初老期に笑い発作を発症し前頭葉てんかんが疑われた1例

A Possible Case of Frontal Epilepsy with Gelastic Seizure and Onset at Presenile Age

はじめに

　てんかん性笑い発作は臨床的にまれな病態であり，視床下部過誤腫や皮質形成異常によるてんかんの症例に報告がみられるが，それらの発症年齢はほとんどが小児期である。今回我々は，初老期に笑い発作を発症し，発作時の脳波所見や臨床症状などから前頭葉てんかんが疑われた症例を経験したので，報告する。

　Gelastic seizure in the elderly is a rare form of epilepsy. We report the case of a 62-year-old man with frontal lobe epilepsy manifesting as a gelastic seizure.

　The patient had experienced weekly gelastic seizures with facial blushing and hand and feet moving while sleeping, since around the month of April. Similar seizures began to occur during the day since July of the same year, and the frequency of these seizures increased there after. The seizure was accompanied by loss of consciousness for approximately 5-15s. However, the postictal twilight state was not outstanding, and oral automatism was rarely seen after the seizure.

　Although neither plain nor contrast brain MRI revealed any abnormality, interictal EEG revealed spike discharges in the left frontal and left anterior temporal area, moreover ictal EEG showed predominant δ and θ rhythms in the left hemisphere. The patient was diagnosed with gelastic seizure because of frontal lobe epilepsy.

　The seizure was perfectly controlled with the administration of carbamazepine (200mg/day). Gelastic seizure is a rare symptom, but is seen in infants with conditions such as hypothalamic hamartoma and epilepsy due to cortical dysplasia. The onset age in this case was 62 years, which is extremely rare.