Diagnostic decision-making after a first and recurrent seizure in adults

Diagnostic Delay in Epilepsy: the Scope of the Problem

PURPOSE OF REVIEW

Diagnostic delay is an increasingly recognized issue in epilepsy. At the same time, there is a clear disparity between public awareness of epilepsy and that of other public health issues. A contributing factor for this seems to be a lack of studies testing interventions designed to improve seizure recognition. In this review, we summarize the main findings from recent studies investigating diagnostic delay in epilepsy, highlighting causes, consequences, and potential interventions in future research that may improve quality of care in this population.

RECENT FINDINGS

Building on prior evidence, diagnostic delay in patients with new-onset focal epilepsy has been identified as an important problem for patients with epilepsy. Such delay in diagnosis can lead to delayed treatment and potentially preventable morbidity and mortality including motor vehicle accidents. Nonmotor seizure semiology appears to be a major contributor for delay; such seizures are largely unrecognized when patients present to emergency departments for care. Improving recognition and diagnosis of recurrent nonmotor seizures in emergency departments represents a significant opportunity for improving time to diagnosis, particularly when patients present following a first lifetime motor seizure and meet diagnostic criteria for epilepsy. Diagnostic delay in epilepsy is a significant public health issue and recent studies have highlighted potential areas for intervention.

The Impact of Clinical Seizure Characteristics on Recognition and Treatment of New-onset Focal Epilepsy in Emergency Departments

OBJECTIVE

Many people with new-onset focal epilepsy initially seek evaluation in emergency departments (EDs), and treatment decisions in EDs can influence likelihood of seizure recurrence. Using data collected for the Human Epilepsy Project (HEP), we assessed the effect of clinical seizure characteristics on ED clinical management.

METHODS

There were 447 participants with new-onset focal epilepsy seen within 4 months of treatment initiation who were eligible and enrolled in HEP. Seizure calendars and medical records were collected. Based on clinical descriptions, seizures were categorized by semiology according to International League Against Epilepsy (ILAE) classifications as either focal nonmotor or focal motor seizures.

RESULTS

Overall, 279 of 447(62%) of participants had presented to an ED prior to or at time of epilepsy diagnosis. A total of 132 of 246 (53%) with initial nonmotor seizures presented to an ED. Of these, eight (6%) presented with a first-lifetime nonmotor seizure. The other 124 (94%) presented after multiple seizures: seven (5%) with multiple nonmotor seizures and 117 (89%) with a first-lifetime motor seizure after having prior nonmotor seizures. A total of 147 of 201 (73%) participants with initial motor seizures presented to an ED. Of these, 134 (92%) presented with a first-lifetime motor seizure and 13 (9%) with multiple motor seizures. There was no difference in the likelihood of antiseizure medication initiation between participants who had multiple prior nonmotor seizures followed by a motor seizure (thereby fulfilling the criterion for an epilepsy diagnosis) versus those presenting with a single lifetime motor seizure (39% vs. 43%). There was no difference in recognition of seizures as the presenting complaint (85% vs. 87%) or whether the participant was admitted or referred to a neurologist (87% vs. 79%).

CONCLUSIONS

This study contributes to evidence of underrecognition of nonmotor focal seizure semiologies in ED settings, which can support large-scale interventions aimed at improving recognition, specialist consultation, and treatment in ED settings.

Convulsant Effects of Abused Synthetic Cannabinoids JWH-018 and 5F-AB-PINACA Are Mediated by Agonist Actions at CB1 Receptors in Mice

Convulsant effects of abused synthetic cannabinoid (SCB) drugs have been reported in humans and laboratory animals, but the mechanism of these effects is not known. We compared convulsant effects of partial CB1R agonist ∆9-tetrahydrocannabinol (THC), full CB1R agonist SCBs JWH-018 and 5F-AB-PINACA, and classic chemical convulsant pentylenetetrazol (PTZ) using an observational rating scale in mice. THC did not elicit convulsions, but both SCBs did so as effectively as and more potently than PTZ. SCB-elicited convulsions were attenuated by the CB1R antagonist rimonabant or by THC, or by dose regimens of THC and JWH-018, which downregulate and desensitize CB1Rs. None of these treatments altered the convulsant effects of PTZ, although diazepam attenuated PTZ-elicited convulsions without altering SCB-induced convulsant effects. Repeated administration of a subthreshold dose of PTZ kindled convulsant effects, but this was not observed with the SCBs, and no cross-kindling was observed. Repeated administration of the SCBs resulted in tolerance to convulsant effects, but no cross-tolerance to PTZ was observed. Inhibition on Phase I metabolism via nonselective inhibition of CYP450s with 1-aminobenzotriazole potentiated the hypothermic effects of the SCBs and protected against the convulsant effects of JWH-018, but not those of 5F-AB-PINACA or PTZ. Incubation of human liver microsomes with the SCBs showed that JWH-018 is eliminated via oxidation, whereas 5F-AB-PINACA is not. These studies suggest that SCB-elicited convulsions are mediated by high intrinsic efficacy at CB1Rs and that benzodiazepines may not be effective treatments. Finally, drug metabolism may dramatically modulate the convulsant effects of some, but not all, SCBs.

Mobile EEG in epilepsy

The sensitivity of routine EEG recordings for interictal epileptiform discharges in epilepsy is limited. In some patients, inpatient video-EEG may be performed to increase the likelihood of finding abnormalities. Although many agree that home EEG recordings may provide a cost-effective alternative to these recordings, their use is still not introduced everywhere. We surveyed Dutch neurologists and patients and evaluated a novel mobile EEG device (Mobita, TMSi). Key specifications were compared with three other current mobile EEG devices. We shortly discuss algorithms to assist in the review process. Thirty percent (33 out of 109) of Dutch neurologists reported that home EEG recordings are used in their hospital. The majority of neurologists think that mobile EEG can have additional value in investigation of unclear paroxysms, but not in the initial diagnosis after a first seizure. Poor electrode contacts and signal quality, limited recording time and absence of software for reliable and effective assistance in the interpretation of EEGs have been important constraints for usage, but in recent devices discussed here, many of these problems have been solved. The majority of our patients were satisfied with the home EEG procedure and did not think that our EEG device was uncomfortable to wear, but they did feel uneasy wearing it in public.