Hemimegalencephaly accompanied by myoclonic status epilepticus.
We describe a boy (aged 2 years and 7 months) with hemimegalencephaly who developed myoclonic status, which improved dramatically after total callosotomy. The patient experienced seizures beginning at age 2 days, at which time electroencephalography revealed a right unilateral burst suppression pattern, and cranial magnetic resonance imaging revealed an enlarged right hemisphere. At age 8 months, habitual seizures increased to more than daily frequency. At the same time, myoclonic status epilepticus appeared with frequent erratic, partial, massive myoclonic seizures and clouding of consciousness. These signs were accompanied by diffuse spike and spike-wave patterns on electroencephalography, indicating myoclonic status in nonprogressive encephalopathy. Total callosotomy performed at age 10 months resulted in the complete disappearance of myoclonic status and prominent decrease in habitual seizures. This description of hemimegalencephaly is the first, to our knowledge, in which total callosotomy alleviated myoclonic status epilepticus. Although the mechanism of myoclonic status epilepticus remains unknown, our results suggest that cortico-cortical pathways are involved in this type of myoclonic status.
Department of Pediatrics, St. Luke's International Hospital, Tokyo, Japan.
Kentarou
K
Nakashima
Masaaki
M
Ogihara
Emi
E
Kasai-Yoshida
Shio
S
Tsuruta
Machiko
M
Nakagawa
Isao
I
Kusakawa
D002675:Child, Preschool; D004569:Electroencephalography; D004831:Epilepsies, Myoclonic / Q000150:complications* / Q000175:diagnosis; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D054220:Malformations of Cortical Development / Q000150:complications* / Q000175:diagnosis; D009460:Neurologic Examination