The Complex Relationship Between Epilepsy and Headache and the Concept of Ictal Epileptic Headache

Abstract

Key Points-Headache/migraine is often associated with epilepsy in children, as a pre-ictal, ictal, post-ictal or inter-ictal phenomenon.-Epidemiological aspects of the co-morbidity between epilepsy and headache are clearly different in children and adults.-Headache as a symptom, with migraine characteristics and/or tension-type headache characteristics, may be the only clinical ictal manifestation of an epileptic seizure: this condition is now classified as "ictal epileptic headache".-In particular, according to published criteria, the term "ictal epileptic headache" must be used in cases of a headache/migraine attack as the sole clinical ictal symptom of epileptic origin, confirmed by ictal-EEG recording and clinical-EEG responsiveness to intravenous antiepileptic drugs.-EEG is not recommended as a routine examination for children diagnosed with headache, but is mandatory and must be carried out promptly in cases of prolonged migraine/headache that does not respond to antimigraine drugs and in which epilepsy is suspected.-This is not a marginal question, because these possible, isolated, non-motor, ictal manifestations (i.e. ictal epileptic headache) should be taken into account before declaring an epileptic patient as "seizure free" so as to be able to suspend anticonvulsant therapy safely. SummaryThe possible link/comorbidity (causal or not causal) between epilepsy and headaches has been a topic of debate for over a hundred years, ever Since William Richard Gowers's time. In recent decades, new data have emerged in favor of a non-random relationship between these two entities. They are both characterized by transient attacks of altered brain function with a clinical, pathophysiological, genetic and therapeutic overlap, and may thus mimic each other. Indeed, the clinical distinction between headache and epilepsy may make the differential diagnosis a highly challenging task. Both are common and often co-morbid, with headache attacks in epilepsy being temporally related to the occurrence of epileptic seizures as a pre-ictal, ictal, post-ictal or inter-ictal event. Yet, they are both paroxysmal and chronic neurological disorders that share many clinical and epidemiological aspects, and they may both present with visual, cognitive, sensitive-sensorial and motor signs/symptoms; these neurophysiologicl phenomena arise from the cerebral cortex and are modulated by sub-cortical connections. Even from an epidemiological point of view, data in the literature regarding the co-morbidity between headache and epilepsy appear to be quite distinct in children. What makes this scenario even more variegated and complex are new data suggesting that a headache may, in some cases, even be the only ictal manifestation of an epileptic seizure. The latter condition, the so-called "ictal epileptic headache", is a new entity that has recently been cited in the new classification of headache disorders (ICHD-III), whose diagnostic criteria have very recently been defined and published. The data that have led, over the last decade, to the...

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

“…Data on perfusion MRI during IEH are not available in the here described cases, as well as in the all few single reported cases [5].…”

“…1) may be regarded as a possible "subtle" autonomic seizure. In this regard, it has previously been suggested that the IEH phenomenon be classified among "autonomic seizures", as happens for Panayiotopoulos syndrome [2,3,5,8,10]. It has also been suggested [2][3][4][5][11][12][13] that the age-specific lower activation threshold of the autonomic system ("the younger, the more autonomic") may explain the possible isolated headache manifestation during an epileptic seizure, as occurs in autonomic ictal manifestation for Panayiotopoulos syndrome in children [10].…”

“…Conversely, the headache/migraine reported to be the only manifestation of a nonconvulsive epileptic seizure in the patients described in the literature on IEH [3,5,13,17,22] was diagnosed exclusively on the basis of the EEG recording; the subsequent intravenous administration of anticonvulsant drugs in these patients was able to control the clinical-EEG picture (remission of both scalp EEG discharges and the headache). In addition, in two IEH cases described in the literature [14,21], the ictal EEG discharges were recorded purely by chance by means of deep M a n u s c r i p t 12 electrodes being used for neurosurgical purposes.…”

“…It has been suggested [2][3][4][5][11][12][13][16][17][18][19][20][21][22] that the activation threshold for cortical spreading depression (CSD) is inferior to that required for an epileptic seizure. This theory would explain why epileptic patients presenting a peri-ictal headache are seen considerably more often than migraine patients presenting an epileptic seizure.…”

“…It has been stressed that IEH criteria probably underestimate the true incidence and prevalence of this epileptic phenomenon and that the old concept of migralepsy (an event that is unlikely to exist) should be abandoned [2][3][4][5]. Indeed, "migralepsy" should be considered as a seizure from the very beginning, starting with the onset of an "ictal epileptic headache" immediately followed by other (sensorymotor or autonomic) ictal epileptic signs or symptoms [6][7][8]; according to this point of view, most "migralepsy" events may now be classified as "Hemicrania Epileptica" according to the International Classification of Headache Disorders (ICHD-3) criteria [9].…”