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Ictal asystole mimicking seizure deterioration in temporal lobe epilepsy Volume 17, numéro 3, September 2015

Vidéo

  • Ictal asystole mimicking seizure deterioration in temporal lobe epilepsy

Illustrations


  • Figure 1

Recurrence of seizure-related falls in chronic focal epileptic patients, in whom epileptic falls were previously controlled with anticonvulsive medication, is usually attributed to recurrence of generalized convulsive seizures. In this report, we present a patient with temporal lobe epilepsy (TLE) in whom video-EEG monitoring revealed an ictal asystole as the cause of myoclonic syncope during seizures arising from the left temporal lobe.

Case study

This 45-year-old woman had had epileptic seizures since the age of 13 years. Her seizures were heralded by non-specific auras which were followed by blank starring, inability to speak, and loss of responsiveness (dialeptic seizures) (Lüders et al., 1998). Rarely, generalized convulsions occurred. Her seizures were secondary to a cavernoma in the left mesial temporal gyrus, as documented by magnetic resonance imaging. Auras and dialeptic seizurescontinued despite lesionectomy of the cavernoma and anticonvulsant medication. One year after surgery, her family described recurrence of falls and cramps with loss of consciousness despite unchanged medication of 2,000 mg levetiracetam and 300 mg lamotrigine.

During continuous EEG monitoring, all interictal epileptiform discharges were recorded in the left temporal region. All of the six recorded habitual seizures arose from the left mesial temporal region. Asystoles were recorded during four of these seizures (figure 1). During asystole, her head dropped (while lying in bed) and she had several myoclonic jerks of the trunk and limbs. The asystole lasted from 22 to 35 seconds. The patient regained consciousness shortly after recurrence of normal cardiac rhythm.

The recording demonstrated that the head drop and jerks, and most likely the falls, are secondary to the ictal asystole, leading to syncope. After a pacemaker was implanted, she did not fall anymore during her seizures. Left anterior temporal lobe resection, two years after the implantation of the pacemaker, has now led to complete seizure control for more than two years.

Discussion

Recurrence of seizure-related falls may not necessarily be related to a recurrence of generalized convulsions, but may be secondary to ictal asystole, as demonstrated by our patient. Typically, anticonvulsant medication is more effective in controlling secondary generalized convulsions than focal seizures in patients with TLE (Mattson et al., 1992). The recurrence of falls in patients in whom only focal seizures without falls persist for a long period of time usually leads to the assumption that generalized convulsions reoccur. This typically leads to an adjustment of the anticonvulsant medication. However, video-EEG monitoring in our patient revealed ictal asystole and demonstrated that the atonic falls were most likely not the result of seizure generalization, but were due to ictal syncope. Myoclonic jerks during syncope are very common and may easily be misinterpreted as generalized convulsions (Lempert et al., 1994).

Video-EEG monitoring established the correct diagnosis and prompted the implantation of the pacemaker. The patient did not wish to have resective epilepsy surgery at that time. Two years later, she agreed to epilepsy surgery, which eventually led to seizure freedom. One might consider that earlier epilepsy surgery might have abolished the need for the pacemaker, but the patient was not willing to have epilepsy surgery at that time, and the pacemaker reduced her seizure and syncope-related risks. Implantation of cardiac pacemakers has been shown to prevent further falls and related lacerations in patients with ictal syncope (Moseley et al., 2011). Strzelczyk et al. (2011) reported two patients with drug-resistant epilepsy who refused pacemaker implantation as well as epilepsy surgery and continued to have recurrent seizures with falls and trauma.

The relation of ictal asystole to sudden unexpected death in epileptic patients (SUDEP) is yet unclear. No clear association could be shown in risk analyses of SUDEP and in the SUDEP patients observed during video-EEG monitoring (Nilsson et al., 1999; So et al., 2000).

We previously reported a similar female patient, in whom an event recorder demonstrated that her falls were associated with asystole. Implantation of a pacemaker abolished the falls but unmasked TLE, documented by video-EEG monitoring (Rémi and Noachtar, 2011). In this patient, anticonvulsant medication controlled her seizures.

In conclusion, when seizure-related falls reoccur in patients with focal epilepsies, one should consider ictal asystole leading to syncope during epileptic seizures. Video-EEG monitoring can resolve this issue.

Supplementary data

Summary didactic slides are available on the www.epilepticdisorders.com website.

Disclosures

None of the authors have any conflicts of interest to declare.