Epileptic prodromes: Are they nonconvulsive status epilepticus?

PurposeThe aim of this study was to assess how frequently prodromes occur in an adult patient group from a tertiary referral epilepsy centre and to investigate the EEG changes during the prodromes.Methods578 consecutive patients were interviewed on subjective phenomena, experiences heralding the seizures, for at least 30 min before the start of the seizure. EEGs were recorded during the prodromes.ResultsTen out of 490 included patients had prodromes (2%). We were able to record EEG during prodromes in 6 patients. Three patients had EEG changes corresponding to nonconvulsive status epilepticus. Three patients had unrevealing EEG recordings during prodromes.ConclusionOur results suggest that at least in a part of the patients, the prodromes are actually ictal phenomena, and should be treated as nonconvulsive status epilepticus.     

Will MRI replace the EEG for the diagnosis of nonconvulsive status epilepticus,especially focal?

Magnetic resonance imaging (MRI) can now be used to diagnose or to provide confirmation of focal nonconvulsive status epilepticus (NCSE). Approximately half of patients with status epilepticus (SE) have signal changes. MRI can also aid in the differential diagnosis with generalized NCSE when there is a clinical or EEG doubt, e.g. with metabolic/toxic encephalopathies or Creutzfeldt-Jakob disease. With the development of stroke centers, MRI is available 24 h/24 in most hospitals. MRI has a higher spatial resolution than electroencephalography (EEG). MRI with hyperintense lesions on FLAIR and DWI provides information related to brain activity over a longer period of time than a standard EEG where only controversial patterns like lateralized periodic discharges (LPDs) may be recorded. MRI may help identify the ictal nature of LPDs. The interpretation of EEG tracings is not easy, with numerous pitfalls and artifacts. Continuous video-EEGs require a specialized neurophysiology unit. The learning curve for MRI is better than for EEG. It is now easy to transfer MRI to a platform with expertise. MRI is more accessible than single photon emission computed tomography (SPECT) or positron emission tomography (PET). For the future, it is more interesting to develop a strategy with MRI than SPECT or PET for the diagnosis of NCSE. With the development of artificial intelligence, MRI has the potential to transform the diagnosis of SE. Additional MRI criteria beyond the classical clinical/EEG criteria of NCSE (rhythmic versus periodic, spatiotemporal evolution of the pattern…) should now be systematically added. However, it is more complicated to move patients to MRI than to perform an EEG in the intensive care unit, and at this time, we do not know how long the signal changes persist after the end of the SE. Studies with MRI at fixed intervals and after SE cessation are necessary.     

Prolonged postictal stupor: nonconvulsive status epilepticus, medication effect, or postictal state?

We describe a patient who entered a stuporous state after receiving benzodiazepine treatment for generalized tonic-clonic status epilepticus. A diagnosis of generalized NCSE with tonic seizures was made on the basis of the clinical picture and response to barbiturate anaesthetic, although the EEG pattern was not typical of the changes previously described in tonic seizures-tonic status epilepticus. This report discusses the differential diagnosis of postictal stupor, nonconvulsive status epilepticus with tonic seizures and sedation caused by the emergency treatment of status epilepticus, and summarizes the literature on tonic seizures and tonic status epilepticus.     

Can anesthetic treatment worsen outcome in status epilepticus?

Status epilepticus refractory to first-line and second-line antiepileptic treatments challenges neurologists and intensivists as mortality increases with treatment refractoriness and seizure duration. International guidelines advocate anesthetic drugs, such as continuously administered high-dose midazolam, propofol, and barbiturates, for the induction of therapeutic coma in patients with treatment-refractory status epilepticus. The seizure-suppressing effect of anesthetic drugs is believed to be so strong that some experts recommend using them after benzodiazepines have failed. Although the rationale for the use of anesthetic drugs in patients with treatment-refractory status epilepticus seems clear, the recommendation of their use in treating status epilepticus is based on expert opinions rather than on strong evidence. Randomized trials in this context are lacking, and recent studies provide disturbing results, as the administration of anesthetics was associated with poor outcome independent of possible confounders. This calls for caution in the straightforward use of anesthetics in treating status epilepticus. However, there are still more questions than answers, and current evidence for the adverse effects of anesthetic drugs in patients with status epilepticus remains too limited to advocate a change of treatment algorithms.In this overview, the rationale and the conflicting clinical implications of anesthetic drugs in patients with treatment-refractory status epilepticus are discussed, and remaining questions are elaborated.This article is part of a Special Issue entitled “Status Epilepticus”.     

