Early focal electroencephalogram and neuroimaging findings predict epilepsy development after aneurysmal subarachnoid hemorrhage

INTRODUCTION

Seizures are a common complication of subarachnoid hemorrhage (SAH) in both acute and late stages: 10-20 % acute symptomatic seizures, 12-25 % epilepsy rate at five years. Our aim was to identify early electroencephalogram (EEG) and computed tomography (CT) findings that could predict long-term epilepsy after SAH.

MATERIAL AND METHODS

This is a multicenter, retrospective, longitudinal study of adult patients with aneurysmal SAH admitted to two tertiary care hospitals between January 2011 to December 2022. Routine 30-minute EEG recording was performed in all subjects during admission period. Exclusion criteria were the presence of prior structural brain lesions and/or known epilepsy. We documented the presence of SAH-related cortical involvement in brain CT and focal electrographic abnormalities (epileptiform and non-epileptiform). Post-SAH epilepsy was defined as the occurrence of remote unprovoked seizures ≥ 7 days from the bleeding.

RESULTS

We included 278 patients with a median follow-up of 2.4 years. The mean age was 57 (+/-12) years, 188 (68 %) were female and 49 (17.6 %) developed epilepsy with a median latency of 174 days (IQR 49-479). Cortical brain lesions were present in 189 (68 %) and focal EEG abnormalities were detected in 158 patients (39 epileptiform discharges, 119 non-epileptiform abnormalities). The median delay to the first EEG recording was 6 days (IQR 2-12). Multiple Cox regression analysis showed higher risk of long-term epilepsy in those patients with CT cortical involvement (HR 2.6 [1.3-5.2], p 0.009), EEG focal non-epileptiform abnormalities (HR 3.7 [1.6-8.2], p 0.002) and epileptiform discharges (HR 6.7 [2.8-15.8], p < 0.001). Concomitant use of anesthetics and/or antiseizure medication during EEG recording had no influence over its predictive capacity. ROC-curve analysis of the model showed good predictive capability at 5 years (AUC 0.80, 95 %CI 0.74-0.87).

CONCLUSIONS

Focal electrographic abnormalities (both epileptiform and non-epileptiform abnormalities) and cortical involvement in neuroimaging predict the development of long-term epilepsy. In-patient EEG and CT findings could allow an early risk stratification and facilitate a personalized follow-up and management of SAH patients.

Implications of starting antiepileptic treatment prior to electroencephalography in first epileptic seizures

INTRODUCTION

This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure.

METHODS

We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72 hours after the seizure, and the factors related with seizure recurrence.

RESULTS

We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P = .25) or with the risk of recurrence within 6 months (P = .63).

CONCLUSIONS

Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

Implications of initiating antiseizure drugs prior to the performance of EEG in first epileptic seizures

INTRODUCTION

This study aimed to determine whether the administration of antiepileptic drugs (AED) alters the likelihood of detecting epileptiform abnormalities in electroencephalographies (EEG) performed early after a first epileptic seizure.

METHOD

We performed a retrospective, observational study including patients with a first seizure attended at our centre's emergency department between July 2014 and November 2019. We collected clinical data, as well as technical data on the acquisition and interpretation of the EEG performed within the first 72hours after the seizure, and the factors related with seizure recurrence.

RESULTS

We recruited 155 patients with a mean (SD) age of 48.6 (22.5) years; 61.3% were men. Regarding seizure type, 51% presented tonic-clonic seizures of unknown onset and 12% presented focal to bilateral tonic-clonic seizures. Thirty-nine patients (25.2%) received AED treatment before the EEG was performed: 33 received a non-benzodiazepine AED and 6 received a benzodiazepine. Epileptiform abnormalities were observed in 29.7% of patients. Previous administration of AEDs was not significantly associated with the probability of detecting interictal epileptiform abnormalities (P=.25) or with the risk of recurrence within 6 months (P=.63).

CONCLUSIONS

Administration of AEDs before an early EEG following a first seizure does not decrease the likelihood of detecting epileptiform abnormalities. These findings suggest that starting AED treatment immediately in patients with a high risk of early recurrence does not imply a reduction in the diagnostic accuracy of the test.

How soon should urgent EEG be performed following a first epileptic seizure?

PURPOSE

Patients with a first unprovoked epileptic seizure are often seen in emergency services. Electroencephalography (EEG) is indicated for diagnosing epilepsy, but the optimal time to perform this test has not been defined. This study aimed to determine the time interval following a seizure within which EEG has the greatest diagnostic yield.

METHODS

We conducted a retrospective study of all adult patients with a first unprovoked seizure who had undergone emergency EEG (July 2014-December 2019). Data collection included demographics, seizure type, time interval to EEG study, EEG pattern identified, and the prescription after emergency assessment. An optimal cut-off point for time to EEG was obtained, and an adjusted regression model was performed to establish associations with the presence of epileptiform abnormalities.

RESULTS

A total of 170 patients were included (mean age: 50.7 years, 40.6% women). Epileptiform discharges were identified in 34.1% of recordings, nonepileptiform abnormalities in 46.5%, and normal findings in 19.4%. A lower latency from seizure to EEG was associated with a higher probability of finding epileptiform discharges (median: 12.7 in the epileptiform EEGs vs. 20 h in the nonepileptiform EEGs, p < 0.001). The time interval associated with the highest probability of detecting an epileptiform EEG pattern was within the first 16 h after seizure onset: 52.1% of recordings performed before the 16-h cut-off showed these abnormal patterns compared with 20.2% performed after (p < 0.001). These findings were not related to the presence of an epileptogenic lesion in neuroimaging or to other clinical variables. The finding of epileptiform abnormalities was followed by a greater prescription of antiseizure drugs (96.4% vs. 66% in nonepileptiform patterns, p < 0.001).

