Status epilepticus migrainosus: Clinical, electrophysiologic, and imaging characteristics

Spreading depression as an innate antiseizure mechanism

Spreading depression (SD) is an intense and prolonged depolarization in the central nervous systems from insect to man. It is implicated in neurological disorders such as migraine and brain injury. Here, using an in vivo mouse model of focal neocortical seizures, we show that SD may be a fundamental defense against seizures. Seizures induced by topical 4-aminopyridine, penicillin or bicuculline, or systemic kainic acid, culminated in SDs at a variable rate. Greater seizure power and area of recruitment predicted SD. Once triggered, SD immediately suppressed the seizure. Optogenetic or KCl-induced SDs had similar antiseizure effect sustained for more than 30 min. Conversely, pharmacologically inhibiting SD occurrence during a focal seizure facilitated seizure generalization. Altogether, our data indicate that seizures trigger SD, which then terminates the seizure and prevents its generalization.

Ictal Epileptic Headache: When Terminology Is Not a Moot Question

The relationship between headache and epilepsy is complex and despite the nature of this association is not yet clear. In the last few years, it has been progressively introduced the concept of the “ictal epileptic headache” that was included in the recently revised International Classification of Headaches Disorders 3rd edition (ICHD-3-revised). The diagnostic criteria for ictal epileptic headache (IEH) suggested in 2012 were quite restrictive thus leading to the underestimation of this phenomenon. However, these criteria have not yet been included into the ICHD-3 revision published in 2018, thus creating confusion among both, physicians and experts in this field. Here, we highlight the importance to strictly apply the original IEH criteria explaining the reasons through the analysis of the clinical, historical, epidemiological and pathophysiological characteristics of the IEH itself. In addition, we discuss the issues related to the neurophysiopathological link between headache and epilepsy as well as to the classification of these epileptic events as “autonomic seizure.”

Diagnostic criteria currently proposed for "ictal epileptic headache": Perspectives on strengths, weaknesses and pitfalls

PURPOSE

When we published the diagnostic criteria for "ictal epileptic headache" in 2012, we deliberately and consciously chose to adopt restrictive criteria that probably underestimate the phenomenon, rather than spread panic among patients and physicians who are reluctant to accept this entity.

METHODS

Here we discuss four intriguing clinical cases to highlight why we believe, to this day, that it is necessary to follow these restrictive diagnostic criteria.

CONCLUSIONS

EEG is not recommended as a routine examination for children diagnosed with headache, but it is mandatory and must be carried out promptly in cases of prolonged headache that does not respond to antimigraine drugs, if epilepsy is suspected or has been diagnosed previously. This is not a marginal or irrelevant question because possible isolated, non-motor, ictal manifestations should be taken into account before declaring that an epileptic patient is "seizure free" so as to ensure that any decision taken to suspend anticonvulsant therapy is safe.

Migraine and epilepsy: review of the literature

Migraine and epilepsy are disorders that are common, paroxysmal, and chronic. In many ways they are clearly different diseases, yet there are some pathophysiological overlaps, and overlaps in clinical symptomatology, particularly with regard to visual and other sensory disturbances, pain, and alterations of consciousness. Epidemiological studies have revealed that the two diseases are comorbid in a number of individuals. Both are now recognized as originating from electrical disturbances in the brain, although their wider manifestations involve the recruitment of multiple pathogenic mechanisms. An initial excess of neuronal activity in migraine leads to cortical spreading depression and aura, with the subsequent recruitment of the trigeminal nucleus leading to central sensitization and pain. In epilepsy, neuronal overactivity leads to the recruitment of larger populations of neurons firing in a rhythmic manner that constitutes an epileptic seizure. Migraine aura and headaches may act as a trigger for epileptic seizures. Epilepsy is not infrequently accompanied by preictal, ictal, and postictal headaches that often have migrainous features. Genetic links are also apparent between the two disorders, and are particularly evident in the familial hemiplegic migraine syndromes where different mutations can produce either migraine, epilepsy, or both. Also, various medications are found to be effective for both migraine and epilepsy, again pointing to a commonality and overlap between the two disorders.

"Headache and epilepsy"--how are they connected?

The relationship between headache and seizures is a complicated one, since these two conditions are related in numerous ways. Although the nature of this association is unclear, several plausible explanations exist: the two disorders coexist by chance; headache is part (or even the sole ictal phenomenon) of seizures or the post-ictal state; both disorders share a common underlying etiology; and epilepsy mimics the symptoms of migraine (as in benign childhood epilepsy). Seizures and headaches as well as their respective primary syndromes (epilepsy and headache/migraine) share several pathophysiological mechanisms. These mechanisms especially involve neurotransmitter and ion channel dysfunctions. Also, photosensitivity seems to play a role in the connection. In order to improve the care for patients with a clinical connection between migraine and epilepsy, it is necessary to try to understand more accurately the exact pathophysiological point of connection between these two conditions. Both experimental and clinical measures are required to better understand this relationship. The development of animal models, molecular studies defining more precise genotype/phenotype correlations, and multicenter clinical studies with revision of clinical criteria for headache/epilepsy-related disorders represent the start for planning future translational research. In this paper, we review the relationship between migraine and epilepsy in terms of epidemiology and pathophysiology with regard to translational research and clinical correlations and classification.

Should "migralepsy" be considered an obsolete concept? A multicenter retrospective clinical/EEG study and review of the literature

The few reports that have been published on the current International Classification of Headache Disorders, Second Edition (ICHD-II), criteria for migralepsy and hemicrania epileptica have highlighted the considerable confusion regarding this "hot topic" within both headache and epilepsy classifications (ICHD-II and International League Against Epilepsy [ILAE]). Indeed, the ICHD-II describes a migraine-triggered seizure as a rare event in which a seizure occurs during migraine aura; on the other hand, hemicrania epileptica is described as an "ictal headache" that occurs "synchronously" with a partial seizure. To confuse matters even further, neither the term migralepsy nor the term hemicrania epileptica is included in the currently used ILAE classification. On the basis of both a review of "migralepsy" cases in the literature and 16 additional retrospective multicenter cases, we suggest that the term migraine-triggered seizure or migralepsy be deleted from the ICHD-II classification until unequivocal evidence is provided of its existence, and that the term ictal epileptic headache be introduced into the ILAE classification.