogenic	Remote  subarachnoid  hemorrhage	The previous history of subarachnoid  hemorrhage was unknown at initial  presentation	Incomplete history  information
20	68	F	No	Toxic-metabolic	Acute ischemic  stroke	Presented with several mild metabolic  disturbances and the initial CT was  considered as normal. Subsequent MRI  advised by the SEEIT because of focality in  the clinical manifestation, revealed an  acute stroke	Etiology missed on CT
21	83	F	No	Cryptogenic	Acute ischemic  stroke	Initial imaging was considered as normal.  Subsequent MRI advised by the SEEIT  because of focality in the clinical  manifestation, revealed an acute ischemic stroke	Etiology missed on CT
22	79	F	No	Drugs intoxication	Dementia	Patient had mild increase in antipsychotic  treatment in setting of dementia and very  mild hypernatremia. However, the  features identified by the SEEIT were not  considered as sufficient to provoke SE	Disagreement on  causality judgment of  minor precipitants
23	49	F	Yes	Known epilepsy  without  provocative  factors	ASD related	Patient known for epilepsy treated with  LEV, VPA, and LCM. There was no  evidence of nonadherence in initial  evaluation. Later, low level of VPA level  became available and pointed out  nonadherence	Incomplete history  information
24	27	F	No	CNS infection	Cryptogenic  (NORSE)	Presented with flu-like symptoms a week  before entering a prolonged refractory  nonconvulsive SE in coma. The CSF in  early phase showed a mild lymphocytosis  (15 white bloodcells/mm3). Despite a very  broad evaluation including wide infectious  and autoimmune panels, no etiology was  found. She left the hospital 74 days later  with significant cognitive problems	CSF data  misinterpreted

CNS, central nervous system; CSF, cerebrospinal fluid; CT, computed tomography; ED, emergency department; F, female; HIV, human immunodeficiency virus; HSV, herpes simplex virus; LCM, lacosamide; LEV, levetiracetam; LP, lumbar puncture; M, male; MRI, magnetic resonance imaging; NMDA, N-methyl-d-aspartate; NORSE, new onset refractory status epilepticus; PCR, polymerase chain reaction; SE, status epilepticus; SEEIT, Status Epilepticus Etiology Identification Tool; UTI, urinary tract infection; VPA, valproic acid; WC, white cells.