[A case of MELAS presenting complex partial status epilepticus].

We reported a 37-year-old man who presented complex partial status epilepticus as the initial symptom of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). He showed fluctuating consciousness disturbance, left homonymous hemianopsia, and paroxysmal conjugated eye deviation to the left. The lactic acid level was elevated in blood and CSF, and ragged-red fibers were observed in the biopsied muscle. MRI demonstrated T2-prolonged lesions in the right occipito-parieto-temporal lobes. Since a mutation of mitochondrial DNA (A3243G) was identified, he was diagnosed as having MELAS. On an ictal record, high amplitude, rhythmic sharp waves were observed at right parieto-temporo-occipital region. High amplitude slow waves were also observed on the right hemisphere, especially in the right frontal lobe. These ictal discharges gradually decreased at their amplitude and in frequency, and then ictal EEG turned to the interictal EEG. During an ictal period, conjugated eye deviation to the left side and consciousness loss were observed. These seizures were observed once every several minutes. During the interictal period, sharp waves and sharp-wave complexes were observed frequently at right parietal and posterior temporal lobes. The venous injection of diazepam (10 mg) normalized EEG quickly. When consciousness loss, especially fluctuating, was observed in the patients of MELAS, complex partial status epilepticus should be considered.