Painful seizures associated with a lesion in the midcingulate cortex

Abstract

Sirs, Pain as a symptom of an epileptic seizure is a rare condition, and the frequency of painful sensations during epileptic seizures is reported to vary between 0.3 and 2.8% [7]. Painful somatosensory auras have been described primarily in seizures with onset either contralaterally from the parietal lobe or from either temporal lobe, suggesting an involvement of the primary (SI) and secondary (SII) somatosensory cortices [4]. Neuroimaging studies have provided new insights into the physiology of pain [2] beyond the postcentral SI area and parietal SII area. The cingulate cortex seems to play multiple roles in pain perception, such as the integration of general effect, cognition, and response selection [5] and is involved in translating the painful sensation into an emotion of unpleasantness [8]. In contrast, the SI and SII areas discriminate the nature and localization of the pain stimulus. We report the case of a 17-year-old female with recurrent pain attacks of the right thigh. The patient had experienced four generalized tonic–clonic seizures (GTCS) at the age of 9 years. She was administered an anticonvulsant medication, first sulthiame and later carbamazepine, but she stopped taking both drugs due to side-effects shortly afterwards. No further GTCS ever occurred, but in the same year she began to suffer from acute attacks of very painful sensations within the right leg, mostly confined to the right thigh but sometimes stretching out to the knee and lower leg on the same side. The character of the pain sensation was difficult for the patient to describe—it was not burning and was felt to be localized deep within the thigh. There was no Jacksonian march nor was there any other accompanying sensation, such as tickling, tingling, or numbness. She denied the appearance of any motor symptoms, such as cramping or jerking, during the attacks. The attacks usually ceased promptly after a duration of less than 1 min and were accompanied by a slight feeling of dizziness, but without loss or alteration of consciousness. Before treatment, she experienced several seizures per month. We recorded two seizures during video-electroencephalogram (EEG) monitoring when the patient was 17 years; both demonstrated the typical semiology described above (see video at http://www.uniklinik-ulm.de/uploads/media/ painful_seizure.wmv). Ictal EEG showed a short theta seizure pattern bifrontally (left [ right) for 1.5 s with an embedded spike left fronto-centrally prior to the onset of muscle artefacts (see Fig. 1a). Interictal EEG showed a recurrent theta pattern bifrontally, similar to the one at the onset of the seizures. The cranial magnetic resonance imaging scan (1.5 T Siemens Magnetom Symphony using T1, T1 inversion recovery, T2 and FLAIR sequences) showed a lesion localized in the left middle cingulate cortex (MCC, centred around coordinates [-9, -16, 37] in Talairach coordinate space) (Fig. 1b, c), suggesting a focal cortical dysplasia (FCD). The patient has been treated with lamotrigine and has remained seizure free up to now. In previously reported cases, the onset of seizures causing painful sensations were either in the somatosensory areas SI or SII, in the temporal lobes or in other parts of the frontal lobes [7]. By contrast, our patient had a lesion in the contralateral MCC, suspected to be a FCD. The EEG findings were compatible with a seizure onset in that area. R. Roebling H. Lerche Neurological Clinic, University of Ulm, Ulm, Germany