CONCLUSION

The diagnostic yield of EEG following a first unprovoked epileptic seizure is highest when this test is performed within the first 16 h after onset of the event.

Prognosis of status epilepticus (SE): Relationship between SE duration and subsequent development of epilepsy

In animal models, SE duration is related to epileptogenesis. Data in humans are scarce, mainly in NCSE; therefore, we aimed to study the prognosis of SE de novo and which factors may influence subsequent development of epilepsy.

METHODS

We evaluated patients with SE without previous epilepsy at our hospital (February 2011-February 2014), including demographics, etiology, number of AEDs, duration of SE, mortality, and occurrence of seizures during follow-up.

RESULTS

Eighty-nine patients were evaluated. Median age was 69 (19-95) years old. Among them, 33.7% were convulsive. Regarding etiology, 59 were considered acute symptomatic (41 lesions, 18 toxic-metabolic), 17 remote or progressive symptomatic, and 13 cryptogenic. The median recovery time was 24h (30 min-360 h). In-hospital mortality was 29% (n = 26). After a median follow-up of 10 months, 58.7% of survivors (n = 37) showed seizures. Subsequently, we analyzed which factors might be related to the development of epilepsy, and we found that epilepsy development was more frequent with longer SE duration (37 vs. 23 h, p = 0.004); furthermore, patients with a toxic-metabolic etiology developed epilepsy less frequently (33% vs. 67%; p = 0.022). Epilepsy was also correlated (tendency) with focal SE (p = 0.073), a lesion in neuroimaging (p = 0.091), and the use of 2 or more AEDs (p = 0.098). Regarding SE duration, a cutoff of above 24h was clearly related to chronic seizures (p = 0.014); however, combining etiology and duration, the association of longer SE and epilepsy was significant in acute lesional SE (p = 0.034), but not in epilepsy with cryptogenic or remote/progressive etiology. After a logistic regression, only a duration longer than 24h (OR = 3.800 (1.277-11.312), p = 0.016) was found to be an independent predictor of the development of epilepsy.

CONCLUSION

In patients with SE, the longer duration is associated with an increased risk of subsequent epilepsy at follow-up, mainly in symptomatic SE due to an acute lesion. It is unclear if it might be the result of a more severe injury causing both prolonged seizures and subsequent epilepsy, and therefore whether more aggressive treatment in this group might avoid this possibility. Most of the patients with cryptogenic or remote/progressive SE developed epilepsy regardless of SE duration. This article is part of a Special Issue entitled "Status Epilepticus".

[Cortical spreading depolarization phenomena in patients with traumatic and ischemic brain injuries. Results of a pilot study]

OBJECTIVES

To determine the frequency and duration of cortical spreading depolarization (CSD) and CSD-like episodes in patients with traumatic brain injury (TBI) and malignant middle cerebral artery infarction (MMCAI) requiring craniotomy.

DESIGN

A descriptive observational study was carried out during 19 months.

SETTING

Neurocritical patients.

PATIENTS

Sixteen patients were included: 9 with MMCAI and 7 with moderate or severe TBI, requiring surgical treatment.

INTERVENTIONS

A 6-electrode subdural electrocorticographic (ECoG) strip was placed onto the perilesional cortex.

MAIN VARIABLES OF INTEREST

An analysis was made of the time profile and the number and duration of CSD and CSD-like episodes recorded from the ECoGs.

RESULTS

Of the 16 patients enrolled, 9 presented episodes of CSD or CSD-like phenomena, of highly variable frequency and duration.

CONCLUSIONS

Episodes of CSD and CSD-like phenomena are frequently detected in the ischemic penumbra and/or traumatic cortical regions of patients with MMCAI who require decompressive craniectomy or of patients with contusional TBI.

[Usefulness of the EEG recording in the diagnosis of cyclosporin A-induced encephalopathy]

INTRODUCTION

Cyclosporine A is one of the immunosuppressors most frequently used to prevent transplant rejection. Neurotoxicity is one of the complications often associated with it. These complications include acute encephalopathy, lethargy, confusion state, tremor, headache, motor disorders, visual changes and epileptic crises amongst others, even when blood levels are at what are considered to be 'therapeutic' levels.

CLINICAL CASES

We present the EEG anomalies found in 3 transplant patients (two liver transplants and on double lung transplant) to whom cyclosporin A had been given and who presented with status epilepticus. The EEG recordings showed paroxystic discharges of focal onset in the temporo-occipital areas. They were mainly correlated with the clinical findings of oculomotor and eyelid disorders.

CONCLUSION

The topography of the neurophysiological findings supports--as do the other clinico-radiological findings--localization preferably to the posterior areas of cerebral dysfunction associated with cyclosporin A. Although the physiopathological origin of the encephalopathy of patients treated with cyclosporin A seems to correspond to multiple factors, we wish to point out the diagnostic usefulness of the identification of EEG changes localized to the temporo-occipital areas in the recognition of the neurotoxic syndrome in these patients.