Discussion:
Although ictal pain is often associated with other seizure symptoms, it
can be the only manifestation of focal epilepsy and differentiating them
from others can be challenging. Among patients with ictal pain, those
who report it to their limbs are more likely to have an epileptic
cause1.
Under some pathophysiological conditions, operculo-insular lesions may
produce location-specific painful epileptic seizures. Functional imaging
studies have identified several cortical areas activated by painful
stimuli, referred as “pain matrix”, including, among others, the
primary somatosensory area, the supplementary motor area, the insula,
the anterior frontal or the posterior parietal
cortices4. Some cases of ictal pain with foci
originating in the frontal, parietal and temporal regions have been
described with surface EEG3,5. However, data from
functional cortical mapping by using direct cortical stimulation
suggests that the origin of painful somatosensory seizures arises solely
from the medial part of parietal operculum or the posterior and upper
part of the insular cortex6,7.
Taking into account the cortical mapping studies and the localization of
our patient’s glioblastoma, we suggest that the painful seizure has a
left operculo-insular origin and that the rhythmic activity captured on
the surface EEG represents propagation to the primary parietal cortex.
Paroxysmal contralateral pain can be the only manifestation of epileptic
seizures with operculo-insular cortex involvement. This knowledge is
useful to avoid misdiagnosis and to prompt appropriate management with
antiepileptic drugs.