The yield of routine electroencephalography in the detection of incidental nonconvulsive status epilepticus – A prospective study

ObjectiveDiagnosis of NCSE is challenging, because the clinical presentation ranges from minimally altered mental status to coma without tonic–clonic activity. According to the largest retrospective study to date the incidence of NCSE is about 0.2%.MethodsWe prospectively investigated electroencephalography (EEG) recordings of 2514 consecutive patients that were referred to the Electrophysiology Unit of Department of Neurology, Vienna General Hospital between November 2009 and February 2011 (i.e. 16 months).ResultsThe incidence of NCSE in our study population was 0.8%, i.e. the EEG of 19 patients fulfilled the criteria of NCSE. In 53% of these patients the NCSE was not suspected by treating physicians. A severely reduced level of consciousness was found in 78% of patients with a suspected NCSE and in 30% of patients with an unsuspected NCSE, although the results were not statistically significant (p = 0.081). The delay between the admission to the hospital and diagnosis ranged between 0 and 51 days.ConclusionsNCSE was an unsuspected finding in more than half of the patients. Consciousness was severely impaired in only one third of these patients.SignificanceThese results highlight the importance of urgent EEG for the diagnosis of NCSE in patients even without significant impairment of consciousness.     

Nonconvulsive status epilepticus following cardiac arrest—are we missing the beginning?

Background

Status epilepticus (SE) is a common complication in patients surviving a cardiac arrest, but little is known about the frequency of nonconvulsive status epilepticus (NCSE).

Objectives

To compile the first the evidence from the literature of the overall frequency of NCSE in adults with persistent coma following cardiac arrest. Secondarily, to assess the emergence of NCSE in comatose resuscitated patients within the first hours of the return of spontaneous circulation (ROSC) and before inducing target temperature management.

Material and methods

The medical search engine PubMed was screened to identify prospective and retrospective studies in English reporting on the frequency of NCSE in comatose post-resuscitated patients. Study design, time of EEG performance, detection of SE and NCSE, outcomes, and targeted temperature management were assessed.

Results

Only three cohort studies (one prospective and two retrospective) reported on the EEG evaluation describing NCSE during ongoing sedation and target temperature management. Overall, we identified 213 patients with SE in 18–38% and NCSE in 5–12%. Our review found no study reporting NCSE in resuscitated adult patients remaining in coma within the first hours of ROSC and prior to targeted temperature management and sedation.

Conclusion

Studies of NCSE after ROSC in adults are rare and mostly nonsystematic. This and the low proportion of patients reported having NCSE following ROSC suggest that NCSE before target temperature management and sedation is often overlooked. The limited quality of the data does not allow firm conclusions to be drawn regarding the effects of NCSE on outcome calling for further investigations. Clinicians should suspect NCSE in patients with persistent coma before starting sedation and targeted temperature management.

     

Propofol in status epilepticus: little evidence,many dangers?

Abstract. Introduction: Several guidelines recommend the use of propofol for the treatment of refractory status epilepticus. An increased mortality rate in high dose, long-term treatment with propofol in adult patients was published recently. This prompted us to assess the literature on the scientific evidence for the efficacy and safety of propofol in the treatment of refractory status epilepticus. Methods: Medline was searched and the three authors independently reviewed all Medline abstracts for selection of papers. Results: We included 22 articles with original data on the use of propofol in refractory status epilepticus. Randomised clinical trials were lacking. Two non-randomised studies compared propofol with barbiturates and midazolam respectively. Both studies reported a higher risk of mortality for propofol. In addition, case reports and case series on the use of propofol as anaesthetic or sedative in children and adults reported several lethal cases. Conclusions: Serious doubts may be raised on the safety of propofol in the treatment of refractory status epilepticus. The two non-randomised studies and several case reports show an increased risk of mortality. Guidelines should not recommend the use of propofol as a routine treatment in refractory status epilepticus before a proper randomised trial has been performed.     

Therapeutically induced EEG burst-suppression pattern to treat refractory status epilepticus—what is the evidence?

Current guidelines advocate to treat refractory status epilepticus (RSE) with continuously administered anesthetics to induce an artificial coma if first- and second-line antiseizure drugs have failed to stop seizure activity. A common surrogate for monitoring the depth of the artificial coma is the appearance of a burst-suppression pattern (BS) in the EEG. This review summarizes the current knowledge on the origin and neurophysiology of the BS phenomenon as well as the evidence from the literature for the presumed benefit of BS as therapy in adult patients with RSE.

     

Sporadic Creutzfeldt–Jakob disease presenting as nonconvulsive status epilepticus case report and review of the literature

Creutzfeldt–Jakob disease (CJD) is the most common transmissible human spongiform encephalopathy. Seizures and status epilepticus (SE) are an uncommon finding in CJD. We report a 64-year-old woman with rapid cognitive decline who had electroencephalographic (EEG) changes suggestive of nonconvulsive status epilepticus (NCSE). She was later diagnosed with sporadic CJD (sCJD). We also reviewed the literature for published cases on this topic. MEDLINE was employed to identify all published reports of CJD and SE. We identified 8 references with a total of 12 cases with CJD and NCSE. sCJD should be considered in the differential diagnosis of any patient who presents with rapid cognitive decline and EEG changes consistent with status epilepticus.