Interseizure EEG Slowing after ECT is not NCSE

Electroconvulsive therapy and seizure: a double-edged sword?

Electroconvulsive therapy (ECT) is a widely used therapeutic option of drug-refractory psychiatric disorders. ECT treats psychiatric symptoms by inducing brief controlled seizures through electrical stimulation, but ECT does not generally cause prolonged seizures or epilepsy. However, several studies have reported cases of prolonged seizures after ECT. This review aimed to determine the mechanism of epileptogenesis with neurobiological changes after ECT. Contrary to epileptogenesis by ECT, several cases have reported that ECT was successfully applied for treatment of refractory status epilepticus. In addition, ECT might be applied to hyperkinetic movement and psychiatric symptoms of encephalitis. We also investigated the anticonvulsant mechanism of ECT and how it controls encephalitis symptoms.

Tardive Seizures After Electroconvulsive Therapy

OBJECTIVES

Seizures that occur spontaneously after termination of an electroconvulsive therapy (ECT) seizure are termed tardive seizures. They are thought to be a rare complication of ECT, influenced by risk factors that affect seizure threshold. However, there has been limited review of tardive seizures with modified ECT. We aimed to review the literature to provide clinical guidance for the use of ECT after tardive seizures.

METHODS

PubMed, EMBASE, PsycInfo, and CINAHL databases were searched from inception to May 2021 to identify cases of modified ECT, with evidence of a seizure occurring within 7 days of a terminated ECT seizure. Data for demographic, medical, pharmacological, anesthetic, and ECT variables as well as management strategies were collected.

RESULTS

There have been 39 episodes of modified ECT-related tardive seizures published over a period of 40 years. In 97.4% of cases, there was at least 1 identified potential risk factor for seizures, including use of a seizure-lowering medication and/or preexisting neurological injury. Major complications were uncommon (<15% of cases); however, 1 fetal death and 1 subsequent suicide were reported. No case was diagnosed with epilepsy, although around 20% continued on antiepileptic medications. More than half of the included patients were retrialed on ECT, with only 15% developing further tardive seizures.

CONCLUSIONS

Seizures that occurred spontaneously after the termination of an ECT seizure are a rare complication of modified ECT. Recommencing ECT after a tardive seizure may occur after review of modifiable seizure risk factors and with consideration of antiepileptic medication and extended post-ECT monitoring.

Nonconvulsive Status Epilepticus After Electroconvulsive Therapy: A Review of Literature

BACKGROUND

The clinical presentation and risk factors of nonconvulsive status epilepticus (NCSE) in the context of electroconvulsive therapy (ECT) are poorly understood, and guidance regarding diagnosis and management remains scarce. In this article, we identify case reports of ECT-induced NCSE from literature, and discuss the presentation, diagnosis, and management of these cases in the context of what is known about NCSE from the neurology literature.

METHODS

A literature search on PubMed for case reports of NCSE after ECT.

RESULTS

We identified 13 cases for this review. Diagnosis in all cases was based on clinical features and electroencephalogram (EEG) findings. Clinical presentation was altered mental status or unresponsiveness, with subtle motor phenomena in some cases. All cases had nonspecific risk factors that have been associated with prolonged seizures and convulsions, such as recent discontinuation/reduction of benzodiazepines or anticonvulsants, and concurrent use of antipsychotics and antidepressants. All patients were treated with either benzodiazepines or antiepileptic agents. Outcomes in these post-ECT NCSE cases were generally favorable.

DISCUSSION

Although rare, post-ECT NCSE should be kept in mind by physicians when confusion or unresponsiveness develops and continues after ECT; multilead EEG is gold standard for diagnosis. An intravenous (IV) antiepileptic drug (AED) challenge can help clarify the diagnosis. Initial treatment is recommended with IV benzodiazepines, with a repeat dose if necessary. If seizures persist, IV AEDs are warranted. NCSE refractory to this treatment should be treated with a scheduled IV or oral AED. Serial multilead EEGs should be used to monitor resolution of symptoms.

CONCLUSION

NCSE after ECT is a rare but recognizable clinical event. A high clinical suspicion and low threshold for EEG is necessary for prompt diagnosis.